INFRA SA Technical Response - SKA Telescope · The INFRA SA Technical Response responds to the SKA1 Baseline Design (as detailed in Applicable Document [AD 1] – SKA1 System Baseline

SKA.TEL.INFRA-SA.SE-TD-001

Commercial in confidence

Revision: 1

INFRA SA Technical Response

Document number................................................................................................ SKA.TEL.INFRA-SA.SE-TD-001

Revision .......................................................................................................................................................... 1

Classification .............................................................................................................. Commercial in Confidence

Author ................................................................................................................................................... SKA SA

Date ............................................................................................................................................... 2013/06/01

Client : SKA Organisation

Project : SKA Phase 1 (Pre-Construction Phase)

Type : Technical Response



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Document approval

Name Designation Affiliation Date Signature

Approved by C. van der Merwe

Senior System Engineer

SKA SA 6 June 2013

Approved by T. Cheetham General Manager: Infrastructure and Site Operations

SKA SA 7 June 2013



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Document history

Revision Date Of Issue ECP

/Number Comments

A 13 May 2013 NA Initial Issue

1 06 June 2013 NA Final issue for release

Document software

Package Version Filename

Word processor MS Word 2007 SKA TEL INFRA-SA SE-TD-001 Rev1.docx

Spreadsheet

Diagrams MS Visio 2007 Imbedded in word file

Company details

Name SKA SA Project Office

Physical/Postal

Address

17 Baker Street

Rosebank

Johannesburg

South Africa

Tel. +27 11 442 2434

Fax. +27 11 442 2454

Website www.ska.ac.za

http://www.ska.ac.za/



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Table of contents

Applicable and reference documents ....................................................................................... ix

Executive summary ............................................................................................................... 10

Scope appreciation ............................................................................................................... 15

SKA1 Baseline Requirements Identification.......................................................................... 15

Data Processing on site versus Cape Town ......................................................................... 17

6. Technical response ........................................................................................................... 19

6.1. SKA.TEL.INFRA-SA.SMON – Site Monitoring ................................................................. 19

6.2. SKA.TEL.INFRA-SA.POWER – Infrastructure Power ....................................................... 23

6.3. SKA.TEL.INFRA-SA.ACC – Infrastructure Access............................................................ 44

6.4. SKA.TEL.INFRA-SA.WAS – Infrastructure Water and Sanitation ..................................... 51

6.5. SKA.TEL.INFRA-SA.BLDS – Infrastructure Buildings ...................................................... 56

6.6. SKA.TEL.INFR-SA.FOUND – Infrastructure Antenna Foundations ................................... 73

6.7. SKA.TEL.INFRA-SA.COMMS – Infrastructure Communication Systems ............................ 76

6.8. SKA.TEL.INFRA-SA.VEH – VEHICLES ............................................................................ 87

6.9. SKA.TEL.INFRA-SA.SEC – Site Security ......................................................................... 88

Annexure A .......................................................................................................................... 93

Annexure B .......................................................................................................................... 94



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List of tables Table 1: Overview of SKA1 Baseline Requirements Identification and Options .......................... 15

Table 2: Summary of SKA1 Power Load Requirement.............................................................. 24

Table 3: Quality of Power and Redundancy Requirement ........................................................ 24

Table 4: Sub-elements of the MeerKAT Power System ............................................................ 25

Table 5: Capacity of current MeerKAT Power System .............................................................. 26

Table 6: MeerKAT Power System - Quality of Power and Redundancy ...................................... 27

Table 7: Power System Design Implication of the Load growing from MeerKAT to SKA1 ............ 27

Table 8: Summary of upgrades for Option 1 ........................................................................... 31

Table 9: Opportunities for optimisation of Power Load Requirements ....................................... 33

Table 10: South African industry standard design lifecycles ..................................................... 39

Table 11: Drawing Register for Farm Roads ........................................................................... 48

Table 12: Daily Water Demand .............................................................................................. 51

Table 13: Maintenance requirements ..................................................................................... 54

Table 14: Operations and maintenance good practice procedures ............................................ 55

Table 15: Electromagnetic shielding ....................................................................................... 62

Table 16: Business Network and Non-telescope CAM requirements .......................................... 80

Table 17: Frequency allocations of the current radio system .................................................... 84

Table 18: Antenna foundation solutions ................................................................................. 94

Table 19: Relevant layers and their geotechnical parameters ................................................... 95

Table 20: Summary of piled and pad foundations ................................................................... 98



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List of figures

Figure 1: ESKOM bulk power infrastructure in relationship to the SKA site ................................ 29

Figure 2: Proposed Layout of new Astronomy Substation for Option 1 ..................................... 32

Figure 3: Typical Schematic – Distribution Network ................................................................. 34

Figure 4: Connection of the antennas to the existing Eskom 22kV overhead power lines ........... 35

Figure 5: Klerefontein support base workshop plan ................................................................. 57

Figure 6: KAPB Basement Plan .............................................................................................. 64

Figure 7: Proposed container layout ....................................................................................... 66

Figure 8: Proposed location of Data Containers to the North West of the KAPB ......................... 67

Figure 9: Showing plan of cable tunnel and staircase housing.................................................. 68

Figure 10: Showing section through containers, steel canopy, staircase & cable tunnel ............. 69

Figure 11: Conceptual SKA SA LAN and associated network .................................................... 77

Figure 12: BMS interfaces with the ILS and the telescope CAM ................................................ 82

Figure 13: Radio network showing links between Base Stations and Repeater stations .............. 85

Figure 14: Locality map of the SKA Observatory ..................................................................... 88

Figure 15: Security details required at the Site Complex, Meys Dam and Losberg ..................... 89

Figure 16: Details of Deproclamation of Provincial Road .......................................................... 91

Figure 17: Small strain stiffness profiles used in the design ..................................................... 97



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List of images Image 1: KAT-7 Wind Sensors ............................................................................................... 19

Image 2: MeerKAT Pole Mast ................................................................................................ 19

Image 3: Wind Sensor .......................................................................................................... 19

Image 4: STI Sensor Unit as deployed to Site ......................................................................... 20

Image 5: STI Electronics that is fitted inside the CMC container .............................................. 20

Image 6: RFI Monitoring Trailer ............................................................................................. 21

Image 7: RFI Monitoring Equipment ...................................................................................... 21

Image 8: ESKOM bulk power infrastructure in relationship to the SKA site – Aerial view ............ 30

Image 9: Connection of the antennas in the Spiral arms to the existing Eskom 22kV overhead

power lines – Aerial view ............................................................................................. 36

Image 10: Typical Farm Road (existing MeerKAT road) ........................................................... 45

Image 11: Typical platform around the Antenna Foundation for MeerKAT ................................ 46

Image 12: Airstrip after priming ............................................................................................ 48

Image 13: Meys Dam sewer package treatment plant ............................................................. 55

Image 14: Losberg Construction Camp sewer package treatment plant .................................... 55

Image 15: Klerefontein Workshops, office and stores constructed for MeerKAT ........................ 56

Image 16: Klerefontein Workshops, office and stores .............................................................. 57

Image 17: The Losberg Site Complex with Dish Assembly Shed and Pedestal Integration Shed on

the left ....................................................................................................................... 58

Image 18: Karoo array processor building and power building ................................................. 63

Image 19: Meys Dam Construction Camp ............................................................................... 70

Image 20: Losberg Construction Camp .................................................................................. 71

Image 21: A typical hand held radio transceiver ..................................................................... 83

Image 22: A typical mobile radio transceiver .......................................................................... 83

Image 23: Radio Base Station at security office ...................................................................... 83

Image 24: Radio Repeater antennas at the SENTECH High Site (100km from core site) ............ 84



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List of abbreviations

ABBL As-Built Baseline

AR Acceptance Review

ATP Acceptance Test Procedure

ATR Acceptance Test Report

BMS Building Management Systems

CAM Control and Monitoring

CBL Contract Baseline

CCTV Closed Circuit Television

CDR Critical Design Review

COAR Consolidated OAR

CoDR Concept Design Review

DBL Design Baseline

FAT Factory Acceptance Test

ICD Interface Control Document

ILS Integrated Logistics Support

IOBL Initial Operational and Support Baseline

JPL Jet Propulsion Lab

KAPB Karoo Array Processor Building

KAR Karoo Astronomy Reserve

KAT Karoo Array Telescope

KAT-7 7-Dish KAT system

LAN Local Area Network

LSP Local Survivable Processors

MeerKAT 64 dish array

NRF National Research Foundation

OAR Observation Action Register

OBL Operational and Support Baseline

PBL Product Baseline

PC Personal Computer

PCA Physical Configuration Audit

PDR Preliminary Design Review

POP Point of Presence

QBL Qualification Baseline

QTP Qualification Test Procedure

QTR Qualification Test Report

RBL Requirements Baseline

RFI Radio Frequency Interference

RFI Radio Frequency Interference

RR Requirements Review

SA South Africa

SAAO South African Astronomical Observatory

SEMP System Engineering Management Plan

SKAO Square Kilometre Array Organisation

STI SXXX

UPS Uninterruptible Power Supply

UTP Unshielded Twisted Pair

VLAN Virtual Local Area Network

VoIP

VSAT

Voice over IP

Very Small Aperture Transceiver



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Applicable and reference documents

Applicable Documents

[AD 1] PE Dewdney, SKA1 System Baseline Design, SKA-TEL-SKO-DD-001-1_BaselineDesign1

Rev 1.

Reference Documents

[RD 1] T Cheetham and C van der Merwe, INFRA SA Cost Breakdown Structure (CBS),

SKA.TEL.INFRA-SA.MGT-MD-006 Rev 1;

[RD 2] T Cheetham and C van der Merwe, INFRA SA Risk Register, SKA.TEL.INFRA-SA.MGT-MP-

003 Rev 1;

[RD 3] C van der Merwe and C Taljaard, INFRA SA ILS Proposal, SKA.TEL.INFRA-SA.SE-ILS-001 Rev 1;

[RD 4] T Cheetham and C van der Merwe, INFRA SA High-Level Schedule, SKA.TEL.INFRA-SA.MGT-MD-004 Rev 1;

[RD 5] Z Stegmann, Eskom Report: SKA Project: Maximum Power Available at the SKA Core Site

feedback, 13 May 2013;

[RD 6] A Tiplady, T. Monama, INFRA SA Array Layout Report, SKA.TEL.INFRA-SA.SE.RPT.001

Rev 1.

[RD 7] T Cheetham and C van der Merwe, INFRA SA Work Breakdown Structure (WBS),

SKA.TEL.INFRA-SA.MGT-WBS-001 Rev 1.



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Executive summary

This document has been structured according to the INFRA SA Work Breakdown Structure (WBS), which can be found in Reference Document [RD 7] – INFRA SA Work Breakdown Structure (WBS).

The INFRA SA Technical Response responds to the SKA1 Baseline Design (as detailed in Applicable Document [AD 1] – SKA1 System Baseline Design).

SKA.TEL.INFRA-SA.SMON – Site Monitoring

No requirements were defined in [AD 1] – SKA1 Baseline Design in terms of the provision of additional site monitoring equipment on site for SKA1.

An assumption has been made that additional wind sensors, STI Monitoring equipment and RFI

equipment will be added to the existing equipment currently deployed on site in South Africa. Provision has been made for additional infrastructure required for this equipment which includes the

following:

Foundations;

Trenching, power cabling and optic fibre ducting;

Connection boxes, fibre splice domes and optic fibre cabling (to be provided by SaDT);

Pole masts;

Earthing and lightning protection.

SKA.TEL.INFRA-SA.POWER – Infrastructure Power

POWER.GRID – Upgrade to Grid Power

Based on modelling and optimisation and still considering the SKA1 baseline design requirements, two options are presented to address the grid power supply to site for SKA1, namely:

Option 1: Upgrade of the grid power network (Total of 8.7MVA) required as per SKA1

baseline;

Option 2: Optimising the existing bulk power supply to the site to cater for the required load

(Total of 4.9MVA) as per amended requirements.

In both options, the outer skirt Antenna’s (21 Antennas) will be supplied by existing Eskom rural over-head power lines.

POWER.RETC – Upgrade to Electrical Reticulation (MV and LV)

Losberg Site Complex

As per the SKA1 Baseline Design, it is estimated that the total power requirement at the Losberg Site

Complex is 4.3MVA. Calculations of the total number of processor racks required for both MeerKAT and SKA1 amount to 316 racks. In order to respond to the SKA1 Baseline Design, Option 1 is

considered:

Option 1: Utilisation of the existing Karoo Array Processor building at the Losberg Site

Complex and the provision of a new SKA1 Container Shed housing RFI-shielded containers to

accommodate the additional processor racks. An assumption has been made that the RFI-

shielded containers will be supplied by the pulsar timing group. In addition to the above, the

INFRA SA Consortium has deviated from the SKA1 Baseline Design by assuming that the data

processing will take place on site as opposed to Cape Town. The reasoning for this deviation

is explained in Section 6.5.4. Should the proposed container option not be considered

feasible by the SKAO, the alternative option will be to construct a new building at the



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proposed “Astronomy Complex” where the 132kV/33KV substation will be constructed

(should this be required). This option has not been costed in response to the RfP.

Option 2: The INFRA SA Consortium has done further modelling on the SKA1 Baseline

Design where the proposed updated SKA1 requirement was identified to be 106 processor

racks in total. Based on this modelling, the total number of processor racks for MeerKAT and

SKA1 can be accommodated in the existing Karoo Array Processor building.

For both options, the 21 Spiral Arm Antennas are supplied from existing Eskom rural overhead power

lines in the area.

Antenna Core Array Reticulation

As per the SKA1 Baseline Design, the baseline array configuration received from the SKAO was

optimised by considering the local topography and EMC characteristics. Reference can be made to [RD 6] - INFRA SA Array Layout Report in the “Reference Documents” file which forms part of this

submission.

No additional MV feeder cables will be required from the existing Power Building on site to the SKA1 antennas. The total power requirement for the SKA1 antennas is 2.8MVA.

The existing three-leg MV cable ring network provided for MeerKAT will accommodate the required SKA1 loading requirements.

The existing on-site reticulation network will be expanded to supply the new core and outer skirt

antennas with power where the MV cables will cut into the existing ring network. Most of the existing 315kVA miniature substations provided for MeerKAT can be re-used for SKA1 with some units having

to be upgraded to 500kVA.

21 Antennas on the spiral arms with be supplied by existing Eskom rural overhead power lines.

It should be noted that the optic fibre design will need to be aligned with the existing MeerKAT and proposed SKA1 electrical reticulation design.

Existing Construction Camps Power Supply

The existing power and back-up supply to the Meys Dam and Losberg construction camps will be re-used for SKA1.

POWER.KAPB – Upgrade to KAPB Power (including DRUPS)

Option 1: In terms of the SKA1 Baseline Design, the total on-site power requirement is 8.7MVA, which includes the existing KAT-7, MeerKAT and SKA1 power requirements.

In order to meet the total site requirement of 8.7MVA, the following changes will be required:

Install two new 5MVA 33/22kV oil-type transformers outside the existing Power building and

remove existing 2x2,5MVA 33/22kV transformers;

Reserve the DRUPS inside the KAPB for 400V KAPB and site complex loads and install new

DRUPS auxiliary transformer to supply its ancillaries;

Install four containerised Rotary UPSs to supply the 3,4MVA to the antennas (1,25MVA units

in a 3 + N configuration, supplying at 22kV);

Install two containers containing necessary medium voltage switchgear, complete with HVAC,

fire detection, etc;

Install an additional 1,25MVA Rotary UPS inside the Power Building, to supply the 3,8MVA to

the local Losberg site loads including data centre components (thus the 400V loads).



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The INFRA SA Consortium has undertaken further modelling and has presented the following alterative option:

Option 2: Re-use the existing Power Building based on the proposed amended power requirements derived from the KAT-7 and MeerKAT experience for SKA1 (5MVA) with the following addition:

Install an additional two 1,25MVA DRUPS inside the provided space inside the existing Power

Building.

Maintenance considerations, reliability and availability have been discussed in terms of both options

provided.

SKA.TEL.INFRA-SA.ACC – Infrastructure Access

The following will be provided for in response to the SKA1 Baseline Design:

Sealing of the Provincial road to site;

The provision of basic farm roads to the SKA1 core antennas;

Re-use of existing farm roads which will be upgraded where required for the SKA1 outer

antennas;

The existing all-weather landing strip will be utilised for SKA1.

The SKA1 road layout is based on Reference Document [RD 6] - INFRA SA Array Layout Report in the

“Reference Documents” file which forms part of this submission.

Maintenance and material requirements for the above are furthermore described in Section 0.

SKA.TEL.INFRA-SA.WAS – Infrastructure Water and Sanitation

It is estimated that the SKA1 peak water demand will be 634kl/day. Existing boreholes on the MeerKAT site are able to supply approximately 570kl/day. Additional geo-hydrological studies on

water availability will be executed as part of the site characterisation studies. Additional boreholes will have to be provided for SKA1.

Additional water treatment and waste management plants will be provided at both Construction Camps for SKA1 and at the Losberg Site Complex.

SKA.TEL.INFRA-SA.BLDS – Infrastructure Buildings

BLDS.SBASE – Klerefontein Support Base (all buildings)

As per the SKA1 Baseline Design, an assumption has been made that the existing buildings at the Klerefontein Support Base will be re-used for SKA1. As indicated in the technical response, the draft

CON OPS document (under development by SKAO) is still under development and the Logistic Support Analysis (LSA) needs to be undertaken during Stage 1 to confirm that the existing buildings,

resources, spares etc. are sufficient for SKA1.

BLDS.SPLEX – Site Complex

Dish Assembly Shed and Pedestal Integration Shed

As per the SKA1 Baseline Design, an assumption has been made that the existing Dish Assembly Shed and Pedestal Integration Shed will be re-used for SKA1. It should however be noted that there

is a maximum width clearance of 18.155m in the Dish Assembly Shed and the width will need to be

re-assessed for the SKA1 dish design. Similarly, there is a maximum height and width restriction on the Pedestal Integration Shed which must be reassessed during Stage 1 to confirm that the SKA1

dish/pedestal can fit into both sheds.



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Karoo Array Processor Building

Reference can be made to Section 6.2.3 which describes the two options considered for the KAPB.

Additional HVAC units will be installed in the KAPB and a new HVAC unit will supply the RFI-shielded containers for Option 1 (SKA1 Baseline). The use of the existing KAPB as presented in Option 2

(optimised option) will require additional HVAC units provided in the KAPB.

Power Building

Reference can be made to Section 6.2.3 which describes the expansion of equipment within the

existing Power Building for the SKA1 Baseline Design (Option 1) and the alternative option considered (Option 2).

SKA1 Container Shed

The INFRA SA Consortium has proposed the construction of a Container Shed for SKA1 to house a number of RFI-shielded containers which will accommodate additional racks required in terms of the

SKA1 Baseline Design. The actual number of containers will be determined during Stage 1 if this option is considered.

Construction Camps

As per the SKA1 Baseline Design, the Losberg and Meys Dam construction camps will be re-used for SKA1. The existing camps will be able to accommodate the anticipated number of contractors

required for SKA1.

BLDS.HQ – Cape Town Headquarters

As per the SKA1 Baseline Design, floor space will be leased in Cape Town for SKA1. The SKA SA is

currently in discussion with their property agent to expand the office floor space at The Park, Pinelands. It is anticipated that SKA1 can also be accommodated within The Park building (however

this must be communicated urgently to the SKA SA).

As a second option, the SKA SA is in discussions with the Western Cape Government to secure land

with the intention of constructing a new building for SKA SA from 2017 onwards. Should the SKAO

wish to pursue this option further for SKA2, the SKAO would be required to enter into a separate Memorandum of Agreement with the SKA SA/NRF and the Western Cape Government in the near

future.

SKA.TEL.INFRA-SA.FOUND – Infrastructure Antenna Foundations

The SKA1 configuration is based on Reference Document [RD 6] - INFRA SA Array Layout Report in

the “Reference Documents” file which forms part of this submission.

The Antenna Foundation loading requirements for a 15m diameter dish have been based on the

loading requirements indicated in the SSG Request for Information, 2011.

Based on the local geotechnical conditions, it is anticipated that there will be a combination of concrete piled foundations and concrete pad foundations. The design and fabrication of the anchor

cage assembly (interface between the Antenna Positioner and the Antenna Foundation will be the responsibility of the DISH Consortium). The design of the Antenna Foundations makes provision for

fibre ducting (to be provided by the SaDT Consortium), sleeves housing the LV electrical cable and earthing and lightning protection.

SKA.TEL.INFRA-SA.COMMS – Infrastructure Communication Systems

No requirements were defined in [AD 1] – SKA1 Baseline Design relating to Communication Systems. The INFRA SA Consortium has made assumptions on requirements based on what has been

implemented for MeerKAT and what needs to be expanded to accommodate SKA1.



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COMMS.LAN – Upgrade to LAN System

The SKA SA is deploying LAN infrastructure for MeerKAT which interfaces with the long-haul optic

fibre backbone from site to Cape Town. This infrastructure provides access to a variety of

information services on site, Cape Town and in Johannesburg which include:

Scientific data (unidirectional to Cape Town);

Control and Monitoring of telescopes;

Webcam data for telescopes;

BMS Access Control;

Voice (IP telephony);

BMS CCTV and BMS Data;

Video Conferencing;

Internet Access and general data, mail etc;

Network authorisation.

It is anticipated that the MeerKAT LAN infrastructure will be expanded for SKA1 to provide the

following:

Extension of the LAN to the SKA1 Container Shed housing RFI shielded containers;

Expansion of the IP telephony platform;

General expansion of the LAN capacity.

COMMS.BMS –Upgrade to Building Management System

The existing Building Management System deployed for MeerKAT monitors the key performance factors of the infrastructure, which include the grid power supply; Rotary UPS power; Data Centre

cooling systems; fire systems; access control; lights, water systems, emergency power systems and Antenna power distribution. The BMS is an Ethernet based system and interfaces with the Integrated

Logistic Support (ILS) management system and the Telescope Control and Monitoring sub-system.

It is envisaged that additional BMS monitoring points will be required for SKA1 equipment deployed on the site.

COMMS.RADIO – Upgrade to Emergency Communication Radio System

An emergency communication network has been deployed on site for KAT-7 and MeerKAT to provide

a means for communication on site for contractors, SKA SA Staff and Security staff. The network

operates on 4 repeater frequency pairs, 2 simplex frequencies and 6 CTCSS. It is anticipated that the existing radio network will be re-used for SKA1 with the following additions:

Allocation of additional channels (additional tone frequency tone panels);

Depending on the coverage of the spiral arms, additional repeater stations may be required.

SKA.TEL.INFRA-SA.VEH – Vehicles

The SKAO has established a CON OPS Working Group to define the Concept of Operations for SKA1.

Further work is required during Stage 1 on the Concept of Operations and the Logistic Support Analysis to determine the logistical support, spares, vehicles and stores requirements for SKA1. An

assumption has been made that the existing maintenance vehicles on site will be re-used for SKA1. Additional utility vehicles, people transporters, skyjack and trailers will need to be provided for SKA1.

SKA.TEL.INFRA-SA.SEC – Site Security

The SKA SA has a Service Level Agreement in place with a registered Security Service Provider who provides security/access control at Klerefontein; at the access controlled boom gates entering the site

and on site. It is anticipated that additional security guards will be deployed for SKA1 when the

Provincial road to site has been de-proclaimed. This will further limit access control to the site in future.



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Scope appreciation

In responding to the RfP, the INFRA SA Consortium has followed the principle of making full-use of the Precursor (MeerKAT) infrastructure with a natural build-out to SKA1, while considering possible

options for the various Infrastructure and Power sub-elements in an effort minimise capital costs for the design and delivery of SKA1. The options presented in the Technical Response below have taken

Applicable Document [AD 1] - SKA1 Baseline Design into consideration with the requirements on the

Infrastructure and Power sub-elements identified in Table 1. The INFRA SA Consortium has undertaken further modelling and analysis on the SKA1 baseline requirements and proposed

alternative options which should be considered further during Stage 1.

Interface meetings and Interface Control Documents will be convened with all Consortia to define and

confirm requirements for the respective sub-elements related to infrastructure and the telescope

following the response to the RfP and during Stage 1. As can be seen from the options presented in the Technical Response below, assumptions have been made on certain requirements in an effort to

provide options for consideration and associated costs at this early stage.

SKA1 Baseline Requirements Identification

As per Applicable Document [AD 1] – SKA1 Baseline Design, the INFRA SA Consortium has extracted

the following Infrastructure and Power Requirements applicable to South Africa. Reference can be made to Table 1.

Table 1: Overview of SKA1 Baseline Requirements Identification and Options

WBS Element Baseline Doc Reference

Requirement Comment

SKA.TEL.INFRA-SA.SMON

SMON.WIND Table 5 Wind speed conditions for operating of Dish

INFRA to provide masts for wind sensors; actual sensors are TBD (to be included in ICDs in Stage 1)

SMON.WIND 16.1.5.3 Weather stations Utilise MeerKAT weather stations and add additional weather stations for SKA1 (INFRA only responsible for infrastructure related to weather stations)

SMON.STI Not stated STI System Assume current system on site will be expanded with 3rd antenna added

SMON.RFI Not stated RFI Monitoring systems Assume current on site systems will be used and expanded. INFRA to provide power, infrastructure, but actual systems are to be defined in Stage 1 (to be included in ICDs)

SKA.TEL.INFRA-SA.POWER

POWER Tables 22,23,24,25

CSP Power requirement The driver is the 250 racks for non-imaging (i.e. pulsar search). The SKA1 Baseline option as well as the optimised option has been considered. To be agreed via ICDs

POWER Not stated MGR,SDP,SADT Power requirement

Assumptions that have been made in response to the RfP to be agreed via ICDs in Stage 1

POWER Not stated DSH Power requirement Assumptions made in response to the RfP to be agreed via ICDs in Stage 1

POWER.GRID Para 16.1.1.2 (RSA) Provision of Power Re-use MeerKAT grid power supply; expand as required OR build new 132kV Line depending on Load (See above)

POWER.RETC Para 16.1.1.1 (RSA) Power Reticulation Re-use MeerKAT power reticulation and expand as required



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Requirement Comment

POWER.RETC Not stated Site Complex Power Re-use MeerKAT power provision to Site Complex and expand as required

POWER.RETC Para 16.1.3 Power Facility Re-use MeerKAT facility and expand as required using spare capacity already planned

POWER.RETC Not stated Antenna Core Array Reticulation

Re-use MeerKAT existing infrastructure and expand as required for additional 190 antennas

POWER.RETC Not stated Antenna Spiral Array Reticulation

Power to be provided by existing Eskom rural over-head power lines

POWER.RETC Not stated Construction Camps Power supply

Re-use MeerKAT infrastructure (power supply sufficient for SKA1)

POWER.RETC Not stated Power back-up requirements

Re-use MeerKAT back-up supply and expand as required using spare capacity

SKA.TEL.INFRA-SA.ACC Access (Roads)

ACC 16.1.4 Access (Roads) Re-use MeerKAT, expand as required

ACC.PROV Not stated Provincial Road from Carnarvon to Site

It is intended to upgrade the gravel road to a

surfaced standard.

ACC.AP Not stated Basic Farm roads to SKA1 Antennas

Re-use MeerKAT basic farm network and expand as required.

ACC.AP Not stated Platforms Add additional platforms for SKA1 antennas

ACC.AS 16.1.5.2 All weather landing Strip Re-use MeerKAT landing strip for SKA1

SKA.TEL.INFRA-SA.WAS Water and Sanitation

WAS 16.1.5.1 Water and Sanitation

(Construction camps)

Re-use MeerKAT water and sanitation infrastructure and expand for SKA1

WAS 16.1.5.1 Water and Sanitation

(Site Complex)

Re-use MeerKAT existing infrastructure

Not stated Water

(Road and Construction)

Utilise existing boreholes for MeerKAT and add additional boreholes for SKA1

SKA.TEL.INFRA-SA.BLDS Buildings

BLDS.SBASE 16.1.3 Klerefontein Support Base Re-use MeerKAT buildings. Expand as required, depending on requirements from Concept of Operations and Logistic Support Analysis

BLDS.SPLEX 16.1.3 Site Complex Re-use MeerKAT, expand as required

BLDS.KAPB 16.1.3 and

Appendix B

Central Signal processing facility

Option 1: Expand KAPB with RFI shielded containers to house additional racks

Option 2: Optimise the use of the existing facility within the growth margin (work required in Stage 1 to confirm power requirement to racks; number of racks and cooling requirement)

BLDS.CSHED Not stated SKA1 Container Shed Option 1: – this option is required to meet the requirements as per Appendix B of SKA1 Baseline document

BLDS.CAMP 16.1.3 Construction Camps Re-use MeerKAT construction camps

BLDS.HQ 16.2 Cape Town HQ Building Option 1: Lease additional space for SKA1 in current building or closely located building

Option 2: New Land and Building



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Requirement Comment

SKA.TEL.INFR-SA.FOUND - Antenna Foundations

FOUND 8.2 Array Configuration

(Position of Antenna Foundations)

Positions based on SKA1 baseline document. First-round optimisation done taking topography and EMC aspects into account. Further discussion and work is required on the configuration during Stage 1 by the Configuration Working Group

FOUND Table 6 Dish Size The SKA1-mid telescope antennas will be a mixed array of 64 13.5m diameter antennas for the MeerKAT array and 190 new 15m SKA1 antennas

FOUND Not stated Antenna Foundation loading and other requirements

Assumptions made based on SSG and MeerKAT. To be confirmed in ICDs during Stage 1.

SKA.TEL.INFRA-SA.COMMS - Communication Systems

COMMS.LAN Not stated LAN System Re-use MeerKAT Local Area Network and expand as required. Interfaces with SADT to be agreed in ICDs as part of Stage 1

COMMS.BMS Not stated BMS System Re-use MeerKAT Building Management System and expand as required for additional power and ancillary equipment

COMMS.BMS Not stated Emergency Communications Radio System

Re-use MeerKAT emergency communication network and expand as required for coverage at spiral arms

SKA.TEL.INFRA-SA.VEH – VEHICLES

VEH.BAK Not stated Additional Bakkies Additional bakkies (utility vehicles) will be required for SKA1.

VEH.TRANS Not stated Additional People Transporters

Additional People Transporters will be required for SKA1.

VEH.MAIN Not stated Additional Maintenance Vehicles

Existing MeerKAT maintenance vehicles will be utilized for SKA1. Additional maintenance vehicles/equipment will be required for SKA1.

SKA.TEL.INFRA-SA.SEC - Site Security

SEC Not stated Site Security Existing provision of security will be utilized for SKA1 and expanded

Data Processing on site versus Cape Town

As per Section 2 of Applicable Document [AD 1] – SKA1 Baseline Design, it lists the requirement for the Science Data Processor Centre or SKA1-mid Computer Centre to be in Cape Town. It is stated

that signals from the dishes will be transported to a central signal processing building (i.e. Karoo Array Processor Building) where they will be divided into narrow frequency channels and cross-

correlated with each other. Output data from the correlator will be transported to the Science Data Processor Centre in Cape Town. SKA SA undertook trade-off studies as part of the Concept Design

for MeerKAT on the proposed location of the Array Processor for MeerKAT. Three options were

considered, namely 1) On site at the Losberg Site Complex; 2) at the Klerefontein Support Base and 3) Split between the Site Complex and Klerefontein. At that point in time (2009), 5 Tbit/s raw data

needed to be transported between site and Klerefontein. Based on the number of transponders (160) required between the Site and Klerefontein, the capital cost of either splitting the Array

Processor between Site and Klerefontein or locating the Array Processor at Klerefontein was found to

be unfeasible from a cost point of view. It would be completely unfeasible from a capital cost based on this modeling to consider locating the Array Processor for MeerKAT in Cape Town.

A similar trade-off study was undertaken by SKA SA in response to the SSG as part of the Site Bid (Reference can be made to Annexure G.15- SKA SA Data Transport Costs – SSG Report). This study

confirmed that it would cost € 435,459,127 more to transport 400 Tbit/s of data to the Super



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Computer in Cape Town as opposed to processing data on the SKA site. The recommendation for on-site data processing was further supported by the Site Options Working Group (SOWG).

The SKA SA is still of the view that transporting 27 Tbit/s of data between Site and Cape Town will be too costly for SKA1. Further work will be required between the INFRA SA Consortium and the SaDT

Consortium during Stage 1 to align and confirm requirements and associated costs to reconfirm this

recommendation.

The relevant technical skills have and will be employed by the SKA SA to maintain the Karoo Array

Processor Building on-site. The same skills will be required to maintain SKA1 facilities. These skills include the Site Manager; Data Centre Manager (based in Cape Town and travelling to the Karoo);

Electrical and Mechanical Technicians; IT technicians and configuration engineers; Specialist

Contracted Engineers as and when required (Government licensed specialist engineers in terms of the Occupational Health and Safety Act); general maintenance and cleaning staff. The support staff will

stay in Carnarvon.

Based on the above considerations, two options have been considered for the data processing on

site, namely:

Option 1: Utilisation of the existing Karoo Array Processor Building and provision of a new

SKA1 Container Shed housing RFI-shielded container to accommodate additional racks. The

RFI-shielded containers will be supplied by the pulsar timing group (to be confirmed in Satge

1 as part of the ICD). This is seen as an interim solution until the Science Data Processor

Centre is built for SKA2;

Option 2: Utilisation of the existing Karoo Array Processor Building.



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6. Technical response

6.1. SKA.TEL.INFRA-SA.SMON – Site Monitoring

6.1.1. SMON.WIND - Site Monitoring – Wind Sensors

It is anticipated that the Site Monitoring Equipment will consist of the following:

Wind Sensors, WBS: SKA.TEL.INFRA-SA.APF.SMON.WIND;

The Site Test Interferometer (STI) , WBS SKA.TEL.INFRA-SA.APF.SMON.STI;

RFI Monitoring systems, WBS SKA.TEL.INFRA-SA.APF.SMON.RFI.

There is a wind sensor installed on a 10m pole mast at the KAT-7 radio telescope. Reference can be

made to Image 1.

For the MeerKAT phase, three additional wind sensors will be installed in the core area on 10m high pole masts, with optic fibre connections from the closest antenna. Image 2 shows one of the pole

masts and the optic fibre sleeves.

Image 1: KAT-7 Wind Sensors

Image 2: MeerKAT Pole Mast

The Wind sensor fitted to the mast is shown in Image 3:

Image 3: Wind Sensor



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For SKA1, it is assumed that there will be additional wind sensors in the spiral arms (2 per arm) as

well as 2 additional sensors in the SKA1 core area.

The interface between the Infrastructure sub-element and the telescope sub-element will be

documented in the relevant ICD.

a. This sub-element will consist of the following:

i. 2 x Wind sensors per spiral arm: i.e. 6;

ii. 2 x Core sensors (additional to MeerKAT);

iii. Total number required = 8.

b. 1 x Foundation (same design as MeerKAT);

iv. 1 x 10m high sectional pole mast (same design as MeerKAT);

v. 1x Earthing and lightning protection (same design as MeerKAT);

vi. The 100m of 40mm Fibre ducting from the closest antenna to the wind sensor must be planned for by the SaDT Consortium;

vii. 200m of 3 phase 400V power cable (10mm) from closest mini-substation to the wind sensor;

viii. The optic fibre sleeve and Power cable should be co-located in a 1000mm deep

common trench.

The responsibility of supplying the 8 wind sensors (actual equipment) will be agreed upon with the

SKAO and defined in the relevant ICD.

6.1.2. SMON.STI – Site Monitoring – STI System

The STI system was developed by the Jet Propulsion Laboratory, California Institute of Technology

and deployed to the site as part of the SKA Site Bid site measurement campaign.

The system consists of two sensor units, underground fibre cables and an electronic rack. Image 4

shows one of the STI sensors deployed on the MeerKAT/SKA site. Image 5 shows the STI electronics

rack that is fitted inside the RFI screened CMC container.

Image 4: STI Sensor Unit as deployed to Site Image 5: STI Electronics that is fitted inside the CMC container



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It is assumed that the SKA1 requirement will be to provide a third sensor unit.

The Infrastructure element will provide the following:

Foundations for the sensors (1m x 1m x 500mm);

Connection box and fibre splice dome;

Optic fibre duct (estimate 300m) which will be provided by the SaDT Consortium;

200m Optic fibre cable to be provided by the SaDT Consortium;

200m Common trench which houses the power cable and optic fibre cable;

Electrical Power (3 phase, 4 wire, 400v, 300m).

The upgrade of the STI system will be done by the SKAO. The site monitoring system will be provided by JPL.

6.1.3. SMON.RFI – Site Monitoring – RFI System

RFI Monitoring equipment includes the following:

RFI monitoring trailers;

Portable RFI monitoring equipment;

Fixed RFI monitoring equipment.

Image 6 shows the RFI monitoring trailer being deployed on site.

Image 6: RFI Monitoring Trailer

Image 7 shows some of the portable RFI monitoring equipment currently being used on site.

Image 7: RFI Monitoring Equipment



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For SKA1 it is assumed that a permanent RFI monitoring station will be established on the Losberg Hill, which is closely located to the current MeerKAT webcam installation.

The Infrastructure element will provide the following:

Foundation (same design as the MeerKAT webcam);

Lattice mast (same design as MeerKAT) but 10m in height;

Earthing and lightning protection (same as MeerKAT);

100m 40mm Optic fibre sleeve from current webcam position to RFI monitor position which

will be provided for by the SaDT Consortium;

100m 3 phase 400V power cable (10mm) from the current MeerKAT webcam position to the

RFI monitor position.

The RFI monitoring equipment including antennas will be provided by another Consortium / telescope

sub-element.

The interface between the infrastructure and telescope elements will be documented in the relevant ICD.

Technical Risks and proposed mitigation measures

Reference can be made to Reference Document [RD 2] – INFRA SA Risk Register which describes the

technical risks and proposed mitigation measures for this sub-element.

Capital, Operational and Maintenance Costs

Reference can be made to Reference Document [RD 1] – INFRA SA Cost Breakdown Structure for the

capital costs applicable to this sub-element.



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6.2. SKA.TEL.INFRA-SA.POWER – Infrastructure Power

Introduction

The aim of the INFRA SA Consortium is to provide the most reliable power network that meets SKA1

requirements at the most economical life-cycle cost. Various options will be considered, amongst which are the utilisation of the existing power infrastructure implemented for the MeerKAT telescope

and the provision of a new 132kV grid power connection as developed for the Site Bid submission. Optimisation requirements to enable the implementation of these proposals will be identified.

In order to meet the MeerKAT power requirements, SKA SA have constructed a 33kV extension to the

existing Eskom Karoo 66kV/22kV substation, and constructed a 33kV powerline from Karoo Substation to the SKA Core site, with a length of approximately 110 kilometres. The capacity of this

point of supply is limited, with this initial proposal identifying some of the possible SKA1 estimated power requirements that could be considered for optimisation in order to reduce the overall SKA1

power capacity requirement to the capacity which could be supplied off the existing infrastructure.

One alternative identified here for consideration is the implementation of the previously developed option of a new 132kV grid connection. Stage 1 will consider these plus other options, followed by a

down-select process to be taken forward and developed in Stage 2.

This section describes the Power sub-element and includes:

a. The Power requirement, including reference and assumptions;

b. The MeerKAT power system (to be re-used / expanded for SKA1);

c. The implications of growth in load from MeerKAT to SKA1;

d. The SKA1 power system design options, identified as basis for costing:

i. Option 1 – As per the SKA1 Baseline Design Document [AD 1];

ii. Option 2 – Optimised for use of MeerKAT power system.

e. Verification of SKA1 Power system.

Power Requirement - Function of the Power sub-element

The main function (i.e. critical function) of the Infrastructure Power sub-element is to supply electrical power to the following:

a. The Telescope Antennas (DSH element) both in the core area and the spiral arms;

b. The Telescope processing and control elements (CSP, SDP, MGR) in the Processing facility;

c. The Signal and Data Transport element (SADT);

d. The provision of power to the cooling of CSP, SDP, MGR and SADT racks in the processing facility;

e. Other telescopes (KAT-7, PAPER and C-BASS).

A secondary function of the Infrastructure Power sub-element is to supply power to the following:

f. Site Monitoring systems (wind sensors, STI, RFI monitoring);

g. The various Buildings and Construction Camps (lights, power sockets, etc.);

h. The pumps etc. of the water and waste treatment systems;

i. The on-site communications systems (LAN, BMS and Radio systems).



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Power Requirement – Load Requirement

Table 2 provides a summary of the power load requirement for SKA1:

Table 2: Summary of SKA1 Power Load Requirement

Element / Sub-element Power requirement

[kVA] Reference / Assumption

Dis

h

64 MeerKAT + 190 SKA1 Dishes 3 747.0 Estimated load of 14.75kVA per dish

Source is initial estimates from Dish Consortium, to be

confirmed during Stage 1

Sub. Dish 3 747.0

Pro

cess

ing F

aci

lity

CSP element 2 629.4 [AD 1] - SKA1 Baseline Design document, tables

22,23,24 and 25

MGR element 40 Source is initial estimates from MGR Consortium, to be


SDP element 300 Source is initial estimates from SDP Consortium, to be


SADT element 31.3 Source is initial estimates from SADT Consortium, to

be confirmed during Stage 1

INFRA-SA.COMMS

LAN and BMS sub-elements

12.5 Re-use MeerKAT systems

INFRA-SA.BLDS.KAPB

Cooling for processing facility

1 269.7 Based on design of MeerKAT HVAC system

Sub. Processing facility 4 282.8

Oth

er

KAT-7 and PAPER 67.5 Based on MeerKAT estimates

Buildings and Construction Camps 619.9 Re-use MeerKAT systems

Sub. Other 687.4

Total Power Requirement 8 716.7

Power Requirement – Quality of Power and Redundancy

Table 3 provides a summary of the Quality of Power and Redundancy requirements for SKA1:

Table 3: Quality of Power and Redundancy Requirement

Power Parameter Requirement Reference / Assumption

Nominal Voltage

(for Dish and other elements)

400V (3 phase) South African Standard used on MeerKAT

To be confirmed during Stage 1

Voltage tolerance

(drop or rise)

± 5% ESKOM Standard used on MeerKAT


Nominal Power factor


0.8 Assumption based on MeerKAT


Redundant power for dishes Full redundant power source

(i.e. Primary and standby)

Assumption based on MeerKAT


Redundant power for CSP, SDP, MGR

and SADT

Full redundant power source

(i.e. Primary and Standby)

Assumption based on MeerKAT


Uninterruptable (UPS) power for Dish Not required MeerKAT dishes require UPS power

SKA1 requirement to be confirmed during Stage 1



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Power Parameter Requirement Reference / Assumption

Uninterruptable (UPS) power for CSP,

SDP, MGR and SADT

UPS power required Assumption based on MeerKAT


MeerKAT Power System – Description of Current System

The current MeerKAT power system consists of the following sub-elements:

a. The Prime power source from ESKOM (INFRA-SA.POWER.GRID), including:

iii. The ESKOM 66kV supply to the Karoo substation;

iv. The Karoo substation upgraded for MeerKAT;

v. The 33kV grid power line.

b. The backup and UPS power source at the KAPB facility (INFRA-SA.POWER.KAPB):

vi. 33kV Transformers and switchgear;

vii. The Diesel Rotary UPS systems (N+1 redundancy);

viii. The 22kV Transformers and switchgear;

ix. 400V feeds to the processing facility (dual redundant).

c. The reticulation to the Dishes (INFRA-SA.POWER.RETIC):

x. 22kV network to the Dishes (dual redundant feeds);

xi. The 22kV/400V minisubs (maximum 5 dishes per mini-substation).

Table 4 shows some of the sub-elements of the MeerKAT Power system:

Table 4: Sub-elements of the MeerKAT Power System

Karoo 66kV/33kV Substation (vicinity Carnarvon) 33kV grid line with Voltage Boosters

22kV/400V Mini-substation (part of on-site electrical reticulation)



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MeerKAT Power System - Capacity

Table 5 provides an overview of the capacity of the current MeerKAT power system:

Table 5: Capacity of current MeerKAT Power System

Power Sub-element Capacity Growth available for SKA1

PO

WER

.GR

ID

ESKOM 66kV supply

to Karoo sub station

The current ESKOM 66kV supply

can provide 10MVA to the Karoo

substation

The 10MVA capacity is allocated a follows:

2.5MVA capacity for local towns and farms

7.5MVA capacity available for SKA1

(upgrades are possible but need to be investigated)

Karoo substation The Karoo substation was upgraded

for MeerKAT with 2 x 5MVA

66kV/33kV transformers, i.e. total

capacity of 10MVA

5MVA capacity available for SKA1/MeerKAT

This can be increased to 10MVA (to be confirmed during

Stage 1) capacity by running two transformers in parallel,

but the provision of a possible spare transformer for

redundancy / repair time needs to be investigated during

Stage 1

33kV Grid Line The new 33kV grid power line

constructed for MeerKAT can

provide 4.9MVA

(limited by voltage booster required

for the length of the line)

4.9MVA available for SKA1/MeerKAT

The voltage booster design can be upgraded to provide 6

MVA capacity

PO

WER

.KAPB

Power facility The power facility has

2 x 2.5MVA transformers

i.e. total capacity of 5MVA

Full 5MVA capacity is available for SKA1/MeerKAT

Upgrades might be required, due to technical

considerations such a fault levels

Standby Power

(Diesel)

For MeerKAT, 3 x 1.25 MVA standby

generators are installed with a N+1

configuration

(i.e. 2.5MVA)

The facility design (space, busbars,

switchgear, etc) has a total capacity

of 5MVA


Uninterruptable (UPS)

Power

For MeerKAT, 3 x 1.25MVA Rotary

UPS system are fitted in a N+1

configuration

(i.e. 2.5MVA)

The facility design (space, busbars,

switchgear, etc) has a total capacity

of 5MVA


PO

WER

.RETIC

22kV reticulation to

Dishes

The MeerKAT 22kV reticulation has

a capacity of 7.6MVA

Full 5MVA capacity is available for SKA1

22kV to 400V Mini-

substations

For MeerKAT 21 x 315kVA mini-

substations are provided with a

limitation of 5 Dishes per mini-

substation

(i.e. less than 10% of total array)

It is assumed that for SKA1 up to 26 dishes (10% of

array) can be added per mini-substation. Additional mini-

substations can be added to the 22kV reticulation

network to provide the full 5MVA capacity

The 21 dishes on the spiral arms will be supplied by

existing ESKOM rural overhead power lines (new mini-

substations to be added).



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MeerKAT system - Quality of Power and Redundancy

Table 6 provides a summary of the Quality of Power and Redundancy requirements for the current

MeerKAT power system:

Table 6: MeerKAT Power System - Quality of Power and Redundancy

Power Parameter MeerKAT Value Comments

Nominal Voltage


400V (3 phase) South African Standard

Voltage tolerance

(drop or rise)

± 5% ESKOM Standard

Nominal Power factor


0.8 Power factor correction is done by the DRUPS

systems as well as reactors fitted to the mini-

substations and at the power facility

Reliability of ESKOM Power NRS 048 limits Power supply was monitored by the SKA SA and

meets the standard

Redundant power for dishes Full redundant power

source (i.e. Primary and

standby)

Primary source is ESKOM

Standby is Diesel Generators

Diesel Generators have N+1 redundancy

Redundant power for processing facility

(including cooling)

Full redundant power

source (i.e. Primary and

Standby)

Primary source is ESKOM

Standby is Diesel Generators

Diesel Generators have N+1 redundancy

Processing facility has dual redundant feeds (A bus

and B bus)

Uninterruptable (UPS) power for Dish Full UPS to all dishes Rotary UPS systems integrated with Diesel

Generators

N+1 redundancy

Uninterruptable (UPS) power for

processing facility (including cooling)

Full UPS Rotary UPS systems integrated with Diesel

Generators

N+1 redundancy

Growth from MeerKAT to SKA1 - Overview of Implications

Table 7 provides a high level summary of the system design implication of the load growing from MeerKAT to SKA1:

Table 7: Power System Design Implication of the Load growing from MeerKAT to SKA1

Project

Phase Load Growth

System design Implications

POWER.GRID POWER.KAPB POWER.RETIC

MeerKAT Up to 2.5MVA Nil Nil Nil

SKA1

2.5MVA to 5MVA Upgrade Voltage Boosters Add Rotary UPS systems Add Mini-substations

5MVA to 6MVA Upgrade Voltage Boosters

Spare 5MVA transformer at

substation

Add Rotary UPS systems

Replace 33kV/22kV

Transformers

Add Mini-substations

6MVA to 8.7MVA Build new 132kV power

line from KRONOS

Add Rotary UPS systems

Replace 33kV/22kV

Transformers

Add Mini-substations



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SKA1 Power System - Overview of Defined Options

Two options have been identified for the SKA1 power system:

a. Option 1 (SKA1 Baseline Design option) – Upgrade to the MeerKAT power system in order to meet the 8.7MVA maximum power demand;

b. Option 2 (Optimised Option) – Utilise the 5MVA available by optimisation of the power load

requirement.

In addition to these two options, a possible design solution for the supply of power to the Dishes in

the spirals is also described.

SKA1 Power System - Description of Option 1 (SKA1 Baseline Design Option)

In order to provide the maximum demand of 8.7MVA (refer Table 2), the following option has been

identified based on the recommendations in the SSG report:

a. Additions to the KRONOS substation;

b. New 132kV line from KRONOS substation;

c. New Astronomy substation;

d. Changes to existing 33kV grid power line.

Figure 1 shows the ESKOM bulk power infrastructure in relationship to the SKA site, including the CUPRUM, KRONOS and KAROO substations:



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Figure 1: ESKOM bulk power infrastructure in relationship to the SKA site



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Image 8: ESKOM bulk power infrastructure in relationship to the SKA site – Aerial view



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Table 8 provides a summary of upgrades to the Power system for this option:

Table 8: Summary of upgrades for Option 1

Power System – Sub-element Upgrade for Option 1 Reference

Upgrades to KRONOS

400kV/132kV transmission station

400kV/132kV (2 x 250MVA) transformer

bay expansion with transformers

Drawing

107102–SSG–ELE–0010.

New 132kV power line for 110km from

KRONOS to ASTRONOMY

New monopole structure, overhead power

line 110km from KRONOS to ASTRONOMY

Drawing

107102–SSG–ELE–0010.

New ASTRONOMY Substation The proposed new 132kV/33kV Eskom

substation “Astronomy” is located adjacent

to the proposed new Site complex and

Processor building (part of SKA2)

Modification to 33kV grid power line Modifications to feed existing MeerKAT

33kV line from the new ASTRONOMY

substation



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Figure 2 shows the proposed layout of the new ASTRONOMY substation:

Figure 2: Proposed Layout of new Astronomy Substation for Option 1



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SKA1 Power System - Description of Option 2 (Optimised)

Table 9 provides an overview of the opportunities for optimisation of the power load requirements.

These are initial estimates from the INFRA SA Consortium and need to be confirmed with the various elements such as the DISH, CSP, etc. during Stage 1 of the Pre-Construction design phase and

documented in the ICD documents.

Table 9: Opportunities for optimisation of Power Load Requirements

Power Load

Sub-element

Current Estimated

Value Opportunity for Optimisation

DISH element

Total Power

14.75kVA per dish

254 dishes

3 747kVA total

For each kVA of power optimisation per dish, the total load will reduce by

254kVA.

Initial discussion with the DISH consortium indicates that a load of 12kVA

per dish is achievable, i.e. total reduction of 424kVA can be

investigated.

DISH element

Power to Spirals

14.75kVA per dish If 21 dishes in the spiral arms are supplied from the rural ESKOM supply

rather than the KAPB facility, a saving of 310kVA can be investigated.

The backup power to stow the dish during high wind conditions needs to

be investigated during Stage 1.

CSP element

Non-Imaging (Pulsar

search)

250 racks

20kW per rack (max)

8kW per rack (avg)

2 500kVA total

Initial discussions with the CSP Consortium indicate that a reduction to

40 racks with 6kW each can be investigated.

This reduces the power for this element from 2.5 MVA to 300kVA, i.e. a

saving of 2 200 kVA.

Processing facility

Cooling

Power for cooling 315

racks

1 269kVA total

If the CSP non-imaging is reduced as indicated above, the power for

cooling can be reduced to 344kVA, i.e. a saving of 926 kVA

Construction facilities

and security

196kVA Remove this from the Rotary UPS supply (but keep on ESKOM supply)

Rotary UPS Load

(optimised)

5 000kVA available The total opportunity for Rotary UPS load optimisation is 4 056kVA

i.e. reduce the Rotary UPS load from 8 717kVA to

4 661kVA

Grid Power Line Load

(optimised)

6 000kVA available The total opportunity for grid line load optimisation is 3 860kVA

i.e. reduce the Rotary UPS load from 8717kVA to

4 857kVA

Discussion of Option 2

Table 9 shows that with the proposed optimisation of the SKA1 load, power can be supplied from the current MeerKAT power system.

During the Stage 1 design, the following needs to be investigated in further detail:

a. The opportunities for load optimisation from other SKA1 elements (DISH,CSP etc);

b. The opportunities for load optimisation from the INFRA SA elements (Buildings etc);

c. Technical design aspects such as voltage drop, power factor corrections, fault currents etc.

SKA1 Power - Supply of Power to Antennas in the SKA1 Core

As part of the existing KAT-7 and MeerKAT radio telescope, a Random Electrical Reticulation design

approach was followed to provide power from the Power building at the Site Complex to the antennas.

This design allows for an optimised cable route path for both MV and LV voltage cables which are

clearly marked by cable markers every 200m and GPS coordinates. The electrical reticulation design also included the provision of optic fibre ducting installed in a common power/optic fibre trench to

reduce capital costs.



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22 Mini-substations have been provided on site for the MeerKAT antennas.

The typical schematic presentation of the MeerKAT Distribution Network is indicated in Figure 3. The

same design philosophy will be followed for the SKA1 design.

Figure 3: Typical Schematic – Distribution Network

No additional MV feeder cables from the Power building to the SKA1 core antennas will be required as the existing MeerKAT MV ring network can accommodate the SKA1 loading requirements.

The current MeerKAT electrical reticulation network will be expanded to supply the SKA1 antennas

through the provision of additional MV cables to the antennas. Due to the density in the MeerKAT/SKA1 core, it is foreseen that existing MeerKAT 315kVA mini-substations will be utilised to

accommodate the SKA1 loading requirements. Some of the mini-substations will need to be upgraded to 500kVA units.

Reliability, Availability and Maintainability (RAM) modelling of the SKA1 electrical network will be

executed as part of Stage 1. This needs to be done to confirm the maximum number of SKA1 antennas which could be out of order due to fault conditions on a specific mini-substation. For SKA1

costing purposes, it has been assumed that there will be 1 mini-substation/26 antennas.

Reference can be made to the following Drawings in Annexure A of this document:

Power.Retc.EP-0103 – Proposed New SKA Phase 1 Dish Positions Sheet 1 of 2

Power.Retc.EP-0104 – Proposed New SKA Phase 1 Dish Positions Sheet 2 of 2

Power.Retc.EP-0108 – Electrical Reticulation Random Layout

SKA1 Power – Supply of Power to Antennas in the Spiral Arms

The Spiral Arms antenna array reticulation design was divided into two sections:

a. The first section’s design allowed for some antennas on the spiral arms to be reticulated by

extending the existing KAT-7/MeerKAT electrical reticulation network;

b. The second section’s design allowed for the 21 antennas on the Spiral Arms to be supplied from existing Eskom rural over-head power lines. This will be part of the 22kV section of the

KAROO substation.

c. A 2km separation distance was allowed for between any antennas and overhead line

networks, based on SPDO methodology used by the Configuration Task Force (CTF) for optimisation of the SKA configuration in response to the SSG / site group Request for

Information, 2011.

Figure 4 shows the proposed connection of the antennas in the Spiral Arms to the existing Eskom 22kV rural overhead power lines:



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Figure 4: Connection of the antennas to the existing Eskom 22kV overhead power lines



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Image 9: Connection of the antennas in the Spiral arms to the existing Eskom 22kV overhead power lines – Aerial view



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SKA 1 Electrical Reticulation and Rotary UPS Maintenance considerations

The Power Building was designed to serve the role of a central substation / hub - a single point to

which the utility (Eskom) supply can connect and from which KAT-7, PAPER and MeerKAT antennas and ancillary loads are subsequently fed from. In addition to offering this central distribution and

control feature, an arrangement of diesel Rotary uninterruptible power supplies (DRUPSs) within the

building offer continuity of supply to the MeerKAT and existing loads.

The building is currently supplied via the Karoo substation at 33kV through an overhead line feeder

(Hare conductor) and underground cable (50 mm² three cored XLPE) for the last few hundred meters.

Inside the Power Building the 33kV is stepped down to 22kV and 400V, with voltage stepping being

implemented via two sets of distribution transformers, located inside the Transformer Room:

Two 2,5 MVA 33kV/22kV transformers (designed to operate in parallel) - 5 MVA Installed

Capacity;

Two 1,6 MVA 22kV/0,4 kV transformers (designed to operate un-paralleled) - KAPB and local

site load.

For MeerKAT, three Rotary UPS units are installed.

Each of these three Rotary UPSs are rated at 1 MW / 1,25 MVA (totalling 3 MW / 3,75 MVA); but their

configuration while powering the MeerKAT installation will be “N+1”, meaning only 2 MW / 2,5 MVA will be available for use as one unit will be in hot standby at all times (to allow for maintenance or

single unit failure without shutting down or load shedding).

The MeerKAT Rotary UPS system is modular of nature, meaning that additional Rotary UPSs can be

installed in parallel with these three in order to increase the total UPS output rating (provided they are

of the same size and manufacture).

For this purpose physical space has already been allocated inside the Power Room for the placement

of an additional two units, making physical allowance thus for an increase in the total power output of the Rotary UPS system from the current (MeerKAT) output of 3 MW / 3,75 MVA (or 2 MW / 2,5 MVA

in “N+1” mode) up to a total of 5 MW / 6,25 MVA (or 4 MW / 5 MVA in “N+1” mode) - such outputs available in “conditioning” i.e. non-emergency mode as well as “standby” i.e. diesel-powered mode.

The Rotary UPS installation can with minimal design and installation effort be expanded to five of

1,25MVA units, offering thus Installed Capacity of 6,25 MVA and Firm Capacity of 5 MVA.

Each 1,6 MVA transformer is currently being installed for the MeerKAT feed into a bus section of the

main low voltage distribution board. Each bus section of the board, being rated at 2 500 A, will be able to supply the full anticipated Losberg Site Complex load (MeerKAT data racks and cooling). This

redundancy is to be implemented via dual feeds from this main board to the sub-distribution boards,

each feeding in turn the racks and rack air conditioning systems.

In terms of building structures, for MeerKAT, the Power Building section of the KAPB is currently

being constructed to consist of three switch/control rooms, a power (generator) room and a transformer room (plus two passages serving as intake and exhaust ducts).

Power Room: this room will house the Rotary UPSs, generator transformers, Rotary UPS

chokes, and the diesel day tanks for up to 5 Rotary UPS units;

MV Room (Domestic): this room will house “Domestic” MV switchgear (33kV and 22kV panels

not associated with the Rotary UPS system). The switch panels in this room are all of the fixed

pattern gas (SF6) insulated busbar type (with vacuum circuit breakers);

Transformer Room: this room will house the distribution transformers (two 1,6 MVA and two

2,5 MVA transformers), as well as a Rotary UPS auxiliary transformer (500 kVA), and zigzag-

type earthing transformer with 140 Amp neutral earthing resistor (space is available for the

installation of an additional resistor should the need arise);

Control Room: this room will house the main 400 V distribution panel to the KAPB building

(from whence the KAPB data centre loads as well as all 400 V site loads are fed), as well as

the UPS system’s control panels;



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UPS MV Room: this room will house the 22kV switchgear of the Rotary UPS system. The

switch panels in this room are all of the withdrawable air insulated busbar type (with SF6

circuit breakers).

Although the Rotary UPS system is inherently modular, some physical, functional and safety

constraints precludes the extension of the MeerKAT DRUPS system to more than 5 units. The

constraints being amongst others the dimensions of the UPS MV, Control and Transformer rooms inside the building, the dimensions of the trenches, electromagnetic compatibility, and current ratings

of installed equipment.

Option 1 (SKA1 Baseline Design)

In order to increase the current Power building’s capacity to accommodate this maximum site loading

for the SKA1 Baseline Design requirement, the following changes are proposed:

Increase the size of the main 33kv/22kV transformers;

Reserve the Rotary UPS units inside the KAPB for 400 V KAPB and site complex loads;

Provide new additional containerized backup power to the 22kV underground cable networks

supplying the antennas.

This is proposed to be implemented as follows:

Install two new 5 MVA 33kV/22kV oil type transformers outside the building;

Install four containerised Rotary UPSs to supply the 3,4 MVA to the antennas (1,25 MVA units



fire detection, etc.;

Install new DRUPS auxiliary transformer to supply its ancillaries;

Install an additional 1,25 MVA Rotary UPS inside the Power Building, to supply the 3,8 MVA to

the local Losberg site loads including data centre components (thus the 400 V loads);

Remove the existing 2 x 2,5 MVA 33kV/22kV transformers from the building;

In their positions install two new 2 MVA 22kV/0,4 kV transformers - these to supply the RFI-

shielded containers containing the additional racks which cannot fit inside the KAPB via a new

3 000 A dual bus LV panel outside the building;

If needed (in order to distribute loads between the two installations) some of the site complex

loads (e.g. construction sheds) can be moved over from the KAPB LV supply to the antenna

supply, using old transformers.

Option 2 (Optimised solution)

In order to increase the current Power building’s capacity to accommodate a maximum site loading

indicated in the alternative solution, the following network changes are proposed:

Install an additional two 1,25 MVA Rotary UPS units inside the provided space inside the

Power Building.

By implementing either option, all loads listed will be supplied with conditioned power and all of the

site reticulated antennas would have the function of stowing when needed. All connected loads will be

independent of external grid faults and would operate normally.

Availability and reliability of the Rotary UPS units

The Rotary UPS system will offer an automatic and break-free changeover from the mains (Eskom) power supply to diesel generator power when the former fails. Furthermore:

The Rotary UPS system can be programmed to offer a redundancy of N + 1 for the maximum

power required by the SKA1 installation;

The reliability of the complete facility is estimated to have a Mean Time Before Failure (MTBF)

of more than 10,000 hours;



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The N + 1 redundancy configuration will allow for maintenance to be done on any one of the

Rotary UPS units without interruption of power supply to the loads;

Major functions of the medium voltage equipment and the Rotary UPS units will be relayed to

and thus monitored by the building management system (BMS) which is currently in the

process of being installed;

The existing bulk diesel storage tanks (three tanks containing 23 kilolitre each, located next to

the KAPB building), plus the new day tanks which are proposed to be installed or in the

process of being installed (one 1000 litre day tank per Rotary UPS), offering a total capacity of

just over 70 kilolitres, will allow the site to run at full load for over 48 hours for Option 2

(5MVA) - the fuel consumption of 5 machines at full load in N+1 mode being 1 450 litres /

hour. However, for Option 1 (7,8 MVA), in order to provide 48 hours backup another bulk tank

should be installed in order to increase the total capacity to 106 kilolitre (consumption of 8

machines being 2 200 litre / hour in N+1 mode).

SKA 1 Electrical Reticulation and Rotary UPS Maintenance considerations

Electrical Reticulation components

Table 10 illustrates the South African industry standard design lifecycle of the different major electrical components as well as the typical maintenance periods:

Table 10: South African industry standard design lifecycles

Item Description Industry Design

Lifecycle Period

MTTR

(Mean Time To Repair)

Typical Maintenance

Period

3.3kV 25kVA Transformer 25 Years

Dependent on SKA Staff and

Maintenance Program

6 months – Visual

inspection

315kVA Transformer 25 Years 6 months – Oil test

SF6 Ring Main Unit – Tank 30 Years 6 months – Visual

inspection

SF6 Ring Main Unit – Switch

Mechanism 2000 Switching cycles

6 months – Visual

inspection

22kV XLPE Cables 25 Years -

LV PVC Cables 20 Years -

Rotary UPS units

Regular service intervals need to be scheduled for the Rotary UPS units. Minor services of the Rotary

UPS units will be done at the Site Complex. Once larger services, such as the replacement of bearings are required, the Rotary UPS unit will be replaced with a refurbished unit. The unit which requires

maintenance will be serviced at the Supplier’s workshop as part of a Service Level Agreement. Bypass switches allow for maintenance to be done on any one of the Rotary UPS units with no interruption to

the power supply. Maintenance on other electrical ancillary equipment includes the following:

The distribution transformers used inside the Power Building will be of the oil-free (dry) type,

thus requiring minimal servicing;

Visual inspections of all diesel pipelines, cable connections and switchgear will be required

every six months and servicing will be required every two years or less as per the suppliers’

recommendations;

Regular service intervals need to be scheduled for the air filters belonging to the Rotary UPS

ventilation system.



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6.2.1. POWER.GRID – Upgrade to Grid Power

The INFRA SA Consortium has analysed the power and data rack requirements as defined in [AD 1] –

SKA1 Baseline Design. Further modelling has been undertaken by the Consortium in consultation with other Consortia and two options have been considered for the provision of bulk power to the SKA site,

namely:

Option 1: Upgrade of the Eskom grid power network (Total load of 7 981.6kVA excluding the

antennas in the spiral arms) by:

Introducing 400kV/132kV transformation at the existing Eskom Kronos substation;

Providing new 400kV / 132kV (2 x 250MVA) transformer bays to the existing Kronos

substation;

Power will be transmitted by a newly constructed 132kV power line from the Kronos

substation to the newly proposed 132/33kV Astronomy substation located approximately

35km from the site.

Option 2: Utilisation of the existing bulk grid power supply to site (Total load of 4 857kVA with a

power factor of 0.98) and:

Replacing the existing 100A voltage boosters with new 200A units and repositioning the new

units;

Upgrading the 33kV/22kV Transformers from 2.5MVA to 5MVA.

It should be noted that the definition of requirements (power, cooling and number of racks) from

other Consortia will be a key activity during Stage 1 as the biggest cost-driver for SKA1 is related to

the provision of grid power to the site.

POWER.GRID Installation standards

Additions to the Substations and Grid line will be designed and installed to fully comply with the latest editions of all relevant South African National and selected international standards, as well as

regulations, codes of practise and guidelines, which will also form the basis of testing and acceptance.

Of these, the most relevant documentation will be:

SANS 10198-8:2007 The selection, handling and installation of electric Power cables of rating not exceeding 33kV (Part 8: Cable Laying and Installation)

SANS 62271-100 Circuit Breakers (1kV – 52kV)

SANS 1063 Earth Rods

SANS 1411-1 Earth Wire (Conductors)

SANS 10400 South African Occupational Health and Safety Act, Act No 1993 and regulations

6.2.2. POWER.RETC – Upgrade to Electrical Reticulation (MV and LV)


As per the SKA1 Baseline Design, it is estimated that the total power requirement at the Losberg Site

Complex is 4.3MVA. Calculations of the total number of processor racks required for both MeerKAT and SKA1 amount to 316 racks. In order to respond to the SKA1 Baseline Design, Option 1 is

considered:

Option 1: Utilisation of the existing Karoo Array Processor building at the Losberg Site Complex and the provision of new SKA1 Container Shed housing RFI-shielded containers to accommodate the

additional processor racks. This solution is proposed in an effort to minimise capital costs for SKA1 as an interim solution until the Science Data Processor Centre is constructed for SKA2. A further



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assumption has been made that the RFI-shielded containers will be supplied by the pulsar timing group. In addition to the above, the INFRA SA Consortium has deviated from the SKA1 Baseline

Design by assuming that the data processing will take place on site as opposed to Cape Town. The reasoning for this deviation is explained in Section 6.5.4. Should the proposed container option not be

considered feasible by the SKAO, the alternative option will be to construct a new building at the

proposed “Astronomy Complex” where the 132kV/33KV substation will be constructed (should this be required). This option has not been costed in response to the RfP.

Option 2: The INFRA SA Consortium has done further modelling on the SKA1 Baseline Design where the proposed updated SKA1 requirement was identified to be 106 processor racks in total. Based on

this modelling, the total number of processor racks for MeerKAT and SKA1 can be accommodated in

the existing Karoo Array Processor building.

For both options, the 21 Spiral Arm Antennas are supplied from existing Eskom rural overhead power

lines in the area.

Antenna Core Array Reticulation

As per the SKA1 Baseline Design, the baseline array configuration received from the SKAO was optimised by considering the local topography and EMC characteristics. Reference can be made to

[RD 6] - INFRA SA Array Layout Report in the “Reference Documents” file which forms part of this

submission.

No additional MV feeder cables will be required from the existing Power Building on site to the SKA1

antennas. The total power requirement for the SKA1 antennas is 2.8MVA.

The existing three-leg MV cable ring network provided for MeerKAT will accommodate the required

SKA1 loading requirements.

The existing on-site reticulation network will be expanded to supply the new core and outer skirt antennas with power where the MV cables will cut into the existing ring network. Most of the existing

315kVA miniature substations provided for MeerKAT can be re-used for SKA1 with some units having to be upgraded to 500kVA.

21 Antennas on the spiral arms with be supplied by existing Eskom rural overhead power lines.

It should be noted that the optic fibre design will need to be aligned with the existing MeerKAT and proposed SKA1 electrical reticulation design.

Existing Construction Camps Power Supply

The existing power and back-up supply to the Meys Dam and Losberg construction camps will be re-

used for SKA1.

POWER.RETIC Installation standards

The MV cables and mini-substations of the reticulation network will be designed and installed to fully

comply with the latest editions of all relevant South African National and selected international standards, as well as regulations, codes of practise and guidelines, which will also form the basis of

testing and acceptance. Of these, the most relevant documentation will be:

SANS 1507: Electric cables with extruded solid dielectric insulation for fixed installations (300/500V to 1 900V/3 300V)

SANS 10292: Earthing of Low Voltage (LV) Distribution Systems

SANS 10198-8:2007 The selection, handling and installation of electric Power cables of rating not exceeding 33kV (Part 8: Cable Laying and Installation)

SANS 1213: Cable Glands

SANS 60529 Enclosure IP Ratings

SANS 62271-100 Circuit Breakers (1kV – 52kV)

SANS 1063 Earth Rods



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SANS 1411-1 Earth Wire (Conductors)

SANS 60439: Low voltage switchgear and control gear assemblies

SANS 10400: South African Occupational Health and Safety Act, Act No 1993 and regulations

SANS 780 Distribution Transformers

SANS 62271-202 and SANS 1029

Miniature Substations

SANS 1874 Metal – Enclosed Ring Main Units

IEC 60354:1991 Loading Guide for Oil-Immersed Transformers

SABS 156 Moulded-case circuit-breakers

SANS 1339 XLPE MV Cable

SANS 6284-3:2007 Test Method for XLPE Cables

6.2.3. POWER.KAPB – Upgrade to KAPB Power (including DRUPS)

The Power Building was designed to serve the role of a central substation / hub - a single point to which the utility (Eskom) supply can connect and from which KAT-7, PAPER and MeerKAT antennas

and ancillary loads are subsequently fed from. In addition to offering this central distribution and control feature, an arrangement of diesel Rotary uninterruptible power supplies (DRUPSs) within the

building offer continuity of supply to the MeerKAT and existing loads.

Option 1: In terms of the SKA1 Baseline Design, the total on-site power requirement is 8.7MVA, which includes the existing KAT-7, MeerKAT and SKA1 power requirements.

In order to meet the total site requirement of 8.7MVA, the following changes will be required:

Install two new 5MVA 33/22kV oil-type transformers outside the existing Power building and

remove existing 2x2,5MVA 33/22kV transformers;

Reserve the DRUPS inside the KAPB for 400V KAPB and site complex loads and install new

DRUPS auxiliary transformer to supply its ancillaries;

Install four containerized Rotary UPSs to supply the 3,4MVA to the antennas (1,25MVA units



fire detection, etc;

Install an additional 1,25MVA Rotary UPS inside the Power Building, to supply the 3,8MVA to

the local Losberg site loads including data centre components (thus the 400V loads).

The INFRA SA Consortium has undertaken further modelling and has presented the following

alterative option:

Option 2: Re-use the existing Power Building based on the proposed amended power requirements derived from the KAT-7 and MeerKAT experience for SKA1 (5MVA) with the following addition:

Install an additional two 1,25MVA Rotary UPS inside the provided space inside the existing

Power Building.

Maintenance considerations, reliability and availability have been discussed in terms of both options provided.

POWER.KAPB Installation standards

The equipment in and around the Power Building will be designed and installed to fully comply with the latest editions of all relevant South African National and selected international standards, as well

as regulations, codes of practise and guidelines, which will also form the basis of testing and acceptance. Of these, the most relevant documentation will be:

Occupational Health and Safety Act 85 of 1993



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SANS 10142-1 (The wiring of premises)

IEC 88528-11 (Rotary uninterruptible systems).

Specific tests that will be performed include:

Check and confirm the integrity of control, signal and power wiring and terminations (visual

inspection, insulation tests, etc.);

Perform “cold” commissioning (functional checks, secondary relay injection, pressure testing,

phasing and insulation tests of incomer and feeder cables etc.);

Perform “hot” commissioning (functional testing of all breakers and interlocks after mains

energizing), simulating all possible modes of operation;

Airflow test report on the UPS ventilation system;

Sound pressure level measurements to ensure regulatory compliance.



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6.3. SKA.TEL.INFRA-SA.ACC – Infrastructure Access

6.3.1. ACC.PROV – Provincial Road from Carnarvon to Site

Functional Description of Element

The provincial access road to the core is currently a gravel road which has a high standard vertical and horizontal alignment as well as a 1 in 10 year return drainage design standard. It is intended to

upgrade the gravel road to a surfaced standard. The length of the road is 80km.

It should be noted that several of the outer stations will be accessed to a certain extent by the existing provincial and district low order gravel roads. These existing roads, (approximate length of

133km) may need to be repaired in places to provide better access, however this will be assessed during Stage 1.

Design Specification and Design Standards

The anticipated pavement design for the upgrade of the provincial access road is as follows:

The following was used for a preliminary pavement design:

2013 traffic 105 vehicles per day;

Directional split 50%;

Heavy vehicles 30%;

Allowance for 25 200 construction vehicles with 12 500 kg load each (315 000 tons of material

transported over the road);

Design life 20 years.

Using a sensitivity analysis with traffic growth between 1 and 4.5 % and E80 per heavy vehicle factor

of 2 to 3.75, an ES1 (0.3 – 1 million E80’s) pavement will be required. Assuming the use of locally

available granular material the following design is proposed:

13.2/6.7 Double seal with modified binder (SE-1, SBR);

125 C3 base using imported material from borrow pits (modified with 1.5% lime and 3%

cement);

150 in situ C4 using existing wearing course (modified with 1.5% lime and stabilized with 2%

cement).

Design Assumptions

As-built information will be used for the design of the upgrade to the provincial road.

Traffic loading on the provincial road is assumed to be 0.3 – 1 million E80’s with allowance for 25 000

heavy construction vehicles;

Maintenance Requirements

The provincial road to site needs to be maintained on a regular basis. Best practice maintenance could

possibly comprise the following actions:

Year 5 – Reseal

Year 10 – Asphalt surfacing

Year 15 – Reseal

Ad Hoc drainage clearing when required.

Ad Hoc pothole repairs.



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Material Required

A minimum of 6 borrow pits will be required (at approximately 28 000 m3 per borrow pit) for the

upgrade of the provincial road. These will need to be investigated and sourced as part of the site characterisation studies which is outside the scope of the Infrastructure and Power element design.

All new borrow pits will require the necessary mineral permits.

Identification of Technical Risks and Mitigation Strategy

Reference can be made to Reference Document [RD 2] – INFRA SA Risk Register which defines the

technical risks and proposed mitigation measures.



detailed capital, operational and maintenance costs for this sub-element.

6.3.2. ACC.AP – Basic Farm Roads to SKA1 Antennas


Reference can be made to [AD 1] - SKA1 Baseline Design which indicates that the SKA1 roads must be the same as the MeerKAT roads (basic farm roads).

As per the SKA1 Baseline Design, the baseline array configuration received from the SKAO was optimised by considering the local topography and EMC characteristics. Reference can be made to

[RD 6] - INFRA SA Array Layout Report. It is expected that the SKAO Configuration Working Group

will be refining the array configuration during Stage 1 which will be fixed (frozen) at the end of Stage 1.

The outer roads and core roads will be designed as basic farm roads with concrete drifts at critical drainage crossings. The basic farm road standard comprises clearing and grubbing of the route with a

grader and placing a 200mm compacted gravel layer on top of natural ground level. Earth cut off drains and channels cut by a grader will be used to channel storm water flow to the concrete drifts to

minimise erosion of the gravel layer. The drainage is relatively informal and basic and the level of

service is lower than that of the Provincial access road. There will be approximately 107 km of farm roads. Please refer to the road network layout drawings included as in Annexure A (Table 11).

Image 10: Typical Farm Road (existing MeerKAT road)



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All platforms at the antennas will be raised by a minimum of 300 mm. The platforms are 100mm higher than the farm roads in order to provide a suitable platform for vehicle turning movements and

to enable better stormwater management. Platform sizes have been designed to accommodate the turning circles of the existing SKA SA dish transporter and a maximum dish dimension of 15.5m. (Note

that this is an assumption).

Image 11: Typical platform around the Antenna Foundation for MeerKAT

The SKA SA has a Section 21 (c) and (i) Water Use License in terms of the National Water Act, 1998.

This license is applicable to the MeerKAT road network and any upgrades that may come about in the future on the farms Meys Dam and Losberg.


Geometry

Horizontal Design

Design speed : 40km/h

Absolute minimum design speed : Crawling speed

Min Radius : 80 m

Absolute minimum Radius : 24 m

Curve length : Not applicable.

Max Super-elevation : 4%

Vertical Design No vertical design standard was used on the farm roads.

Platforms

Platform radius : 24 m

Bell mouth Radius (Truck route) : 24 m

Bell mouth Radius (Maintenance route) : 5 m

Cross section

Roadway width : 5 m

Minimum Cross-fall : 4%

Fill Slopes : 1:2 (With a min slope length of 3m)

Cut Slopes : 1:2



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Drainage

Earth drains and stone pitching are considered where possible erosion and flooding of platforms may

occur. Necessary erosion protection methods were also taken into consideration to minimise erosion of toe lines, inlet and outlet structures and drains along the farm roads.

Concrete drifts were used to prevent the washing away of farm roads at critical points.

Pavement

The pavement design for the farm road network comprises a 200mm wearing course placed on a

compacted in-situ roadbed.

The platform pavement consists of a 300mm wearing course.

Design Assumptions

Centre line testing is not required for the basic farm roads.

Lidar survey information will be used for the detailed design of the roads. The existing levels will be

verified by the successful contractor on site before construction commences.

The following general assumptions were made:

The farm roads will not be upgraded to surfaced roads in the future;

The platform sizes are kept the same as the MeerKAT project;

The maximum dish dimension is 15.5m;

Borehole licensing for additional boreholes will be granted by the Department of Water

Affairs;

Each borehole with a yield of more than 8m3/day will be regarded as a sustainable

construction water source;

Maintenance operations were based on proposed best practice cycles which should provide

the user with an acceptable level of service over 30 years. The SKAO can however downscale

maintenance to an acceptable level of service;

Some maintenance equipment has been procured by the SKA SA. Additional maintenance

vehicles required for SKA1 are described in Section 6.8.3.


Grader blading of the farm roads will be required at least once every two months during the rainy

season and re-graveling of the farm roads will be required once every 5 years. The maintenance of

the drainage will be minimal.

Material Required

There are currently four licensed borrow pits near the core site which have been used to supply gravel material to the existing MeerKAT site.

The existing borrow pits do not have sufficient material to supply SKA1 with material thus additional

borrow pit investigations will be required to source the material required. It is envisaged that at least 11 additional borrow pits (at approximately 22 000 m3 per borrow pit) will be required for the

platforms and farm roads. These will need to be investigated and sourced as part of the site characterisation studies which is outside the scope of the infrastructure and power element design.

There is an existing quarry near Carnarvon which could be made use of for the supply of stone

aggregate. This would however imply the haulage of aggregate over an 80km distance. It is proposed to investigate and source a new stone quarry closer to the proximity of the core site.

All new borrow pits and quarries will require the necessary mineral permits. This will be applied for by SKA SA.



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Drawing Register

Table 11: Drawing Register for Farm Roads

Drawing Number Drawing Title - Description

Roads Typical Drawings

ACC.AP-CP-0001 Typical tear drop shape platform

Roads Layout Drawings

ACC.AP-CP-0002 Farm roads locality plan

ACC.AP-CP-0003 Farm road Sheet 1 of 4

ACC.AP-CP-0004 Farm road Sheet 2 of 4

6.3.3. ACC.AS – All-Weather Landing Strip


A landing strip is currently under construction near the MeerKAT core and is almost completed. It is assumed that the all-weather landing strip will be utilised for SKA1.

Image 12: Airstrip after priming

The position of the landing strip was determined in consultation with the SKA SA, its contracted air charter service and based on the requirements specific to the type of airfield. The landing strip is

located in a position where it does not interfere with construction vehicle traffic. The position of the



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landing strip took the original SKA Site Bid configuration (3 cores) into account with specific regard to obstacle limitation surfaces and approach and take-off paths over antennas.

The landing strip is designed to accommodate a Pilatus PC-12 (design aircraft) and similar. Based on the International Civil Aviation Organization (ICAO) classification, it is a reference code 1B aircraft.

The Pilatus PC-12 is a single engine aircraft seating 8 passengers. Its primary dimensions are:

Wing span : 16,23m

Length : 14,4m

Height : 4,27m

Maximum take-off weight : 4 500kg

The reference field length of this aircraft is 640m. This is the length of runway required for the aircraft to take off at maximum take-off weight (MTOW) at sea level, standard atmospheric conditions, still air

and zero slope.

The length of the runway is 1300m which is surfaced to allow for all-weather operations. A small apron with connecting taxiway is also provided.

The landing strip has been registered with the Civil Aviation Authority (CAA) and the SKA SA has insurance cover. This is acceptable due to the fact that the Maximum Take-off Weight (MTOW) of the

PC-12 is less than 5 700kg which is the weight at which licensing becomes compulsory. This weight restriction has to be respected by all pilots flying into the airfield since any incident at the airfield

involving an aircraft with a MTOW of more than 5700kg will in all likelihood have insurance

repercussions.

For the PC-12 aircraft, the Rescue and Fire fighting category is 3, although with minimal air traffic

movements (less than 700 movements in the busiest consecutive three months) – this could be reduced to category 2. The preferred extinguishing agent for this category is a foam meeting the

minimum performance level B, as described in ICAO Airport Services Manual. As the airfield will not be

licensed, this is an operational and safety issue which is currently the responsibility of the SKA SA.


Geometry

The properties of the landing strip site are:

Position : Threshold North-west (15): 30° 41.163'S ; 21° 27.051'E

Threshold South-east (33): 30° 41.626'S ; 21° 27.664'E

Elevation : 1 048m above mean sea level (MSL)

Reference temperature : 35°C

An apron of 35m x 60m is located at the south-eastern threshold of the runway. This position allows

for the shortest access road to the main road. The apron is of sufficient size to accommodate at least two PC-12 aircraft to be parked simultaneously and to manoeuvre in and out of the parking positions

under own power.

Design Assumptions

No Airfield Ground Lighting (AGL) is required. The landing strip will conform to the requirements for

operations in visual meteorological conditions (VMC).

No fuel storage is required at the airfield. Should this be required in the future for SKA purposes,

provision can be made.



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The following maintenance program is proposed:

Year 7: Year 14:

Fog spray

Repairs over 5% of the runway area (Top layer and Cape seal)

Repaint

Repairs over 5% of the runway area (Top layer)

Re-seal (Cape seal)

Repaint

Year 21: Year 28:

Fog spray

Repairs over 10% of the runway area (Top layer and Cape

seal)

Repaint

Repairs over 10% of the runway area (Top layer)

Re-seal (Cape seal)

Repaint



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6.4. SKA.TEL.INFRA-SA.WAS – Infrastructure Water and Sanitation

6.4.1. WAS.WATER – Upgrades to Water Treatment System

Available Water

There are currently 24 boreholes on the site. All 24 boreholes have been tested for MeerKAT use.

The assumption was made that only the boreholes with a yield of 8m3/day and more would be

regarded as a sustainable source of construction water. The 18 selected boreholes have a maximum

yield of 574.52 kl per day. The chemical tests indicate high fluoride and coliform levels which are a concern.

Due to the high fluoride content of the samples from the boreholes in the area, reverse osmosis systems have been installed for drinking water at the construction camps and at the Site Complex.

Due to the high coliform content of the samples from the boreholes in the area, all water at the

construction camps is chlorinated by means of an in-line chlorinator.

Water Requirements

The water requirement will vary on a daily basis depending on what activities are taking place on site. The different phases of construction will also require different amounts of water i.e. the construction

of roads will require less water than the construction of the concrete antenna foundations. It is recommended to programme the works in such a way that the roads and foundations are not

constructed simultaneously to reduce daily water demand. A high level daily peak estimate has been

made based on calculations done for the MeerKAT project. This is indicated in Table 12.

Table 12: Daily Water Demand

Location/Activity

Daily

Demand

(kℓ)

Daily

Peak

(kℓ)

Comment

Site Complex 7 7 5000ℓ for air conditioning plus 1800ℓ for site complex

Meys Dam Camp 12 12 Allow for 50% more that MeerKAT demand

Losberg Camp 30 30 Allow for 50% more that MeerKAT demand

Road Construction 120 Assume maximum production of 1000m³ per day, 10% moisture per m3

plus 20% losses and contingency

Concrete Works 485 485 Assume maximum production of 800m³ per day, 550ℓ per m³ plus 10%

losses

Construction Dust Control 100 100 Based on 20km haul route per day

Road Maintenance 120 Allow for 100% more that MeerKAT demand

TOTAL 634

The current maximum delivery of boreholes is estimated at 570kl/day. The minimum daily demand is roughly estimated at 630kl/day. There is thus a shortfall of water supply. Water supply is further

dependent on the rain season and can vary from year to year. Additional boreholes will be required to

ensure sufficient water supply.



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Functional Description of Element (Water at Construction Camps)

There are currently two existing construction camps at Meys Dam and Losberg. As per the SKA1

Baseline Design, both construction camps will be utilised for SKA1.

Water supply is provided from a borehole, pumped to a storage tank and boosted by an in-line

booster pump to supply points at both camps. Drinking water is treated before use to conform to

standards for continued potable use. Water used for washing/bathing purposes is chlorinated to reduce the risk of bacteria in the water due to the uncertainty of water quality. The water supply

system will be upgraded for SKA1 by means of additional boreholes, storage tanks and additional reverse osmosis capacity.

Meys Dam and Losberg Water Supply

The water for the Meys Dam site is supplied from two boreholes in the vicinity of the site. Additional boreholes will be provided for SKA1 which will be metered. The existing design capacity for this camp

is 80 persons. The total average annual daily demand (AADD) is 8 000 ℓ/day. Two storage tanks with a capacity of 10 000 ℓ each are provided with additional capacity planned for SKA1.

The standard water demand per person per day for drinking and cooking purposes is 20 ℓ/person/day. With allowance for 80 persons on the site a total of 1 600 ℓ/day is required to be treated by the

reverse osmosis system installed on site. The reverse osmosis system serves as a watering point for

the site with regards to potable water. Additional reverse osmosis capacity is however planned for SKA1.

The water for the Losberg site is supplied from a borehole in the vicinity of the site. This is however

not considered sufficient thus additional boreholes will be provided for SKA1 which will be metered.

The existing design capacity of this Construction Camp is 150 persons. Considering a water demand

of 100ℓ/person/day and an emergency storage for 48 hours, a total demand of 15 000 ℓ/day for

domestic use is obtained. A washing bay for concrete trucks requires about 300 ℓ/truck/day which

equates to 5 000 ℓ/day for the washing of the concrete trucks (a total of about 15 trucks.) Total

storage is therefore for 35 000 ℓ/day. The total average annual daily demand (AADD) is 20 000 ℓ/day.

Provision is made for three storage tanks of 10 000 ℓ each and one tank of 5 000 ℓ. Additional

capacity is planned for SKA1.

With allowance for 150 persons on the site a total of 3 000 ℓ/day is required to be treated by the

reverse osmosis system installed on site.

Bacterial tests done on the water indicate high coliform counts, therefore borehole water is

chlorinated with an in-line chlorinator to reduce the possible effects of bacteria in the water.

For both sites a booster pump and pressure vessel (bladder tank) is incorporated after the storage tanks in order to provide sufficient pressure to the site. The booster pump unit is situated in the

chlorination building. As per the Department of Water Affairs requirements, water meters are installed at each borehole to measure the daily total usage of all boreholes on site. This will be monitored by

the Department to ensure that the daily water usage as approved in the Water Use License for the

site will not be exceeded.

Design Assumptions

Meys Dam

The boreholes must sustain at least 8 kℓ/day for the time span of the camp. Additional capacity will be

provided for SKA1.

Losberg

The boreholes must sustain at least 20 kℓ/day for the time span of the camp. Additional capacity will

be provided for SKA1.



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The following maintenance requirements are envisaged:

Boreholes

Periodic maintenance should take place at boreholes with regard to operation, cleaning of

screens, water level of the borehole, general observations, electrical components etc. Proper

maintenance and checking should prevent unnecessary standing time or dis-functionality due

to components malfunctioning.

Reverse osmosis plant

Replace filters on an annual basis.

Chlorination plant

Daily checking of liquid chlorine mix quantity.

Daily checking of electrical components functionality and general observations with regard to

all components.


Reference can be made to Reference Document [RD 2] – INFRA SA Risk Register which defines the technical risks and proposed mitigation measures.


Reference can be made to Reference Document [RD 1] – INFRA SA Cost Breakdown Structure for the detailed capital, operational and maintenance costs for this sub-element.

Functional Description of element (Water Treatment Plant at the Site Complex)

Water supply at the Losberg Site Complex is provided from two boreholes, pumped to a storage tank

and boosted by an in-line booster pump, chlorinated by in-line chlorination and then distributed to

supply points and to the reverse osmosis system. Drinking water is treated by reverse osmosis before use to conform to standards for continued potable use. Water used for washing/bathing purposes is

also chlorinated.


Water supply at the Site Complex is provided from two boreholes, pumped to a storage tank and

boosted by an in-line booster pump to supply points. Water used for washing/bathing purposes is chlorinated to reduce the possible effects of bacteria in the water.

Allowance was made for 15 persons. The total average annual daily demand (AADD) is 6 500 ℓ/day.

Two existing storage tanks of 10 kℓ each will serve as storage for the site. Keeping in mind that the

air-conditioning units will not be filled on a daily basis, the two 10 kℓ tanks will be sufficient.

A booster pump and pressure vessel (bladder tank) are incorporated after the storage tanks in order

to provide sufficient pressure to the site.

Water for showers or sanitation purposes is chlorinated. The system supplies water to required positions as determined on site.

The standard water demand per person per day for drinking and cooking purposes is 20 ℓ/person/day. With 15 persons on the site, a total of 300 ℓ/day is required to be treated by a reverse osmosis system

installed on site.



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Design Assumptions

The borehole must supply at least 6.5 kℓ/day or 271 ℓ/h for a 24 hour cycle.


The following maintenance requirements are envisaged (see Table 13):

Table 13: Maintenance requirements

Reverse osmosis plant

Replace filters on an annual basis.

Chlorination plant

Daily checking of liquid chlorine mix quantity.

Daily checking of electrical components functionality and general observations with regard to all

components.


Reference can be made to Reference Document [RD 2] – INFRA SA Risk Register for detailed technical

risks and proposed mitigation measures for this sub-element.


Reference can be made to Reference Document [RD 1] – INFRA SA Cost Breakdown Structure for a

breakdown of the capital, operational and maintenance costs for this sub-element.

6.4.2. WAS.WASTE – Upgrades to Waste Water Systems

Sanitation comprises of a package treatment plant. The package treatment plant capacity will be

increased to allow for additional loading.

Meys Dam and Losberg Construction Camp Sanitation

Considering the maximum water demand for domestic use as calculated above, the assumption can be made that the maximum sewage inflow per day will not exceed the water demand. The maximum

effluent which can be generated on the Meys Dam site is 8 000 ℓ/day and on the Losberg site is

15 000 ℓ/day. It is however envisaged to increase the capacity of the existing package treatment plants for SKA1.

A central main sewer line is positioned on the sites. Connection points are constructed at regular intervals to enable sanitation services to be supplied to park home units. Due to the flat gradients

present, a sewer pump sump is provided before the package treatment plant.

An on-site package treatment plant is installed on the sites. The treated effluent from the package treatment plant is discharged into an evaporation bed, formed by a berm on the downstream side of

the package treatment plant. The SKA SA has waste management licenses for these treatment package plants.



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Image 13: Meys Dam sewer package treatment plant

Image 14: Losberg Construction Camp sewer package treatment plant


The following maintenance requirements are envisaged:

Sewer package treatment plant

The operations and maintenance procedures will vary depending on the make (brand) of treatment

plant provided by the contractor. In general the following are deemed good practice procedures (see

Table 14):

Table 14: Operations and maintenance good practice procedures

Weekly

Replace chlorine tablets in chlorine contactor – AWW 20-25 SPA Tabs Stabilised, containing

Trichloroisocyanuric acid

Monthly

Take samples of incoming and final effluent (from chlorine contact tank) and dispatch to a Laboratory

for analysis and report.

Yearly

Check level of contamination and solidification in pre-digestion and purge if necessary.

Every 30 000 Hours (3.5 Years)

Replace diaphragms in air blowers









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6.5. SKA.TEL.INFRA-SA.BLDS – Infrastructure Buildings

6.5.1. BLDS.SBASE – Klerefontein Support Base (all buildings)

Design description of the new MeerKAT offices, workshops and stores constructed for MeerKAT

As per the SKA1 Baseline Design, an assumption was made that the buildings located at the

Klerefontein Support Base will be utilised for SKA1. A draft CON OPS document is still under

development and the Logistic Support Analysis as defined in Reference Document [RD 3] – INFRA SA Integrated Logistic Support Proposal (ILS) still needs to be developed as part of Stage 1. This will

define the logistical support, resources, spares and equipment that will be required for SKA1 which might have an impact on the decision to utilise the existing facilities at the Klerefontein Support Base.

It might become evident during Stage 1 that there are insufficient support facilities at Klerefontein

(e.g. office space for support staff) and provision for additional facilities might have to be reconsidered.

The Klerefontein Support Base workshops and offices are located north-east of the existing Klerefontein Farm house.

Entry to the buildings could either be from the west (parking area) or the south (delivery yard). The storage area (200m²) is located to the east of the “building complex” with access (roller shutter

doors) to the south and west. The workshops are to the north of the building complex with access

from the south.

The design of this facility aims to utilize passive cooling as much as possible, firstly, in the storage and

workshop areas (with a higher volume) by means of a ventilated roof and secondly, by using thermal mass on the western façade (dry pack stone walls) to prevent the harsh western sun from heating the

building during the day. The introduction of a courtyard also aids the cooling of the building, together

with narrow floor plates and adequate cross-ventilation. The office has a double-roof system, which aids the passive cooling of the human interface areas to a great extent.

Key Components

A clean room of 20m2 has been included inside the electronic workshop that complies to US FED STD

209E Class 100 000 clean room (ISO 14644-1 standard ISO 8 Equivalent).

Image 15: Klerefontein Workshops, office and stores constructed for MeerKAT



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Image 16: Klerefontein Workshops, office and stores

Figure 5: Klerefontein support base workshop plan

6.5.2. BLDS.SPLEX - Site Complex (Site, Dish Shed, Pedestal Shed, Accommodation, Security, KAT-7 Shed, Diesel)

Dish Assembly Shed Extension – design description

In terms of the SKA1 Baseline Design, an assumption was made that the existing Dish Assembly Shed

will be utilised for SKA1.

The footprint of the Dish Assembly Shed Extension is designed with the indicative sizes of the dish

moulds and specific dish manufacturing process taken into consideration for KAT-7 and MerrKAT.



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Specific door clearance widths and crane heights were required for the manufacturing of the KAT-7 and MeerKAT Antenna Positioners. The existing structure has been altered slightly to meet these

requirements.

Different equipment / material stores are included in the building and each store has its own roller

shutter door.

The Dish Assembly Shed is fitted with two 10 ton overhead gantry cranes with a hook height of 8.1m.

In order to maximise space within the Dish Assembly Shed, both sets of access doors are configured

in order to allow maximum entrance in to the shed.

In order to minimise RFI emissions from the sheds, specific policies have been implemented for the

electrical wiring, lights and network connections. Earthing, bonding and lightning protection is

provided to protect the building against lightning strikes.

General purpose socket outlets are provided for daily operations.

Refer to Annexure A for the Losberg Site Complex Layout and the Dish Assembly Shed Plan

Pedestal Integration Shed – design description

In terms of the SKA1 Baseline Design, an assumption was made that the Pedestal Integration Shed will be utilised for SKA1.

The Pedestal Integration Shed is located opposite (to the north of) the Dish Assembly Shed, with a

loading / marshalling yard between the two buildings. The footprint is sufficient for the manufacturing of the pedestal component of the MeerKAT Antenna Positioners as well as the lifting and tilting

thereof.

The Pedestal Integration Shed is fitted with a 10 ton overhead crane with a maximum hook height of

12m.

A lean to office has been provided at the rear of the building.

The Pedestal Integration Shed is fitted with the same door configuration as that of the Dish Assembly

Shed extension, thus maximising the entrance and exit space.

In order to minimise RFI emissions from the sheds specific policies have been implemented for the

electrical wiring, lights and network connections. Earthing, bonding and lightning protection is

provided to protect the building against lightning strikes

General purpose socket outlets are provided for daily operations.

Refer to Annexure A for the Pedestal Integration Building Plan.

Image 17: The Losberg Site Complex with Dish Assembly Shed and Pedestal Integration Shed on the left



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6.5.3. BLDS.KAPB - Upgrade to Karoo Array Processor Building

Overview of description

As indicated earlier in this report, the INFRA SA Consortium has deviated from the SKA1 Baseline

Design by assuming that the data processing will take place on site as opposed to Cape Town.

Reference can be made to Section 6.2 (SKA.TEL.INFRA-SA.POWER – which describes the two options

considered for the KAPB in terms of power) and is summarised as follows:

Option 1 (SKA Baseline Design): Utilisation of the existing Karoo Array Processor Building

and the provision of a new SKA1 Container Shed housing RFI-shielded containers to

accommodate additional processor racks.

The existing Karoo Array Processor Building was designed to accommodate 135 processor

racks. A total of 316 processor racks are required for MeerKAT and SKA1 in terms of the SKA1 Baseline Design.

In order to cater for additional racks required for SKA1 while minimising capital cost, it has been recommended that the additional racks be housed in RFI-shielded containers for SKA1

as an interim solution until the Science Data Processor Centre is constructed for SKA2. The

RFI-shielded containers will be housed in a Container Shed (described in Section 6.5.4).

This will entail housing an additional 184 racks in the RFI-shielded containers. Each unit will

be provided with its own HVAC system.

Should the proposed container option not be considered feasible by the SKAO, the alternative

option will be to construct a new building at the proposed “Astronomy Complex” where the

132kV/33KV substation will be constructed (should this be required) which is required in terms of the SKA1 Baseline Design. This option has however not been costed in response to

the RfP.

Option 2 (Optimised option): Utilisation of the existing Karoo Array Processor Building.

The existing Karoo Array Processor building was designed to accommodate 135 processor racks, whereas the proposed updated SKA1 requirement (as part of the SKA SA modelling and

optimisation studies that were undertaken) was identified to be 106 racks in total.

This implies that all the racks for SKA1 can be accommodated in the existing building.

A description of both options is described below.

Option 1 and Option 2

The Karoo Array Processor Building (KAPB) is located on the Losberg Site Complex North-East from

the Dish Assembly Shed. Its position respects the geometry of the existing buildings on the site and is determined by the two main access areas within the building, the delivery area on the west of the

building and the public entrance on the south. The public entrance aligns with a natural central visual

axis that originates at the top of the Losberg Hill.

The building is a buried bunker constructed from concrete retaining walls with soil abutting the walls.

This type of construction has been used for various reasons including thermal performance of the building (keeping external temperature fluctuations to a minimum), RFI shielding advantages (the fact

that the building is buried contributes to the overall RFI shielding) and acknowledging the natural

Karoo landscape.

The building footprint of KAPB consists of four areas:

RFI-screened Data Rack Room

This area houses all the data processor racks and the Maser room. It has a raised access floor area designed to carry the weight of the racks and prevent static interference. This floor was

raised 850mm from the structural floor level, to allow for all services in the void. The Data Rack Room allows for 135 racks.



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Some services run below the floor (power and cooling air) and some services above in racks, i.e. trays for fibre cables, lights, fire detection and fire suppression

Drop-in central passage which links to the Power facility.

The western end of the passage is completely open to allow the dropping-in of equipment with mobile cranes. A 1 ton Jib crane has been provided to assist with the lifting and

unloading of smaller equipment.

Service area

Located east of the RFI-screened Data Rack Room and north of the central drop-in passage, this area contains the HVAC plant and is also the area where the cables, fibres, pipes and air

penetrate the RFI-shielded room. Its structural floor level is 680mm lower than the surrounding areas in order for services to penetrate the Data Rack Room in the void of the

access floor.

KAPB ancillaries area

It includes a laboratory, control room, ablution facilities, store room, an Optic Fibre

Distribution Room and an open courtyard.

The Self weight of the RFI Shielding was taken into account during the design. The structural steel inside the walls and roof of the building are galvanically bonded to the earthing system

in order to provide additional RFI screening.

Electrical and Electronic Engineering

General Electrical Installation

The LV supply inside the building is fed from the Rotary UPS. Attention was given to the design of the cable routes, earthing and bonding in the building which has been designed to minimise RFI

emissions.

A dual redundant power distribution system is used to supply power to the Karoo Array Processor

(KAP) racks. An A and B reticulation system is installed, consisting of dual distribution boards feeding

the racks.

Air conditioning units in the Data Rack Room are also supplied from a dual redundant power

distribution system with manual transfer switches to allow maintenance to the equipment without any disruptions.

All metal cables feeding the Data Rack Room penetrate the RFI shielding through RFI filters.

Fibre cables penetrate the RFI shielding through special waveguide penetrations

Lighting inside the building is by means of LED luminaires, which have been tested to ensure that they

emit minimal RFI.

Extensive earthing, bonding and lightning protection is provided to limit RFI and to protect the

building against direct lightning strikes. The following were provided:

Earth mat and outside ring trench earth conductor with earth rods;

Earth bars in cable trenches;

Earthing of cables entering and exiting the building;

Additional bonding of re-enforcing structural steel in columns, structural walls and floor

screeds;

Lightning down conductors.

Fire detection and gas suppression system

An early warning smoke and heat detection system is installed in all the power areas of the KAPB.

This consists of ceiling mounted heat and smoke detectors as well as an aspirating system in the

processor room, linked to the fire panel.



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A gas extinguishing system is installed in the Data Rack Room and low voltage plant room and consists of gas bottles with distribution piping. The gas extinguishing system is activated by the

smoke detection system.

Access control

Electronic access control is installed at the entrance doors to the KAPB and the entrance to the Data

Rack Room, the optic fibre distribution room and the MV electrical areas.

CCTV cameras are installed to monitor all the network connection areas as well as the MV electrical

control areas.

Mechanical Engineering

Air conditioning and ventilation are provided for the following requirements:

Process

Comfort

Fresh air for the occupants of the building

Data Rack Room – process requirements

The Data Rack Room is an area where all the computing, data management and data transmission equipment is housed. The components are housed in standard 19” racks. Since the components

generate heat, a heat rejection strategy has been developed to maintain all the components at acceptable temperatures. Racks are equipped with heat rejection fans which blow to the back of the

rack. By grouping the racks, a cold aisle and a hot aisle was formed, which provides optimum cooling

for the racks and the components in the racks.

A ceiling void has been provided to optimise the return of hot air to the CRAC units. The chimney

concept can be used for racks with high heat density. The below information provides an indication of the range of cooling concepts for the racks:

The design is based on average of 5kW per rack to 8kW per rack the hot aisle / cold aisle concept is

applicable.

8kw to 20 kW requires special racks with chimneys linking to the ceiling void;

Above 20kW will require special in rack cooling solutions.

As the room is shielded with a radio frequency electromagnetic shield, the penetrations through the shield were kept as small as possible. An air-cooled down-blow computer type air conditioning system

was the most suitable system to be utilised.

Filtered fresh air to overpressure and provide clean air was provided for the Data Rack Room. The

over pressurization minimises the ingress of dust.

For the additional SKA1 racks, modular air conditioning units will be expanded in the KAPB.

For the MeerKAT project six (n+1) modular units are installed. The facility can accommodate eleven

units in total. The total cooling capacity for the eleven units is 640kW.

Fire and Wet Services

Fire Services

The following Fire Protection measures were provided for this building:

One hour fire rated separation for Data Rack Room, A/C Plant Room and Store Room.

Two hour fire-rated separation between the KAPB and Power Building portions of the building

are by means of fire walls and a fire-rated shutter linked to the fire detection system. The

shutter is normally open and only to be closed in case of activation of the fire detection

system and/or power failure to the shutter.

Two separate and remote means of escape from building.

Fire detection and alarm system throughout as described under Electronic Services section.



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Automatic gas extinguishing to Data Rack Room as described under Electronic Services

section.

Portable carbon dioxide and dry chemical powder type fire extinguishers.

Rain and Condensate Drainage Installation

Rainwater entering the areas open to the atmosphere (open courtyard), are drained into floor drains

and channels. These floor drains and channels drain by gravity into an underground collection sump.

Condensate from the air handling units is drained by gravity into the same sump. The sump is fitted with a cast iron cover and frame and will house a duplicate submersible pump set (duty plus standby),

with the necessary lifting chains, isolation valves and non-return valves. Water is pumped from the underground sump into the site storm water drainage system.

The pump operation is automatically controlled by means of an electrical control panel and float

switches. Any fault will activate an alarm condition.

Sanitary Drainage Installation

Soil and waste from the sanitary fittings is drained by gravity into an underground collection sump, situated inside the services shaft.

The sump is fitted with a cast iron cover and frame and will house a duplicate macerator type submersible pump set (duty plus standby), with the necessary lifting chains, isolation valves and non-

return valves. Water is pumped from the underground sump into the site sewer reticulation system.

The pump operation is automatically controlled by means of an electrical control panel and float switches. Any fault will activate an alarm condition.

Radio Frequency Interference (RFI)

The management of RFI is critical for the successful operation of MeerKAT and the SKA and consists

of carefully chosen electrical components, the management of stray currents, operation, screening RFI

generating equipment, etc.

The Karoo Array Processor Building (KAPB) contains a large number of computer systems that

generate high levels of RFI and therefore the following approaches were followed to limit the RFI emissions:

The location behind Losberg assists with the screening and a special RFI berm (Nuweberg) has been

constructed from all the excavated soil.

This assists by not having a direct line of sight (LOS) to any telescope antenna.

The KAPB is mostly below ground level allowing the surrounding soil to absorb RFI emissions;

The Data Rack Room and laboratory is fully screened with electromagnetic shielding

consisting of treated steel panels;

Electromagnetic shielding has been installed as per Table 15:

Table 15: Electromagnetic shielding

Shielding Effectiveness of shield room Frequency: (f) Required value

Electrical field 70 Mhz < = f < 10 Ghz 100 dB min

Microwave field 10 Ghz < = f < 15 Ghz 80 dB min

Extensive earthing and bonding of reinforcing, cables, supports, etc.;

Careful planning of routes for conductive cables. In trenches below the floor level with

attention to earthing and bonding of the trenches

Berms were constructed to limit RFI emissions in the direction of the antennas;

RFI penetrations including RFI filters for metal cables, Waveguide penetrations for fibre

cables, special pipe penetrations and honeycomb filters for air

Double access doors to the Data Rack Room and Lab and Control room area.



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Power Building – description and key components

The Power Building is located on the Losberg Site Complex North-East from the Dish Assembly Shed.

The building is a buried bunker constructed from concrete retaining walls with the soil abutting the walls. This type of construction was proposed for various reasons including thermal performance of

the building (keeping external temperature fluctuations to a minimum), RFI shielding advantages (the

fact that the building is buried contributes to the overall RFI shielding) and respecting the natural Karoo landscape.

Image 18: Karoo array processor building and power building

The building footprint of the Power Building consists of four areas:

Drop-in central passage which links to the KAPB on the west

The western end of this passage is completely open to allow the dropping-in of equipment

with mobile cranes and the use of the 1 ton Jib crane.

Power Building Control Room

Located north of the central passage and east of the service area of the KAPB.

Power Building Equipment

Located north of the central passage and east of the Power Building control area. This is where the Rotary UPS’s, generators and day tanks are located. This area has two ventilation

shafts: Intake and Exhaust shafts.

Power Building Transformer / Switch gear area

Located south of the central passage. Adequate ventilation was provided for in this area.



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Figure 6: KAPB Basement Plan

Electrical Engineering

Reference can be made to Section 6.2.3 SKA.TEL.INFRA-SA.POWER where the electrical design has

been described in detail.

Mechanical Engineering

The transformer room is ventilated to limit the temperature in the room to 40 ⁰C.



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Fire Services

The following Fire Protection measures were provided for this building:

One hour fire rated separation for the Power Control Room.

Two hour fire rated separation between the Power Building and the KAPB portion of the

building by means of fire walls and a fire rated shutter linked to the fire detection system. The

shutter will be normally open and only to be closed in case of activation of the fire detection

system and/or power failure to the shutter.

Single means of escape from the building.

Fire detection and alarm system throughout as described under Electronic Services section for

the KAPB.

Automatic gas extinguishing to the Control Room as described under Electronic Services

section for the KAPB.

Portable carbon dioxide and dry chemical powder type fire extinguishers.

Wet Services

There are no sanitary fittings that require water supply or drainage in the Power Building portion of this building. The underground services trenches were provided with floor drains with backflow stops

to drain any ground water that might enter these trenches. These are drained by gravity to into the

rain and condensate drainage sump.

6.5.4. BLDS.CSHED - SKA1 Container Shed

As described in Section 6.5.3, two options were investigated with regards to housing the additional

data processing racks for SKA1. This section describes Option 1 (as per the SKA1 Baseline Design) - Utilisation of the existing Karoo Array Processor Building and the provision of a new SKA1 Container

Shed housing RFI-shielded containers to accommodate additional racks.

In order to cater for additional racks required for SKA1 while minimising capital costs, it is

recommended that the additional racks be housed in RFI-shielded containers for SKA1 as an interim solution until the Science Data Processor Centre is constructed for SKA2. The RFI-shielded containers

will be housed under a Container Canopy (described in this section below).

This will entail housing an additional 184 racks in the RFI-shielded containers. Each unit will be provided with its own HVAC system. The total number of containers will still need to be confirmed due

to the different suppliers and size of containers available.

Description of work to be done

Two 22.5m x 12m RFI-shielded rooms (to be provided by the telescope element, but will be agreed in

Stage 2) will be housed in a Container Shed for SKA1. Each RFI-shielded room can house up to 96 racks and are made up of five 4.5m x 12m containers. See Figure 7 for proposed layout.



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Figure 7: Proposed container layout

For the SKA1 RFI-shielded containers, a concrete surface bed will be provided. This surface bed will

be constructed on a prepared civil earthworks platform. In order to protect the containers from the natural elements a lightweight steel canopy will be provided over.

To assist with cable routing, a maintenance tunnel has been provided that runs the entire length of

the containers and connects to the KAPB wall on the northern side. Access to the tunnel is via a staircase house. Earth excavated from the tunnel will be stockpiled onto Nuweberg.



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Figure 8: Proposed location of Data Containers to the North West of the KAPB



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Figure 9: Showing plan of cable tunnel and staircase housing



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Figure 10: Showing section through containers, steel canopy, staircase & cable tunnel



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Identification of Technical Risks and Mitigation Measures

Reference can be made to Reference Document [RD 2] –INFRA SA Risk Register where technical risks and proposed mitigation measures are described for this sub-element.


Reference can be made to Reference Document [RD 1] - INFRA SA Cost Breakdown Structure for the breakdown of capital, operational and maintenance costs for this sub-element.

6.5.5. BLDS.CCAMP - Construction Camps (Losberg and Meys Dam) – existing)


There are currently two existing construction camps at Meys Dam and Losberg which will be used for SKA. The provision of power to the camps has been described under Section 0

above and the provision of water and sanitation under Section 0 above. It is envisaged that

only the water and sewerage network at both camps will be upgraded for SKA1 as defined in the Water and Sanitation Section above.

Meys Dam

The SKA SA project will be utilizing the Meys Dam Construction Camp for the following:

Accommodation for contractors (porta cabin-type accommodation to be supplied by

the respective contractors);

The Meys Dam farmhouse has been converted by the SKA SA into office space for

SKA staff and contractors.

The site is levelled and gravelled with a 150mm wearing course.

A 3m high berm, for RFI screening, that will surround the Meys Dam camp site is also

proposed.

Image 19: Meys Dam Construction Camp



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Losberg

The Losberg Construction Camp is utilised for the following:

Accommodation for contractors The Losberg farmhouse has been converted by the

SKA SA into office space for use by contractors.

The site is levelled and gravelled with a 150mm wearing course.

Image 20: Losberg Construction Camp

Environmental considerations

Waste management and other environmental considerations will be handled as part of the EIA process and in accordance with the approved environmental management plan which will

be contractually enforced. The contractor will be responsible for all waste management on

the site. All waste must be disposed at the licensed dump site in Carnarvon. This will be monitored and enforced by the SKA SA Safety, Health and Environmental Officer.


Reference can be made to Reference Document [RD 2] – INFRA SA Risk Register for a

description of the technical risks and proposed mitigation measures for this sub-element.

Capital, operational and maintenance costs

Reference can be made to Reference Document [RD 1] – INFRA SA Cost Breakdown

Structure for a detailed breakdown of the capital, operational and maintenance costs for this sub-element.



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6.5.6. BLDS.HQ – Cape Town HQ Building

As per the SKA1 Baseline Design, an assumption has been made that office space will be

leased in Cape Town for SKA1. There are however two options available to the SKAO which include:

Option 1: Leasing office space in Cape Town

The SKA SA office is located at The Park building in Pinelands, Cape Town. The SKA SA is

presently leasing the 3rd floor (approximately 1500m2) and the 2nd floor (approximately

1500m2). Half of the 2nd floor is leased to the Vincent Palotti Hospital. This sub-lease expires in March 2014. The SKA SA is currently in discussions with Blend Properties to secure the 4th

floor (approximately 1500m2). Should this be possible, it is expected that the SKAO could possibly be accommodated with the SKA SA in this building.

Staff parking will be required at a considerable cost. The need is anticipated to be 15 open and 15 basement parking slots. It is not clear at this stage what the floor space requirement

is for SKA1 and what the timelines are for the occupation in the leased office floor space.

The estimated lease costs per square metre are included in Reference Document [RD 1] – INFRA SA Cost Breakdown Structure. It is however important that should the SKAO be

interested in this option, that this be discussed and pursued with SKA SA as soon as possible.

Option 2: New HQ Building in Cape Town

The SKA SA is currently in discussions with the Western Cape Government to investigate the

possibility of securing government-owned land in Cape Town and constructing a new building for the MeeKAT science, engineering and operations team. Greenfields land has been

identified at the Alexander Hospital in Observatory, Cape Town which is located adjacent to the South African Astronomy Observatory (SAAO). The Western Cape Government has

commenced with the administrative process of securing the land which will require the

signing of a Memorandum of Agreement between the Western Cape Government and the National Research Foundation (NRF). SKA SA is also investigating funding options for the

construction of such a building. The timelines for the construction of this building are dependent on the SKA SA funding model.

There is sufficient land available on the same site to accommodate the SKAO HQ building (SKA2 requirement). Should the SKAO be interested in pursuing this option for SKA2, the

SKAO would have to be party to the same agreement that the SKA SA will enter into with the

Western Cape Government. It is however important that should the SKAO be interested in this option, that this be discussed and pursued with SKA SA as soon as possible.



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6.6. SKA.TEL.INFR-SA.FOUND – Infrastructure Antenna Foundations

6.6.1. FOUND.MID – Foundations for SKA1-MID

The SKA1-mid telescope antennas will be a mixed array of 64 13.5m diameter antennas from the MeerKAT array and 190 new 15m SKA1 antennas. As per the SKA1 Baseline Design, the

SKA1 mid array is proposed to be centred in the same location as the MeerKAT array, and will incorporate the MeerKAT antennas as part of SKA1.

The new SKA1 Antenna Foundations (including assumptions about underlying ground

conditions, foundation types and materials) are discussed below.

Foundation Loads

Loading and performance requirements for the telescope foundations have been defined in the revised SSG loading requirements titled, New Wording for RFI Document on Foundations. Antenna foundations will need to be tailored for the sub-surface geology at each location. It is expected that the foundations can be designed to accommodate variation in ground level

and be built to withstand flooding.

The lists below contain magnitudes of forces and moments on the foundation interface, arising from a 15m diameter offset-fed antenna in operational and survival conditions.

In survival conditions, there must be no permanent displacement of the foundation. In static conditions (gravitational forces only), deflections of the foundation will be subsumed in a

pointing model. The telescope pedestal base is assumed to be a heavy circular flange on a

2.2 m diameter bolt circle.

Static Conditions

Precision Operations

Degraded Operations

Survival (in the “birdbath” position)

Wind 0 m/s 7 m/s 20 m/s 42 m/s

Overturn moment 36 kNm 80 kNm 483 kNm 1056 kNm

Down force 212 kN 220 kN 238 kN 388 kN

Side force 0 kN 8 kN 62 kN 80 kN

Maximum overturning deflection N/A 3 arcsec 36 arcsec N/A

Azimuth torque 0 kNm 5.5 kNm 40 kNm 90 kNm

Following preliminary studies, two possible founding solutions were anticipated, namely:

Pad foundations onto bedrock or competent calcrete, where the depth of this

material occurred at depths of less than 3 m,

Piled foundations (augured piles), where the depth of the competent material

occurred at depths greater than 3 m.

Refer to Annexure B for detailed Antenna foundation load solutions.

The drawing signifying the foundation solutions is attached in Annexure A:

FOUND.MID-SS-0001 – Proposed Antenna Foundation

Comments on the Foundation Loads:

We have assumed that for a pointing accuracy of 3 arc-seconds, only the wind load

should be taken into account. Other loads, e.g. those caused by the antenna own

weight should not have an impact on pointing accuracy.



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We would like to highlight that for the determination of the deflections or rotations in

the design of the foundations, un-factored loads were used, as is the norm in the

design of structural and foundation systems.

Functional description of element

The foundation system for the new SKA1 antennas is described as follows:

a. 190 scattered antenna foundations, each consisting of the following components:

i. 4 x 750 mm diameter piles per foundation;

ii. A 4 200 x 4 200 x 1 200 mm thick reinforced concrete pile cap with a 2 800

mm diameter plinth x 250 mm high;

iii. The design and fabrication of the anchor cage assembly does not form part

of the Infrastructure Package, and will be supplied by the DISH Consortium. This package will however make provision for the casting in of the assembly

cage into the concrete foundation.

iv. 1 x 110 mm diameter Kabelflex sleeve (to be provided by the SaDT Consortium) to house of 2 x 40 mm diameter fibre sleeves, cast into the pile

cap.

v. 1 x 110mm diameter Kabelflex sleeves to house the electrical cables, cast

into the pile cap;

vi. Earthing and lightning protection system;

vii. Provision for an earthworks fill platform around the foundation will be made.

Geotechnical

Refer to Annexure B for the geotechnical investigation details.

Identification of Technical Risks

Reference can be made to Reference Document [RD 2] – INFRA SA Risk Register which describes the technical risks and proposed mitigation measures for this sub-element.



Structure which provides a breakdown of capital costs related to this sub-element.

Additional Notes

It should be noted that some of the antenna positions may be subject to flooding as

they are located in or on the edges of river channels. The true hazard potential at

these sites would need to be reassessed by flood line studies.

Destructive pile tests (trial piles) as well as non-destructive testing of working piles

will be required in order to ensure that the piles meet their performance

requirements. It must be noted that should the Antenna Foundation Loadings

change, this could impact on the foundation design and subsequently the

construction costs. This would have to be managed via change control of the ICD.

Cable entry points have been assumed at this stage.

The length of the piles will be dictated by the soil profiles at each foundation location.

Because these profiles vary quite substantially from location to location, the

estimated costs for the piling may ultimately differ from what was estimated.



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Design Specification and Design Standards (Earthing and Lightning Protection Systems)

Similar design standards are proposed for the SKA1’s lightning protection and earthing system to that of MeerKAT.

Installation and on-site testing is required to ensure a bonded lightning protection/earthing system that conforms to the requirements of SANS 10313, 10292, 10142 , 6100-5-2; 62305

(2011); 10199 (2010).

Earthing

Soil resistivity tests must be undertaken by specialists to ensure that a good representative

value of the current soil resistivity value is obtained.

Based on the tests done for MeerKAT, it is evident that the deeper the piling for the Antenna

Foundation is installed, the better Soil Resistivity (Ω.m) values are obtained.

Design Criteria:

The maximum allowable earth resistance as measured from the dedicated earthing

terminals relative to the earth mass will not exceed the specified 1 Ω value;

Four Symmetrical 70mm² bare copper connections from the earth grid to the anchor

cage will be provided;

The maximum allowable resistance per bonding connection must be 10mΩ;

All earth connections within the earth grid to be Exothermic welded (i.e Cadweld or

Exoweld to minimise both the possibility of galvanic action or electrolysis and

ensuring connectivity and strength of the connection. Note that the exothermic

welding of different material requires special powder compounds;

Two generic earthing layout designs were done based on the 5m and 10m deep

piling method of the antenna foundation structures;

Step and Touch Potentials were evaluated as part of the proposed solution;

Ring main earth connections with deep corner electrodes were incorporated into the

design as part of minimizing the earth potential rise.



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6.7. SKA.TEL.INFRA-SA.COMMS – Infrastructure Communication Systems

No requirements have been identified in the SKA1 Baseline Design for Infrastructure Communication Systems. The INFRA SA Consortium has therefore made assumptions based

on existing knowledge on systems implemented for MeerKAT which will be expanded for

SKA1. This includes the Local Area Network sub-element, Building Management System sub-element and Communication System.

6.7.1. COMMS.LAN – Upgrade to LAN System

This section provides an overview of the LAN services implemented for MeerKAT and proposed upgrades required for SKA1.

Deployment Overview

SKA South Africa has undertaken an initiative to deploy LAN infrastructure, interfaced to the

SKA SA optic fibre backbone, to enable users to access a variety of information services through-out the Karoo Astronomy Reserve (KAR), the SKA SA Cape Town office and the SKA

SA Rosebank office (collectively referred to as the KAR LAN for the purpose of this section).

The KAR LAN is required to provide the following data services:

Scientific data (unidirectional to Cape Town);

Control and Monitoring (CAM) of telescopes;

Webcam data for telescopes;

BMS Access Control;

Voice (IP-telephony);

BMS CCTV;

BMS Data;

Video Conferencing;

Internet Access;

General data: mail, ftp, etc.

Network Authorisation depending on user roles and ID

EduRoam access.

The KAR LAN provides users with end-points at the following locations – the LAN

infrastructure interfaces to the SKA fibre backbone at nodes as indicated:

a. Karoo Astronomy Reserve;

i. Carnarvon POP (LAN interface to the SKA SA optic fibre backbone and to the long-haul fibre infrastructure linking the KAR to Cape Town);

ii. Klerefontein Support Base buildings;

iii. Losberg Site Complex (all buildings);

iv. Construction camps (both interfacing to the SKA SA optic fibre backbone via

fibre splices);

v. Losberg KAT-7 site (containers).

b. SKA Cape Town office;

c. SKA Rosebank office;

d. Remote Users (via VPN).



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A conceptual connectivity diagram of the LAN and its interface with the SKA SA backbone is

shown in Figure 11.

SKA

Pinelands

Klerefontein

LAN Core

SKA LAN

LegendLong-haul fibre

(SANReN/

Broadband Infraco/

Other)TelCo Break-out

Telkom Exchange

Pinelands

VSAT

TerminalCarnarvon

POP

TelCo Break-out

Telkom Exchange

Carnarvon

Workshop

Office

New

Workshop

C-BASS

Houses

ARC

Security

Control

Losberg

Accom./

Office

KAPB

Pedestal

Assembly Shed

Mobile

Homes

Security

Control

Dish Assembly

Shed

KAT7

Core Site

MeerKAT

Core Site

Construction

Camps

ASC/PAPER

containers

VSAT

Terminal

SKA

Rosebank

TelCo Break-out

Telkom Exchange

Rosebank


SKA Fibre

backbone

Future diverse

route

Hutchinson

Kronos

Figure 11: Conceptual SKA SA LAN and associated network

Technical Overview

LAN Infrastructure

The following section provides a brief overview of the nature of equipment provided as part of the LAN infrastructure which will be expanded for SKA1:

Optical Fibre Reticulation – All fibre connections between buildings on the local loop

of the KAR LAN comprise 24-core Single Mode pulled fibre direct-buried in PVC

sleeves;

In-building LAN cabling – CAT7 UTP cabling is utilised in the RFI sensitive Losberg

installations, whereas CAT6 is used elsewhere. All cabling conforms to structured

cabling standards;

Access Network Switches - A combination of 8-, 12-, 24- and 48-port Power-over-

Ethernet (PoE) Cisco Switches are deployed, comprising fibre modules for

connectivity to the fibre backbone (or to other KAR LAN switches as the case may

be). These switches ensure 1Gbps throughput at end-points;

Backbone switches - 10Gbps blade fibre switches in a chassis configuration are

located at the key interfaces to the SKA fibre backbone, namely SKA Cape Town,

Klerefontein Office and Losberg KAPB. A redundant core switch is envisaged for the

KAPB;

Network Racks - Standard 19” racks are deployed throughout, sized in accordance

with equipment volumes. Racks comprise a 500VA UPS (in areas where no site UPS is

provided), PDU (Power Distribution Unit), UTP and fibre patch panels.



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Firewall

Two 1-2Gbps throughput firewalls are located at the Carnarvon POP and the Losberg KAPB. The firewalls include the following security features:

High-performance security services, including application-aware firewall, SSL (Secure

Sockets Layer) and IPsec VPN (Virtual Private Network), IPS (Intrusion Prevention

System) with Global Correlation and guaranteed coverage, anti-virus, anti-spam, anti-

phishing, and web filtering services, and;

Delivers highly effective network-layer and application-layer security user-based

access control.

VLAN Structure

The key data roles, namely Telescope Control and Monitoring, science data, VoIP telephony, basic file handling, video conferencing, CCTV, BMS and Internet access have been segregated

by way of dedicated VLANs designated with the highest priority.

The remaining VLAN’s, designated for contractor Internet access, administration and other, have been allocated lesser priority.

Management traffic for switches runs on a separate VLAN so as not to interfere with normal day-to-day operations.

The VLAN’s are trunked to all end-point switches allowing any VLAN to be used at any location on the network.

Network Access Control

Network authentication is carried out for all users over the entire network. User roles are set up on a network authentication device/server hosted at Cape Town, with a backup replicated

authentication device/server hosted at Klerefontein. The servers cater for the variety of roles such as Science, WWW, CCTV, Administration etc.

The NAC is cross-OS (operating system), ensuring provision for multiple operating systems

such as Linux, Microsoft and Apple on the same network.

The authentication needs to cater for all users, both onsite and remote, for example VPN

users.

The VLAN structure is layered, allowing users to be dynamically assigned to a VLAN based on

their user account/role giving them flexibility of roaming anywhere on the network.

The NAC also adds additional security to ensure that no unauthorised devices/users may

connect to the network. The NAC monitors in real time who is connected to the network and

where they are currently located.

Warranty and Support

All equipment carries a standard 3 year warranty – negotiations are under way for extensions of such warranties.

Maintenance contracts will be negotiated with LAN equipment suppliers.

SKA South Africa has identified the following ICT infrastructure team to support the LAN infrastructure upon full operation of the solution:

4 Cape Town based senior system administrators with one playing a 50% managerial

role and a 50% technical role;

2 Cape Town based junior support staff: one for desktop support and one for general

support



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A rota is envisaged, ensuring permanent presence of at least one of the senior

system administrators on site in the KAR. The junior support staff would move

between Cape Town, KAR and Rosebank as needed.

A stringent capacity building process is to take place during the Defects Notification period of

the LAN deployment contract. Part of this capacity building will be a Cisco certification on the installed equipment.

RFI Approach

Strict adherence to radio frequency interference avoidance requirements has been enforced

to ensure that RF emissions of the installed LAN equipment are kept to satisfactory levels. In

this regard the following key considerations apply for equipment in RFI sensitive areas (Losberg vicinity):

a. Location of equipment

i. All LAN units are located inside screened enclosures wherever possible;

ii. Where a screened enclosure is not readily available the LAN units are located as low down / close to ground as possible. In these instances an isolator

switch mechanism is provided to allow shutdown of LAN equipment;

iii. In other instances special screened cabinets may be considered necessary if RFI levels are beyond limits.

b. LAN Cabling

iv. LAN cabling outside screened enclosures is fibre and not copper wherever

possible. In instances where copper is required outside of screened

enclosures, CAT7 LAN cable with metal connectors is deployed as it offers favourable RFI shielding;

v. Ingress/egress to screened enclosures occurs via RFI ‘feed-through’ filters;

vi. All power cables as well as any copper cables will be run as close to ground

as possible (e.g. inside the trenches in the KAPB) or inside earthed metal

pipes or channelling;

vii. The standard NRS-083-3 is used as basis for installation design.

Before and during the construction phase a rigorous process is adopted to assess the RFI profile of equipment.

RAM (Reliability, Availability, Maintainability) Modelling

The RAM modelling undertaken for MeerKAT indicated an allowance for failures on the overall KAR LAN as approximately 24 hours per annum. This translates to a required total network

availability of 99.73%. These guidelines were utilised in the RAM Modelling performed for the KAR LAN. RAM modelling must be executed for SKA1 as part of Stage 1 as defined in

Reference Document [RD 3] – INFRA SA Integrated Logistic Support (ILS) Proposal to define the SKA1 system requirements.

Interface Control Requirements

The interface requirements between the KAR LAN and key data consumers CAM (Control and Monitoring) and SPT (Science Processing Team) as well as other data consumers has been

defined for MeerKAT.

A similar agreement will be defined for the SKA1 elements such as MGR, CSP, SDP and the

like.



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Other data transfer requirements

Apart from the data flows described above the LAN is required to support the following data interactions:

Business data

Non-telescope CAM

Table 16: Business Network and Non-telescope CAM requirements

Business Data Non-telescope CAM

VoIP-based telephony between the various sites requiring guaranteed QoS

An example of non-telescope CAM data flow is the BMS (building management system), offering centralised control and monitoring of key systems such as power systems, lighting etc. from off-site. CCTV footage from key locations such as equipment containers is also a consumer of LAN bandwidth.

IP-based video conferencing between Rosebank/KAR/Cape Town also requiring guaranteed QoS

File sharing

Access to financial and Administrative systems e.g. online costing, HR, procurement etc.

Internet traffic

Telephony

A Voice-over-IP solution is currently in deployment phase on the KAR LAN. The PABX is to be

hosted at Cape Town and is to be accessible from all end-points on the KAR LAN at Klerefontein, Losberg, Carnarvon and Rosebank via media gateways featuring a distributed

architecture.

The PABX design makes provision for Local Survivable Processors (LSPs) which allow the remote sites’ PABXs to work independently to the mother PABX server in Cape Town in the

event of WAN outage. These LSPs are deployed at the three breakout points, namely Cape Town, Carnarvon and Rosebank as indicated in Figure X.

The PABX installation makes provision for a range of wired (CAT6/7) and wireless (DECT)

handsets.

Provision is made for a Telephone Management System (TMS) for billing and reporting

purposes.

Voicemail mailboxes are provided and can be used by designated users (main site or remote

locations).

Expansion of MeerKAT LAN to address SKA1 requirements

A budgetary provision has been made in Reference Document RD 1 – INFRA SA Cost

Breakdown Structure for the following perceived MeerKAT LAN expansion to SKA1.

Proposed SKA1 Container Shed as per Option 1 (SKA1 Baseline Design) described

in Section 6.5.3.

It is envisaged that the LAN will be extended to the proposed two large container-based rooms to be housed adjacent to the KAPB by way of the installation of network switches and

associated equipment in each room. These switches would be fibre-linked back to the LAN chassis switch in the KAPB. It is envisaged that this LAN connectivity will primarily facilitate

the following traffic:

BMS traffic – the LAN switch will interface with the proposed BMS switch in each

container;



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IP telephony;

And other traffic as identified.

Expansion of the IP telephony platform

It is envisaged that relatively minor expansions to the MeerKAT telephony platform may be

carried out by way of, for example, provision of additional handsets and associated port equipment.

General expansion of LAN capacity

Although the existing LAN design has adequate provision for future expansion in terms of fibre and copper port capacity, additional expansion may be identified in the future.

Technical Risks and Mitigation measures

Reference can be made to Reference Document [RD 2] – INFRA SA Risk Register which

describes the technical risks and proposed mitigation measures for this sub-element.



Structure which provides the capital, operational and maintenance costs for this sub-element.

6.7.2. COMMS.BMS – Upgrade to Building Management System

No requirements have been defined in the SKA1 Baseline Design, however it is envisaged

that the MeerKAT building management system will be expanded for SKA1.

The MeerKAT project consists of a Building management System (BMS), Schneider Citect,

which monitors the key performance factors of the infrastructure. The BMS has a control

room at the Klerefontein complex which are operated by facility management personnel. The BMS is an Ethernet based system where the BMS points of each building is connected to the

Intranet. This allows easy expansion with control and monitoring at any point on the Intranet.

The BMS typically monitors the following parameters:

Grid power supply;

Rotary UPS power;

Data centre cooling systems;

Electrical power quality;

Fire systems;

Access control;

Lights;

Water systems;

Emergency power supplies;

Antenna power distribution.

The BMS interfaces with the ILS (maintenance management system) and the telescope CAM. This is illustrated in the following diagram:



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MeerKAT

BMS

System

Electrical

Systems

HVAC

System

Fire

Alarms &

Suppresion

Access

Control

Water

Systems

Lights

Maintenance

Man System

Telescope

CAM

BMS

Operators

MeerKAT

LAN

RFI

Environment

BMS

Software

Programers

Figure 12: BMS interfaces with the ILS and the telescope CAM

The BMS will be expanded to cater for the new requirements by adding more monitoring points and linking them to the Intranet. The new monitoring points will mostly be located in

the extended processor rooms and will consist of:

Temperature

Humidity

Status of entrance doors

Access control

Fire detection

Gas fire extinguishing system

Electrical power quality meters

Cooling system parameters

The BMS displays and database will be upgraded to correctly reflect and record the

parameters of the new BMS points.

6.7.3. COMMS.RADIO – Upgrade to Emergency Communication Radio System

Purpose of the System

There is no mobile (cell) phone reception at the site and along the roads to the site. This is part of the overall RFI management policy as mobile phones operating at 900 / 1800 or 2100

MHz will interfere with the operation of the radio telescopes on site.

However as part of safe operations, maintenance and construction of the various radio telescopes and related infrastructure, a means of communications is required for:

Emergency communications on site and along the road for SKA-SA staff as well as

contractors;

Operations and Maintenance activities by SKA SA staff;

Construction activities by contractors;

Security by the security service provider.



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In order to provide a mobile and fixed solution, a 66-88MHz analogue radio system has been

deployed on the site. The system selection and geographical layout was done taking into account the requirement not to interfere with the radio telescopes including:

The frequency selection to be well outside the telescope measurement frequency

bands;

The power levels (to avoid out of band saturation);

The location of repeater stations.

For contractors, the handheld and mobile radios are issued on a temporary basis (a deposit is

charged) and at the end of the construction activity the radios are returned to SKA SA.

Description of Current Radio System:

The radio system consists of the following elements:

Handheld radio transceivers;

Vehicle mounted (mobile) transceivers;

Base station transceivers;

Repeater stations on high sites.

Image 21: A typical hand held radio transceiver

Image 22: A typical mobile radio transceiver

Image 23 shows a typical base station transceiver at a security office (The transceiver is the

same as mobile transceiver):

Image 23: Radio Base Station at security office



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Image 24 shows the repeater antennas located on the SENTECH mast at the Wildeperdeberg

high site (about 100km from the core site):

Image 24: Radio Repeater antennas at the SENTECH High Site (100km from core site)

Description of the current radio system network

The SKA SA mobile radio network operates on 4 frequency pairs, plus 2 simplex frequencies,

and 6 CTCSS frequencies:

Table 17: Frequency allocations of the current radio system

Channel Location User Description Tx Freq (MHz) Rx Freq (MHz)

1 Wildeperdeberg SKA SA 70.3000 75.5000

2 Wildeperdeberg SKA Contractors 70.3625 75.5625

3 Meys Dam SKA SA 75.6375 70.4375

4 Meys Dam SKA Contractors 76.0000 70.8000

5 Simplex Chan SKA SA 72.7000 72.7000

6 Simplex Chan SKA Contractors 72.7125 72.7125



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Figure 13 provides an overview of the radio network links between the base stations and the

repeater stations:

Figure 13: Radio network showing links between Base Stations and Repeater stations

Additional requirements for SKA1

For SKA1, the intention is to re-use the current radio system with the following additions:

Re-issue the handheld and mobile radios to contractors;

Possible allocation of additional channels (additional frequency tone panels);

Depending on the coverage at the spiral positions, some additional repeater stations

might be required. This will be confirmed during Stage 1.

Wildeperdeberg

Repeater

MeysDam

Repeater

Losberg Office

Klerefontein

Security

Klerefontein

Site Manager

Klerefontein

Support Base

Losberg

Security

SKA Emergency Radio Network Rev 1

70.4375 75,6375

TX RXEMCOM 8155

75.5000 70.3000

72.7000 72.7000

CH1&4

8&1032

5&7

72.7125 72.7125

70.8000 76.00009&1175.5625 70.3625

75.6375 70.437576.0000 70.8000

TX RXEMCOM TB7100

CH

9&115&7

Repeater

75.5000 70.300075.5625 70.3625

TX RXEMCOM TB7100

Link to Wildeperdeberg

CH

8&101&4

70.3000 75.500070.3625 75.5625

TX RXEMCOM T800

Repeater

CH

8&101&4

70.4375 75.6375

TX RXEMCOM 8155

75.5000 70.3000

72.7000 72.7000072.7125 72.7125

70.8000 76.000075.5625 70.3625

CH1&4

8&1032

5&7

9&11

70.4375 75.6375

TX RXEMCOM 8115 Mobile

75.5000 70.3000

72.7000 72.7000072.7125 72.7125

70.8000 76.000075.5625 70.3625

CH1&4

8&1032

5&7

9&11

MeysDam

Border

Security

70.4375 75.6375

TX RXEMCOM 8115 Mobile

75.5000 70.3000

72.7000 72.7000072.7125 72.7125

70.8000 76.000075.5625 70.3625

CH1&4

8&1032

5&7

9&11

Losberg

Border

Security

70.4375 75.6375

TX RXEMCOM 8155

75.5000 70.3000

72.7000 72.7000072.7125 72.7125

70.8000 76.000075.5625 70.3625

CH1&4

8&1032

5&7

9&11

70.4375 75.6375

TX RXEMCOM TM8255

75.5000 70.3000

72.7000 72.7000072.7125 72.7125

70.8000 76.000075.5625 70.3625

CH1&4

8&1032

5&7

9&11

70.4375 75.6375

TX RXEMCOM 8155

75.5000 70.3000

72.7000 72.7000072.7125 72.7125

70.8000 76.000075.5625 70.3625

CH1&4

8&1032

5&7

9&11



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Reference can be made to Reference Document [RD 1] – INFRA SA Cost Breakdown Structure which provides the capital, operational and maintenance costs for this sub-element.



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6.8. SKA.TEL.INFRA-SA.VEH – VEHICLES

The SKAO has established a CONOPS Working Group to define the Concept of Operations for

SKA1. Further work is required in Stage 1 on the Concept of Operations and the Logistic Support Analysis must be undertaken as defined in Reference Document [RD 3] – INFRA SA

Integrated Logistic Support (ILS) Proposal to define what the logistic support, resource, spares and stores requirements are for SKA1 which will impact on what vehicles are required

during the construction and operation of SKA1. At this stage, estimates have been made by

the INFRA SA Consortium for costing purposes only.

6.8.1. VEH.BAK – Additional Bakkies

SKA SA currently has 11 bakkies (utility vehicles) which are used on site. An additional 4 bakkies will be procured for MeerKAT.

It is envisaged that an additional 7 bakkies will be required on site for SKA1.

6.8.2. VEH.TRANS – Additional People Transporters

Contractors will make provision for transporting construction crews to the site.

The SKA SA currently has 2 people transporters which transport SKA SA support staff to site. An additional 2 people transporter will be procured during for MeerKAT.

It is envisaged that another 2 people transporters will be required for SKA1.

6.8.3. VEH.MAIN – Maintenance Vehicles

The following maintenance equipment has and will be procured for MeerKAT:

1 Mobile Crane (existing);

1 Cherry Picker (existing);

1 Water Tanker Truck (existing);

1 Grader (existing);

1 Tele-backhoe Loader (existing);

4 Trailers (RFI trailer; RFI trailer; Diesel trailer) (existing);

1 Roller (to be procured);

1 Tipper (to be procured);

2 Skyjacks (to be procured);

4 Trailers (to be procured).

It is envisaged that the following additional maintenance vehicles will be required for SKA1:

4 Skyjacks;

6 Trailers.


Reference can be made to Reference Document [RD 2] – INFRA SA Risk Register which

describes the technical risks and proposed mitigation measures for this sub-element.



Structure which provides the capital, operational and maintenance costs for this sub-element.



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6.9. SKA.TEL.INFRA-SA.SEC – Site Security

6.9.1. SEC.SITE – Security

Background

Security of the facilities, equipment, staff, contractors and neighbouring farmers in the Karoo

is of primary importance to the project.

SKA SA has procured security services for the protection of the SKA Observatory facilities, which includes the pre-cursor facilities, site and staff via an open tender process. It is a

requirement that the security service provider be registered with the Private Security Industry Regulatory Authority (PSIRA) of South Africa.

Security Requirements

SKA Site and Site Complex Security Requirements

Figure 14 shows the Karoo Astronomy Reserve facilities.

The SKA Site makes provision for SKA1 and the SKA2 core site(s), the KAT-7 telescope, the MeerKAT telescope and the PAPER radio telescope. Security services are required to monitor

and control access all the facilities on site and at Klerefontein.

Figure 14: Locality map of the SKA Observatory

Current Security Services

Security at the Klerefontein Support Base

One security guard is stationed at the guardhouse at the Klerefontein Support Base. Security

is provided 24 hours a day for seven days a week; therefore two shifts of 12 hours each per day for seven days a week (including public holidays). The guardhouse is fully equipped with

electricity, ablutions and SKA SA’s emergency communication radios. The security guard

controls access to the Klerefontein SKA SA offices and workshops.



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Security at the SKA Site and Site Complex

Figure 15 shows the security detail at the SKA Site and Site Complex on the farms Losberg and Meys Dam. The turn-off from the provincial road to the SKA Site has been closed off and

access is controlled via security booms. Two guards (one stationed at the northern boom

near the Meys Dam farm, and one stationed at the southern boom near the Losberg farm) control access to the site on a 24 hour basis; therefore two shifts of 12 hours each per day

for seven days a week (including public holidays). Mobile guard huts have been erected at these booms and are equipped with electricity, ablutions and SKA SA’s emergency

communication radios.

The entrance to the Site Complex is also controlled via the guardhouse sited at the Site Complex. The Site Complex entrance grants visitors access to the KAT-7, MeerKAT, PAPER,

SKA1 and SKA2 sites (as well as all the facilities listed in Section 6.5.2), hence it is necessary to strictly monitor and control access. A single security guard is stationed at the guardhouse

on a 24 hour basis (two shifts of 12 hours each per day for seven days a week). The guardhouse is equipped with electricity, ablutions and SKA SA’s emergency communication

radios.

Figure 15: Security details required at the Site Complex, Meys Dam and Losberg

Reports and Reporting Structure

All incidents are reported to the SKA SA Karoo Site Manager and recorded in an Incident Reporting Book. Depending on the nature of the incident, a separate report may be lodged

with the South African Police Service offices based in Carnarvon. On a monthly basis a report consolidating and describing all the incidents is issued to SKA SA and the security service

provider’s head office. The status of the incidents is also discussed and recorded (for

example, the status of prosecuting trespassers).

Relationship with the South African Police

The South African Police Service (SAPS) has offices based in Carnarvon. Due to the strategic importance of the SKA SA facilities, the Carnarvon SAPS conducts regular visits to the site

and facilities to confirm that no incidents have occurred and / or to assist with any security-

related matters. SKA SA and the SAPS have a good working relationship and consequently any security-related matters that necessitate support from SAPS is addressed speedily and

efficiently.



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Security Services for SKA1

The security for SKA1 will remain the same as that which is currently available in the Karoo Astronomy Reserve. The only change will be the addition of two more guards to control

access to the proposed deproclaimed road, as discussed below.

Deproclamation of a Section of the Provincial Road

In 2011, SKA SA applied for a section of the Provincial Road (road P02996) between

Carnarvon and Brandvlei to be deproclaimed from a Provincial Road to a Private Access Road (see Figure 16:). The section that will be deproclaimed will run from the intersection of the

P02996 with the R357 to the T-junction with the road from Van Wyksvlei with the P02996

(see Figure 16) this is the same location where the Astronomy Complex as part of SKA2 will be sited). The closure of this road will limit traffic (which, in turn, will limit Radio Frequency

Interference caused by passing vehicles) and will also increase security. At the time of writing, the approval of this request by the Northern Cape Department of Roads was

imminent.



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Figure 16: Details of Deproclamation of Provincial Road

SKA.TEL.INFRA-SA.SE-SEMP-001


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Once the road has been deproclaimed, boomed-off access control points will be positioned at both ends of the deproclaimed road. The access control points will be similar to the access control points

at Meys Dam and Losberg (see Figure 15). One guard will be stationed in a mobile guard hut at the northern point (the intersection with the R357) on a 24 hour basis (therefore, two shifts of 12 hours

each per day for seven days a week, including public holidays), and one guard will be stationed in a

mobile guard hut at the southern point (the intersection with the Van Wyksvlei road) on a 24 hour basis (i.e. two shifts of 12 hours each per day for seven days a week, including public holidays).

Mobile guard huts at these booms will be equipped with electricity, ablutions, and SKA SA’s emergency communication radios.




Reference can be made to Reference Document [RD 1] – INFRA SA Cost Breakdown Structure which

provides the capital, operational and maintenance costs for this sub-element.



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Annexure A

107102-SSG-ELEC-0010 Transmission Network Diagram

POWER.RETC-EP-0103 Proposed New SKA Phase 1 Dish Positions Sheet 1 of 2

POWER.RETC-EP-0104 Proposed New SKA Phase 1 Dish Positions Sheet 2 of 2

POWER.RETC-EP-0108 Proposed New SKA Phase 1 Dish Positions Sheet 1 of 2Electrical

Reticulation Random Layout

ACC.AP-CP-0001 Typical Teardrop Shape Platform

ACC.AP-CP-0002 Farm Road Locality Plan

ACC.AP-CP-0003 Farm Road Sheet 1of 4

ACC.AP-CP-0004 Farm Road Sheet 2 of 4

FOUND.MID-SS-0001 Proposed Antenna Foundation

The Losberg Site Complex Layout

Dish Assembly Shed Plan

Pedestal Integration Building Plan



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Annexure B

Foundation Loads

As the Foundation Load study developed, it became clear that the Precision Operations load case

above, with the very stringent rotational limit of 3 arc-seconds of rotation under the operational

condition, was the critical load case which ultimately defined the foundation size parameters. Furthermore, pad footings were discarded as they could not be made to work economically for this

load case. Instead, optimisation of pile lengths provided the distinction between perceived ‘pad foundation’ and ‘piled foundation’ solutions for individual antenna positions.

Table 3 provides a summary of the foundation requirements for all the load case considered.

Table 18: Antenna foundation solutions

Depth of competent material Pile Cap Pile Details Pile Length

Depth of competent material >3m 4200x4200 x 1200 4 x 750 Dia 10m

Depth of competent material < 3m 4200x4200 x 1200 4 X 750 Dia 5m

Foundation Geotechnical

Ground investigation information available to date

The culmination of information for the SKA1 project is represented in the geotechnical report for the

Phase 2 geotechnical investigation conducted by Aurecon between October and December 2010

(report 106477-G1-00). The geotechnical investigation was conducted for the MeerKAT Layout including 64 antennas and an additional 7 positions at the then identified ‘SKA Core Site’ (3 core site

bid configuration) and entailed the following:

Instrumented (Jean Lutz) Rotary percussion drilling (44 No. positions) to be able to define

the ground profile (soil and rock) at individual antenna positions;

Continuous surface wave (CSW) testing (44 No. positions) to define small strain stiffness

characteristics of the ground profile at individual antenna positions;

Plate load testing (5 No positions, 10 tests) to investigate the larger strain stiffness

characteristics of materials at expected founding level;

Test pitting (5 No positions, at plate load test positions) to define the upper ground profile

through visual inspection.

Simplified ground profile

The following distinctive soil or rock layers were identified from the site investigations done to date:

An upper, sandy horizon, either aeolian, hillwash or alluvial in origin;

A gravelly, poorly consolidated and un-cemented or poorly cemented horizon, of alluvial

origin;

Similar to that above, a gravelly horizon, generally dense but with layers of loose material;

A well cemented, gravel horizon which is thick and competent, and;

The basal horizon of mudstone.

The above horizons have all been tested during the 2011 geotechnical investigations

(reported in Aurecon report 106477-G1-00). A summary of applicable testing and general

comment on competency from a founding perspective are given below.



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Table 19: Relevant layers and their geotechnical parameters

Layer description Relevant profiles and tests Comment

Low strength gravel /

calcrete horizon.

M025 @ 1.3 m - CSW and plate load.



Significant reduction in strength when

saturated. Not considered a good

founding horizon for this reason.

Gravel and calcrete with

interlayered sand. M052 @1.5 m - CSW and plate load.

Some reduction in strength with

saturation. Concern that sand horizons

could have a dramatic effect if

saturated.

Thick, high strength, solid

calcrete.


M061 @ 2.5 m - CSW and plate load. Competent layer.

Mudstone. M045 @ 2.5 m - CSW and plate load. CSW testing in all cases indicates good

strength material.

Note: M025 to M061 are borehole positions.

It is clear from all the testing that have been carried out that the sandy soils, whether alluvial, hillwash or aeolian in origin, which occur at the top of the profile are low density and highly

compressible in nature. Dramatic improvements occur in general at depths of between 2 and 3 m

below surface. While the addition of water to the upper sandy soils tends to result in a significant loss of stiffness, there is a markedly less dramatic response in the underlying calcareous or gravel

horizons.

Design strategy and assumptions

a. In an effort to come to appropriate founding solutions for individual antenna foundations and meet the very stringent rotational limit of 3 arc-seconds of rotation under the Precision

Operations condition, the following strategy was applied.

b. A likely conservative ground profile was defined. For this purpose conditions in borehole M048 (coinciding with antenna position M048) were considered representative of a

conservative ground profile. In summary, the ground profile is as follows:

i. 0 – 1.8 m: Loose to medium dense sand;

ii. 1.8 – 2.1 m: Dense gravel;

iii. 2.1 – 2.5 m: Medium dense sand;

iv. 2.5 – 2.8 m: Dense gravel;

v. 2.8 m – 2.9 m: Medium dense sand;

vi. 2.9 – 3.3 m: Dense gravel;

vii. 3.3 – 3.5 m: Medium dense sand;

viii. 3.5 – 3.8 m: Dense gravel;

ix. 3.8 – 4.1 m: Medium dense sand;

x. 4.1 – 5.0 m: Dense gravel;

xi. 5.0 – 5.3 m: Medium dense sand;

xii. 5.3 - 5.8 m: Dense gravel;

xiii. 5.8 – 6.3 m: Medium dense sand;

xiv. 6.3 – 6.9 m: Dense gravel;

xv. 6.9 – 7.3 m: Medium dense sand;

xvi. 7.3 – 8.0 m: Dense gravel;



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xvii. 8.0 – 9.0 m: Medium dense sand;

xviii. >9.0 m: Mudstone (the mudstone occurs from 5m, depending on the position).

c. Since the bulk behaviour of the subsoil system is what would drive foundation behaviour, this profile mostly provides information toward the variability of the profile and the depth to

bedrock. In relation to compressibility for design, the CSW testing was weighted significantly

more in relation to estimating likely founding conditions.

d. Two possible founding solutions were anticipated, namely shallow pad foundations onto

bedrock or competent calcrete, or piled foundations. As the study developed pad footings were discarded as they could not be made to work for the load conditions provided. Instead

optimisation of pile lengths provided the distinction between perceived ‘pad foundation’ and

‘piled foundation’ solutions for individual antenna positions.

e. Since the required movements for the operational cases are quite small, the strategy was to

conduct an iterative process by which a small strain stiffness ground profile was assumed. The likely maximum pile force for a specific piled foundation option was estimated and a

single pile finite element analysis was performed using Plaxis 2D (version 2010) to estimate the corresponding ground strain values. By assuming a relationship describing the

degradation of stiffness with depth, the iteration process then converged on a likely degraded

stiffness profile associated with the pile and load assumed. It was assumed that the relationship of stiffness degradation would be as described by Rollins et al. (1998) and is as

follows:

20max 102.1161

1

G

G

, where

G = Shear stiffness

Gmax = Small strain shear stiffness

= Shear strain

This process enabled identifying the likely pile cap size, pile configuration, pile sizes and lengths to be

estimated that would enable the design to meet the movement requirements. This was done through

pile group analyses conducted using the Repute 1.5 pile group analysis software.

The small strain ground profile is the basis of the iteration process. In report 106477-G1-00

`preliminary positions for ‘piled’ and ‘pad’ foundations were identified based on judgement of the compressibility of the ground profile (at the time not knowing the exact loading conditions to be

achieved). Based on this split, a minimum small strain stiffness profile was generated for each case

(piled foundation ground profile and pad foundation profile) by choosing the minimum small strain stiffness values measured during the CSW testing at positions anticipated to be either suitable for pile

or pad foundations. The combined stiffness profiles shown as young’s moduli (Emax), are as follows and are shown from foundation level (1.5 m from ground level) to what is perceived to be the

maximum penetration of the seismic waves into the ground in Figure 2.

When the analyses showed that the pad foundation solution was not viable (due to movements

exceeding the 3 arc-second rotational limitation) the ‘Pad Foundation Profile’ was used to estimate

the piled foundation solution for areas where pads were previously required.



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Figure 17: Small strain stiffness profiles used in the design

The final solution proposed, comprised piled solutions using 750 mm diameter piles installed to 10 m depth or 5 m depth (previous pad foundations) respectively.

Distribution of likely foundation applications

For costing purposes it is necessary to be able to estimate the likely distribution of antenna

foundation systems across the project. During the October 2010 to December 2010 ground

investigations, only the MeerKAT and SKA core site (as defined in the SKA SA Site Bid) was covered. This means that for the spiral arrays extending to a distance of roughly 100 km from the core site,

assumptions need to be made to extend the application of antenna foundation systems.

As part of the SKA SA Site Bid submission the antenna positions within a 180 km radius were

addressed in the report “Geological and Geotechnical desk study of the SKA remote telescopes

located within a 180 km radius from the centre of the array” dated 25 July 2011. Although this study spanned up to a radius of 180km, the findings can be used as an accurate reflection of the conditions

within a 100km radius, which covers the SKA1 area.

The process is described as follows:

Additional information sourced

Apart from report 106477-G1-00, the following information was scrutinised in a desk study:

a. Land type survey staff. 1972 – 2006. Land types of South Africa: Digital map. ARC-Institute

for soil, climate and water, Pretoria;

b. Google™ imagery of the site;

c. The published 1 : 250 000 scale geological series covering the SKA Site Bid Investigation Area;

i. 3022 Britstown;

ii. 3118 Calvinia;

iii. 3120 Williston;

iv. 3122 Victoria West.

0

2

4

6

8

10

12

14

0 2000 4000 6000 8000 10000 12000

De

pth

be

low

Fo

un

din

g Le

vel [

m]

Small Strain Stiffness, Emax [MPa]

Piled Foundation profile(106477-G1-00)

Pad Foundation profile(106477-G1-00)



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Methodology used for assessing antenna foundations in a 180 km radius

The following methodology was used in 2011 to derive the most likely founding conditions to expect

at individual antenna foundation positions within the 180km radius of the core site. Geological maps were used to obtain the stratigraphic unit underlying each antenna position.

1:50 000 topographic maps and Google EarthTM imagery were used to identify the landform

on which each telescope would be located;

The pedalogical soil units as mapped by the ARC-Institute for Soil were identified for each

antenna position. It should be noted that pedalogical mapping only describes the soil profile

to a depth of slightly more than 1 m and as such was frequently not of much use unless

shallow rock was identified.

Using the above features and knowledge of the area, combined with the colour and pattern, or

texture of the satellite imagery, a probable soil profile was arrived at. This was constantly compared with existing information such as that obtained during the earlier field work or from knowledge of the

road cuttings, borrow areas for road construction, etc. Once the most likely soil profile had been

arrived at, the most likely foundation solution was derived for each antenna site.

Summary of antenna founding conditions

The antenna sites analysed in detail were restricted to roughly a 180 km radius from the approximate centre of the array.

The vast majority of the antennas are located near the centre of the array. These largely fall into the same main geotechnical unit encountered during the field investigation carried out in November 2011

and reported on in Report 106477-G1-00. This unit consists of Quaternary and Tertiary deposits of

alluvial or vlei sediments partially cemented with calcrete. The earlier work indicates that approximately 45% of the points falling within the Quaternary and Tertiary deposits would be

founded on pads and not piles. However, it is extremely difficult to identify which telescopes would fall into which category without actually doing field tests at each point. Assuming that the above

relationship holds true for the entire area underlain by Quaternary and Tertiary deposits, the

following numbers of piles and pads can be expected:

Table 20: Summary of piled and pad foundations

Total antennas piled according to desk study 2069 A

Total antennas on pads according to desk study See Note 234 B

Total sites (A+B) 2303

Piled on Tertiary or Quarternary 2032 C

Piled not Tertiary or Quarternary (A-C) 37 D

45% of piled will be pads on T or Q (0,45*C) 914 E

Therefore piles on T or Q are (C-E) 1118 F

Therefore estimated total piles will be (F+D) 1155 G

Total estimated pads will be (E+B) See Note 1148 H

Total sites (H+G) 2303

Note: Pad foundations were discarded as a solution. The significance of ‘pads’ relate to the use of

the stiffer ground profile where pad foundations were previously envisaged. This ground profile

resulted in the possibility to use fewer piles.

From the above, one can conclude that roughly 50% of the antennas within a 180km radius will

require a piled foundation solution and the remaining 50% a pad foundation solution for areas with significantly stiffer ground profile. As discussed earlier, it is safe to assume that the same conclusion

can be reached for antennas located within a 100km radius Note that pad foundations were

subsequently discarded as a solution and replaced with piled foundations with shallower piles.