CLARIFICATIONS SOUGHT BY PROSPECTIVE BIDDERS€¦ · According to the 400kV single line diagram, CVT of transformer bays are single phase. We recommend CVT are equipped for each phase,

2

Mariakani 400/220kV Substation

This clarification forms part of the Request for Proposal and Contract documents, and modifies them as follows:

1. CLARIFICATIONS SOUGHT BY PROSPECTIVE BIDDERS

S.No. Clause/Paragraph/Item No. Clarification/Query Response

1 Vol. 2 of 2;

Part 2: Employer’s requirement;

Section VI: Requirements-Technical Specifications;

Clause: 11.2

Suggestion: We suggest to apply lead-acid type battery instead of Ni-Cd type, and apply high frequency charger instead of the thyristor charger

The differences between the high frequency charger and the thyristor charger are listed below.

High frequency charger has higher regulated current accuracy and regulated voltage accuracy, which conducive to the stability of the battery charging and DC output.

High frequency

charger

Thyristor charger

Regulated voltage accuracy

≤0.5% ≤2%

Regulated current accuracy

≤1% ≤2%

Ripple factor ≤0.5% ≤2%

2. Thyristor charger need to be shut down between maintenance and overhauling. However, if you apply high

KETRACO prefers Ni-Cd batteries and thyristor controlled battery chargers as defined in the Specifications, hence please follow the spec and make your proposals on contract award.

3


frequency charger, the faulted module will exit automatically and the other module will still work normally.

3、High frequency charger has lower noises.

4、High frequency charger has higher efficiency:

high frequency charger＞92%;

thyristor charger＞75%

5、High frequency charger has better self-control and controllability.

Please confirm your acceptance.

2 Vol. 1 of 2;


Section VI: Requirements-Drawings;

Drawing number: PB-KET-2014-D-503

There is no switch between the auto transformer and auxiliary transformer. So the failure of auxiliary transformer will cause the trip of the CB at HV side of auto transformer and enlarge the accident.

So we suggest that a falling type safety fuse should be set between the auto transformer and auxiliary transformer, then, the main transformer will not tripped if there is only some fault with the auxiliary transformer, which will make the grid more stable.

Agreed.

3 Vol. 1 of 2;




PB-KET-2014-L-506

In the 400kV single line diagram, four surge arresters are equipped for the shunt reactors. However, there are no surge arresters arranged near the shunt reactors in the 400kV layout, which is inconsistent with single line diagram.

We considered there is no need to equip additional surge arresters for the four shunt reactors.

Surge arresters are shown in Elevation C-C of drawing no PB-KET-2014-L-508 adjacent to the bushings.

4


4 Vol. 1 of 2;




According to the 400kV single line diagram, three sets of CT (each set comprises three phases) are equipped in diameter 3 and diameter 4. Since the IBT 3 and IBT 4 are not in operation in this project, CT in the middle of the diameter should be shorted. So we recommended the two CTs are out of scope of supply, which is the same with diameter 5 or diameter 6, hence the number of 400kV CT should be 36.

Correct observation, but for now bidders should prepare their bids using the bid drawings availed to them.

Revised drawings shall be made available to the winning bidder on contract award.

5 Vol. 1 of 2;




According to the 400kV single line diagram, CVT of transformer bays are single phase. We recommend CVT are equipped for each phase, which is more reliable for the substation operation and protection So that the number of 400kV CVT should be 20, not 16.

For now please follow the specs, your proposals can be made on Contract award.

6 Vol. 1 of 2;




&

Vol. 1 of 2;

Part 1: Bidding Procedures;

Section IV: Bidding Forms-Price Schedules;

Price Schedule 4

According to the 220kV single line diagram, we consider the number of 220kV CT is 36, not 57.

The total number of CTs include metering CTs.

5


7 Vol. 2 of 2;


Section VI: Requirements-Schedules of Technical Information;

B. 220Kv Open Terminal Switchgear;

Clause: 11.8

Please provide the rated voltage of 220kv surge arrester. As per Bidding Document Volume 2 of 2; Section VI: Technical Specifications; Clause: 7.1; Paragraph 1, Bidders are expected to carry out insulation studies which will produce the required surge arrester characteristics. As a general guide 198kV can be used.

8 Vol. 2 of 2;



Clause: 1.6

Please specify the time interval of the maximum wind velocity of 140km/h referred in Volume 2. For example, it is the fastest average wind speed within 3s, or the fastest average wind speed within 10min, or the fastest average wind speed within any other time interval.

The reference wind speed is 140kmh.

9 Vol. 2 of 2;



Clause: 22.11

Local water connection point is 4km or 2km distance from the substation?

The local water connection point is 16km distance, to be arranged and constructed by the contractor. The water pipeline shall be one in number for supply to the substation and a 1km Tee off for possible future connection to the local area.

10 Vol. 1 of 2;



Drawing number: PB-KET-2014-L-501

Please provide the detail longitude and latitude of the site. Refer to Drawing number: PB-KET-2014-L-501 & Mariakani Substation Spot Heights drawing.

6


&

Mariakani Substation Spot Heights drawing

11 Vol. 1 of 2

Part 2: Employer’s requirement

Section VI: Requirements- Technical Specifications;

Appendix A – Bid Drawings;

Drawing number: Mariakani SS BH9 soil investigation

On the sheets 186 & 189 are indicated the surface and geographical coordinates, also the bore holes made but they aren’t indicated the situation inside of the surface. Please, where are the situations of each bore hole?

On the sheet 188, Soil test Result Summary, Ministry of Roads, this is the characteristics of soil, Borehole number 9 and MARIAKANI SS (MSS) , this one is corresponding to pages number 186 and 187. Is it OK?

On the sheet 189, we have the Cone Penetration Test, section Rabai – Tsavo, but for Mariakani SS, we don’t have any information. Please, could you send the geotechnical typical study where we can see the depth of foundations and the characteristics of soil?.

Equally, if KETRACO has Soil Resistivity Study, could you be delivery it?

The soil data provided was obtained along the Mombasa-Nairobi transmission line; it is therefore an indicative and not actual scenario of the Mariakani site.

All soil aspects shall be at the bidders’ risk and conditional bids on these grounds shall not be accepted.

12 Vol. 2 of 2;



Clause: 22 – Civil Works

Situation in kilometers from Substation Site of material bank.

Material sourcing is entirely the contractor’s responsibility, however the material should comply with Section VI: Requirements-Technical Specifications; Clause: 22.17.

Situation in kilometers from Substation Site of Rubbish tip or dump useless material.

Refer to Section VI: Requirements; Technical Specifications; Clause: 22.17.7.9.

7


Situation in kilometers from substation distribution line for Electrical supply.

Refer to Section VI: Requirements-Technical Specifications; Clause: 22.11.

Localization of road to entrance in the Substation. Refer to Section VI: Requirements-Technical Specifications; Clause: 22.17.15.1.

13 Vol. 2 of 2;



Clause: 9 – Telecommunication Systems

Regarding to the Telecommunication Systems, could you clarify the scope of the supply? If we have to supply the remote terminals, etc.

Telecoms scope of supply is as provided in Bidding Document Volume 2 of 2; Section VI: Technical Specifications; Clause: 9.

14 Vol. 2 of 2;



Clause: 10 – Substation and Control System

Regarding to the SCADA and EMS for (NCC) and (RCC), could you clarify the scope of the supply?

SCS scope of supply is as provided in Bidding Document Volume 2 of 2; Section VI: Technical Specifications; Clause: 10.

15 Vol. 1 of 2;


Section I: Instruction to Bidders;

Clause: 2.4.2

In case of a JV, must all members have bought the bidding documents and send an EOI (expression of interest)? Or it is enough that only one of the members has bought it.

Only one member is sufficient.

8


In case of a JV, if one member meets the specific reference in 2.4.2 but they don’t have experience out of their country, but a wide experience in similar projects even larger, and other member of the JV has a wide international experience in EPC industrial contracts, but not similar to this project, could it be possible to justify the experience out of the country with other large industrial projects? Therefore one member would meet with the experience in similar projects and another one with the management of large contracts internationally.

Experience must be in similar projects. Refer to Section I: Instruction to Bidders; Clause: 2.4.2 and also Section III: Evaluation and Qualification Criteria; Factor 2.4 – Experience.

16 Vol. 2 of 2;



Appendix A - Bid drawings

Drawing number:

SH 1- 2

182AKPDE2006A

ADT-559/AD

The drawings listed against 1, 2 and 3 are not available with the tender documents. Please provide the same.

1) SH 1- 2 - Typical staff permanent accommodation drawings

Refer to pdf copy of Drawing number: SH-1-2-Construction of Isinya 400/220kV Substations- Single Housing Units.

2) 182AKPDE2006A - Existing 220V terminal tower Refer to pdf copy of Drawing number: 182AKPDE2006A - CLEARANCE DIAGRAM FOR TT " 220T90°/T60°/T30°/T10°/DE " 220 KV D/C.

3) ADT-559/AD - 400KV Double Tension hardware fittings for quad ACSR lark conductor

Refer to Drawing number: PB-KET-2012-L-201: 400kV Double Tension H/Ware fittings for Quad ACSR Lark Conductor.

17 Vol. 2 of 2;




Quantity mismatch between SLD/layout and price schedule for Surge Arrestors

As per SLD/Layout - 30nos.

As per Price schedule - 18nos.

Please confirm the quantities as 30 Nos.

12nos surge arresters are accounted for with the shunt reactors, that is, defined as shunt reactors with integral surge arresters in drawing number PB-KET-2014-L-506.

9


Drawing number:

PB-KET-2014-D-503

PB-KET-2014-L-506

&

Vol. 1 of 2;



Price Schedules: Schedule No. 1

Please also confirm the supporting structure quantity in price schdule-1, Item No. 9.6 as 30 Nos.

18 Vol. 2 of 2;




Drawing number:

PB-KET-2014-D-503

PB-KET-2014-L-506

&

Vol. 1 of 2;




Quantity mismatch between SLD/Layout and price schedule for Post Insulator

As per SLD/Layout - 162nos.

As per Price schedule - 120nos.

Please confirm the quantites as 162 Nos.

Please also confirm the supporting structure quantity in price schdule-1, Item No. 9.7 as 162 Nos.

For clarity Schedule number item 1.8 should read ‘Underhung insulator’.

The number of post insulators remains correct at 120nos.

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19 Vol. 2 of 2;


Section VI: Requirements - Technical specification;

Clause: 3.3.8

&

Vol. 1 of 2;




Please confirm / clarify whether the underhung insulators shall be Post Insulator Type or Disc Insulator Type

Insulators shall meet the requirements of Bidding Document Volume 2 of 2; Section VI: Technical Specifications; Clause(s): 3.3.7 and 3.3.8.

20 Vol. 2 of 2;




Drawing number:

PB-KET-2014-D-503

PB-KET-2014-L-506

Please confirm that the 400KV and 220KV Disconnectors are of Center Break Type.

Disconnectors shall comply with Bidding Document Volume 2 of 2; Section VI: Technical Specifications; Clause: 4.3.1 the depictions are only indicative.

21 Vol. 2 of 2;


Section VI: Requirements-Technical

Please provide the rated current of 400KV and 220KV disconnector

Where equipment ratings are not clear please use Busbar ratings.

11


Specifications;


Drawing number:

PB-KET-2014-D-503

PB-KET-2014-D-502

22 Vol. 2 of 2;




Drawing number:

PB-KET-2014-D-502

PB-KET-2014-P-517

PB-KET-2014-P-516

PB-KET-2014-P-515

As per the 220KV Single line diagram, 220KV busbar rating specified as 2000A, but in Typical protection diagrams the CT rating specifed as 2500-1500/1A.

Please confirm / clarify 220kV Busbar rating and CT rating.

Please follow the Busbar and CT ratings as given in the Bid drawings.

23 Vol. 2 of 2;


Section VI: Requirements -Technical specification;

Clause: 22.18.1.2

Please clarify the Illumination levels specified are Average value or Minimum Value

As per Bidding Document Volume 2 of 2, Section VI: Technical Specifications; Clause: 22.18.1.2; Paragraph: 7 the illumination levels are minimum.

24 Vol. 2 of 2;


Please confirm that the illumination scope for the future area is NOT required.

Lighting system design shall comply with Bidding Document Volume 2 of 2; Section VI: Technical

12


Section VI: Requirements - Technical specification;

Clause 22.18.1.2

Specifications; Clause: 22.18.1.2; Paragraph 9.

25 Vol. 1 of 2;




Item 10.49

In price schedule only 2sets of firewalls were listed but for two transformers - one firewall and for four reactors - three firewalls are required, total 4sets required. Please confirm.

Confirmed. Bidding Document Volume 1 of 2; Section IV: Bidding Forms; Price Schedules: Schedule No. 2; Item: 10.49 becomes 4sets and Schedule No 4; Item 10.49 becomes 4sets.

26 Vol. 2 of 2;



Clause: 1.6

Please Specify the wind load on Conductor Refer to this clarification S.No. 8

27 Vol. 2 of 2;



Clause: 1.6

Please confirm whether the Ice Loading details are applicable? If so please clarify the weight of Ice to be considered per meter.

Ice loading is not applicable.

28 Vol. 2 of 2;


Section VI: Requirements-Technical

Please confirm that as per the service conditions of Annual Average Temperature of 30°C, zone 2 ambient temperature shall be considered for Auto Transformer Design criteria

Correct.

13


Specifications;

Clause: 1.6

&

Section VI: Requirements - Schedules of Technical Information;

Item K – 400/220KkV Power Transformers

29 Vol. 2 of 2;



Clause: 1.2

Please confirm whether the same conductor including OPGW and ACS can be re-used

Please follow the Specifications.

30 Vol. 2 of 2;



Clause: 8.2.2.4 & 8.2.2.5

&


Drawing number:

PB-KET-2014-P-509,

PB-KET-2014-P-510,

PB-KET-2014-P-515,

It is not clear, how a Separate 400kV & 220kV Differential protection (87HVC1, 87HVC2) and Separate 220kV & 11kV Differential protection (87HVC1, 87HVC2) can be employed.

Please confirm whether Auto-Transformer protection is by 3-winding differential protection Relay.

Request to provide more clarity

Auto-transformer protection is by 2-winding differential protection relay.

14


PB-KET-2014-P-516

31 Vol. 1 of 2;


Section II: Bid data sheet;

C. Preparation of bids;

ITB 16.2

Please clarify the scope and requirement of 220KV HV cable.

No 220kV cable is required for this project. Please remove Item no. 10 from Bidding Document Volume 1 of 2; Section II: Bid Datasheet; Clause: ITB 16.2.

32 Vol. 2 of 2;





Please provide the soil resisitivity of the substation area Bidders shall carry out their own soil tests after Contract award.

33 Vol. 2 of 2;



Clause: 8.2.2.2

&

Appendix A – Bid Drawings

Protection SLD

Please provide the make and type of protection details for

1) 400kV Isinya 1 & 2 line feeders

2) 400kV Dongo Kundo 1 & 2 Line Feeders

3) 220kV Rabai 1, 2 & 3 Line Feeders

4) 220kV Malindi Line Feeder

5) 220kV Kiambere Line Feeder

Bidders shall take note of the last paragraph of Bidding Document Volume 2 of 2; Section VI: Technical Specifications; Clause: 8.2.1.1.

For Dongo-Kundu, Malindi line, Kiambere line and Rabai 3 line, Bidders are free to propose make and type of their own choice.

220kV Rabai 1 & 2 line, the distance relay (main 2) is SEL 421 and the differential relay (main 1) is Siemens 7SD52.

400kV Isinya 1 & 2 line, is currently under design and the winning bidder will be informed of the make and

15


type of the relays at contract award.

34 Vol. 2 of 2;



Clause: 22.18

Please provide us the detailed Control Room requirement The control building shall house the following in separate rooms:

Relay and metering panels room

Battery room

Battery chargers and LV distribution boards

Communication equipment room

Office

Control and protection room

Control room

Separate washroom for Ladies and Gents, water closet, Urinals and Bath

Equipment store

Kitchen The control room within the control building shall have full view of the switch yard.

35 General Please provide required size of the Guard house The size of the guard house shall be 5m x 2.5m inclusive of water closet. The orientation shall be such that the area of the substation can be viewed from the guard house.

36 Please provide location of Store room and Residential houses

To be finalized on Contract award.

37 Please provide the soil resistivity of the substation area Refer to TAC1 clarification no 32.

38 Please provide us the initial Tension on 400kV & 220kV Phase conductors and shield wire for Structure Design

In line with Bidding Document Volume 2 of 2; Section VI: Technical Specifications; Clause: 23, this is the Bidder’s responsibility.

16


39 Vol. 2 of 2;



Clause: 22.8

Kindly specify whether the substation shall be made in finished level higher than the nearest highway road level. If so, kindly specify the level difference between the substation and the nearest road level.

This is subject to detailed design by the winning bidder.

40 Vol. 2 of 2;





Further to the soil bore hole data provided, kindly specify water table level data of the substation for the design of foundation if any available.

Refer to TAC1 S. No.: 11.

41 Vol. 2 of 2;


Section VI: Requirement - Technical Specification;

Clause: 22.17.15

Kindly specify the requirement and the code of practice to be followed for concrete road inside the substation.

Refer to Section VI: Requirement - Technical Specification; Clause: 22.4 for standard codes and Kenya Road Design Manual; Part III: Materials and Pavement Design for New Roads.

42 Vol. 2 of 2;



Clause: 22.17.12.5

Kindly provide the out fall point for storm water drains. This is subject to detailed design by the winning bidder.

17


43 Vol. 2 of 2;



Clause: 22.5.2

Kindly provide the specification requirement of substation store building whether it is RCC framed structure with flat RCC roof slab or RCC framed structure with steel roof truss. Kindly clarify.

The Bidder shall design the building to the requirements stated in Section VI: Technical Specifications; Clause: 22.5.2 as well as the following:

The storeroom structure will be RCC framed structure with steel roof truss.

It shall have separate rooms for an office, storage room and WC washroom, all air conditioned.

The storage room shall be further partitioned to house protection spare parts and telecomm spare parts separately.

Water, electricity and internal telephone services will be provided by the contractor.

44 Vol. 1 of 2;


Section IV: Bidding forms;

Price Schedules: Schedule No. 2 & 4

The Store building is included in the substation scope of work.

Whereas in the price schedule of civil works it is not available.

Kindly clarify

Correct observation. Please add 14.6 Store building to Bidding Document Volume 1 of 2; Section II: Bid Datasheet; Price Schedules No. 2 and 4.

45 Vol. 2 of 2;



Clause: 22.5.1 & 22.5.2

1) Kindly provide the location of the staff housing units in the substation overall layout PB-KET-2014-L-504 Rev 3.

2)Kindly provide the drawing for the Double Housing Unit as mentioned in the clause 22.5.1

3)Single Housing Unit dimension shall be as per the drawing or it shall be as per the area specified in the claues as 150sqm for each house and 60sqm for additional servant quarter. Kindly confirm.

1) This will be agreed with KETRACO on Contract award.

2) Refer to drawing SDH-2/2 Double housing units in Annex 1.

3) Refer to drawing SDH-1/2 Construction of Isinya 400/220kV Substation – Single housing units

18


46 Vol. 2 of 2;



Clause: 22.18

Kindly provide the specification requirement of substation control room building whether it is RCC framed structure with flat RCC roof slab or RCC framed structure with steel roof truss. Kindly clarify.

Control building shall be RCC framed structure with water proof RCC roof slab and IT5 sheets.

47 Vol. 2 of 2;



Clause: 22.18

&

Vol. 1 of 2;



Price Schedule No. 2

Item: 10.15

Kindly provide the finishing schedule for the substation control room building

Refer to TAC1 clarification number 34.

48 Vol. 2 of 2;



Clause: 22.10

Kindly provide the difference level between the finish floor level (FFL) of the control building and the Finished Ground Level (FGL)of the substation in general.

This is subject to the Bidders designs.

49 Vol. 2 of 2; Kindly provide the specification requirement of substation The final choice of material is the Bidder’s

19




Clause: 3.3.9

&

Vol. 1 of 2;




Item: 9

structural steel (such as grade of structural steel, whether type of the structure used is lattice type / pipe type or builtup sections ) which is used for the gantry structures and equipment supporting structures.

responsibility, most importantly the designs should meet the requirements of Bidding Document Volume 2 of 2; Section VI: Technical Specifications; Clause: 22.4.

50 Vol. 2 of 2;



Clause: 3.1 & 3.3.9

Kindly provide the design factor of safety for normal condition and short circuit force condition for the design of substation steel structures.

Or else specify the standard of practise to be followed for the same.

The Eurocodes shall be used design.

51 Vol. 2 of 2;



Clause: 23.1.3.1

Kindly provide the initial tension on the earth wires and the stringing conductors for the 400/220kV Substation.

Or else specify the standard of practice to be followed for the same.


52 Vol. 2 of 2;


1)The maximum wind velocity is specified for the transmission line as 140km/h as specified in the clause 1.5 , page 19 of 677 of the specification. Whether the same

1) The service conditions are for Mariakani substation site.

20



Clause: 1.6

wind velocity is considered for the substation steel towers and equipment supporting structures.

2)Kindly specify the standard of practice to be followed for wind pressure calculation on the substation towers and steel supporting structures as well as stringing conductors.

2) For wind pressure calculation use IEC 60826: 2003 or any other internationally accepted standard.

53 Vol. 2 of 2;




Drawing number: Mariakani SS Spot Heights

The work involves site preparation & earth works. What is the nature of terrain? Is the site fairly leveled or any extensive cutting of earth and filling from borrowed earth is involved?

If yes, what is the approximate area of the land needing development and what is the extent of cutting and filling? If any contour map of site is available showing the spot levels, pl obtain. What is the approx. distance of the borrow pit from where borrowed earth will be taken for filling, if required?

Bidders were taken to site on 23rd January 2015.

Refer to Mariakani SS Spot Heights drawing.

All matters regarding design and execution of earthworks is the bidders risk and responsibility.

54 Volume 2 of 2;

Section VI: Technical Specifications;

Clause: 1.7 – Transport.

Is a permanent access road to the substation available? Can we get the information about the main approach road to the substation. (Eg, how far from the main highway or nearby motorable road, whether the access road is wide enough and hard enough to take heavy load of 200MVA Trf?

Refer to Bidding Document Volume 2 of 2; Section VI: Technical Specifications; Clause: 1.7 – Transport.

55 Volume 2 of 2;


Clause: 23.6

We understand slope protection is involved. Is the substation to be constructed at an elevated level? What is the elevation with respect to the adjacent road level? What kind of slope protection is envisaged?

This is subject to the bidders design.

Should any slope protection be required, stone pitching shall be used.

56 Volume 2 of 2;


Is construction water and construction power available near the substation area?

Refer to Bidding Document Volume 2 of 2; Section VI: Technical Specifications; Clause: 22.11 and TAC1 S.

21


Clause: 22.11 No.: 9.

57 Vol. 1 of 2





What is the type of soil (Eg. Whether Rocky, normal soil, or hard laterite soil etc) Is the soil resistivity value available?

Refer to TAC1 s. No.: 11 & 32.

58 Is there any data on water table at site available? Refer to TAC1 s. No.: 11 & 40.

59 Is sufficient space available at site for storage of equipment/ mterials prior to installation? (Approx 1000 to 1200sq.P of space will be required for storage etc)

Bidders were taken to site on 23rd January 2015. The substation land is 200 acres.

60 Vol. 1 of 2




Drawing number: PB-KET-2014-L-501

The scope involves Loop-in-Loop-out of existing Isinya-Rabai transmission line in the new substation. What is the approx. distance between the transmission line transition area to substation?

Refer to drawing number PB-KET-2014-L-501

61 Whether space is available for Contractor’s site office near to the site or within the site area? Is there a nearby town for camp site / labour camp? Whether facility for temp accommodation available near to the site?

Only the site offices shall be located within the site. Accommodation/camp site/labour camp for contractor’s employees is the bidders’ responsibility.

22


62 Vol. 1 of 2;



Price Schedule No. 1;

Item: 1.6

For 400kv Surge Arrester, the quantity in price schedule No.1, item 1.6 differs with quantity in SLD Drawing. Please conform and revise if needed.

Quantity of surge arresters in price schedule number 1 is correct.

63 Vol. 1 of 2;



Price Schedule No. 1;

Item: 1.1 & 2.1

For 400kv and 220kv Circuit Breaker, it is required single

pole operation in technical schedules item A2.3、B2.3, but

in price schedule No.1, item 1.1、2.1 it is three pole operation. Please conform which to be used.

The wording in price schedule No 1 was to make it clear that circuit breaker quantities are supposed to be for three poles, hence, please follow the technical schedules

64 Vol. 2 of 2;



Clause: 8.2.2.2

&


Protection SLD

Please confirm the type of line protection relay connecting

220kv MALINDI、RABAI、KIABERE.

Refer to TAC1 S. No.: 33

65 Volume 2 of 2;


Clause: 8

Please conform the debugging of 220kv

MALINDI、RABAI、KIABERE line protection is in contractor’s work scope or not ?

Follow the Protection specifications as provided in Bidding Document Volume 2 of 2; Section VI: Technical Specifications; Clause: 8.

23


66 Volume 2 of 2;


Clause: 10

The contractor’s modification of existing NCC RCC communication & control system need cooperation of ABB Switzerland. Please conform employer will coordinate with ABB Switzerland.

The SCS scope of work is as given in Bidding Document Volume 2 of 2; Section VI: Technical Specifications; Clause: 10

67 Vol. 2 of 2;





The soil survey report shows there many rocks in 0-10m depth, please conform.

Refer to TAC1 Clarification No 11

68 Please provide soil resistivity. Refer to TAC1 Clarification No 32

69 Vol. 1 of 2;


Section II: Bid data sheet;

Clause: ITB 19.1

In ITB 19.1, contractor shall furnish a Bid security and counter guaranteed by a recognized Kenya bank. Can the foreign contractor directory furnish a bid security from a recognized Kenya bank?

Yes.

70 Where is location of staff housing units in the plan? Refer to TAC1 S. No.: 36.

71 Vol. 1 of 2;

Section VIII: Particular Conditions;

Clause: GC5.2.10

For Section VIII Particular Conditions GC5.2.10, CLARIFICATION: How long is the period of the extended defect liability? 2 years or 5 years?

5 years.

72 Vol. 1 of 2; For Section II Bid Data Sheet ITB 11,1(h), “d)” and “In general” have incoformity, CLARIFICATION: how long at

Refer to Section II Bid Data Sheet ITB 11,1(h), “d)”

Equipment similar in all specifications to those offered

24


Section II: Bid Data Sheet

Clause: ITB 11.1(h), “d)”

least should the major similar equipment be in service? 2 years or 5years?

as the major equipment to be supplied must have been installed and been in service for at least five (5) years outside the country of manufacture. The bidder shall submit documentary evidence.

73 Vol. 1 of 2;

Part 3: Conditions of Contract and Contract Forms;

Section VII: General Conditions;

Clause: 1.1

We didn’t found the definition of the engineer or consultant in the bidding documents; however, we found there are many descriptions about the engineer or consultant. Please clarify that if there is engineer or consultant during the evaluation and execution of the said Project?

Engineer/ Consultant means the person appointed by the Employer to act as the Engineer for the purposes of the Contract or other person from time to time appointed by the Employer and notified to the Contractor as replacement to the Engineer.

74 Vol. 1 of 2;



Section IX: Contract Forms;

Performance Security Form – Bank Guarantee

There is no such kind of description indicate that the performance security will reduced by half in the GC and SC, please kindly confirm that the guarantee will be reduced by half after the Operational Acceptance according to the form of Performance Security.

Confirmed.

75 Vol. 1 of 2;



Clause: 2.1.3

Please kindly confirm that the price of Schedule No.6 will not including in the Bidding evaluation Price.

Confirmed.

76 Vol. 1 of 2;

Part 3: Conditions of Contract and

Please confirm the payment will make though L/C i.e. documentary credit or direct transfer?

No. Payment shall be through direct transfer.

25


Contract Forms;


Article 3.1(d)

&

Appendix 1: Terms and Procedures of Payment – Payment Procedures

77 Is there any data on water table at site available? Refer to TAC1 s. No.: 11 & 40.

78 Vol. 1 of 2;



Clause: 5.2.10; 5.2.2 & Note of SC 5.2.10

These descriptions are self-contradictory. Please confirm the extended defect liability period for critical components covered under the extended defect liability are 400/220kV Autotransformer, 400kV shunt reactors, circuit breakers and substation control system and the period shall be two (2) years from the date of Operational Acceptance.

Refer to S. No.: 71.

79 Vol. 1 of 2;


Section II: Bid Data Sheet;

Clause: ITB 16.2

As we know, the usage of the Manufacturer’s Authorization is confirming the manufacturer of the essential/high-tech equipment shall cooperate with Tenderer in the Contract execution period, so, it is not necessary to get the Authorization for unimportant equipments of the substation as there are abundant manufacturers who can produce the equipments.

Therefore, we would like to suggest that only the Manufacturer’s Authorization of important/essential equipment, which listed as the following, should be submitted for evaluation :

1. main transformer;

Remove 220kV HV cable from the list and follow the Specifications.

26


2. shunt reactor

3.circuit breaker and disconnector

4.current transformer

5.capacity voltage transformer

6.surge arrestor

7.substation automation system

80 Vol. 2 of 2;



Clause: 1.15.1-Joint Review Meeting

According to the description, the contractor will bear the charger for the joint review meeting for 1 time, if there are any other necessary meetings, the owner and/or engineer should bear the charge for themselves. Please kindly confirm the same.

Bidding Document Volume 2 of 2, Section VI, Technical Specifications section 1.15.1 refers to the joint review meeting only.

81 Vol. 2 of 2;



Clause: 1.20.1-Factory Acceptance Tests

We have the following clarification/suggestion for this clause:

1. As some equipments can be inspect jointly, we want confirm that the inspection time should not fix at 10(ten) but should according to the actual situation;

2. The duration period for the inspection should decided by the actual situation;

3. Please confirm the representatives from the owner and/or engineer side will not exceed 3 persons.

1. Bidders should quote as per the price schedule.

2. Confirmed

3. Correct as described in Bidding Document Volume 2 of 2, Section VI, Technical Specifications section 1.20.1

82 Vol. 1 of 2;


Please confirm the mandatory spare parts listed if for one transformer or two sets?

Please also confirm that the quantity of the whole table is

For one transformer.

27




Item: C-Power transformers

correct and we no need to change it.

83 Vol. 1 of 2;




Item: 6-LV Cables and accessories

Please provide the quantity for the Item 6. To be advised by the Contractor.

84 Vol. 1 of 2;



Appendix 1: Terms and Procedures of Payment

Schedule No. 1.

Ten percent (20%) of the total CIP amount…..

Eighty percent (70%) of the total or pro rata CIP….

Schedule No. 2.

Ten percent (20%) of the total EXW….

Eighty percent (70%) of the total or pro rata EXW….

Schedule No. 3. Design Services

Ten percent (20%) of the total design services…..

Ninety percent (80%) of the total or pro rata design…..

Schedule No. 4. Installation Services

Ten percent (20%) of the total installation services…..

Eighty percent (70%) of the measured value of work performed by the Contractor…..

Please update the description of payment terms as there

TERMS OF PAYMENT

Schedule No. 1. Plant and Equipment Supplied from Abroad

In respect of plant and equipment supplied from abroad, the following payments shall be made:

Twenty percent (20%) of the total CIP amount as an advance payment against receipt of invoice and an irrevocable advance payment security for the equivalent amount made out in favour of the Employer. The advance payment security may be reduced in proportion to the value of the plant and equipment delivered to the site, as evidenced by shipping and delivery documents.

Seventy percent (70%) of the total or pro rata CIP amount upon Incoterm “CIP”, upon delivery to the carrier within sixty (60) days after receipt of documents [Employer to state the required documents, such as a negotiable bill of lading, a non-

28


are many contradictory between capitalization and figure. negotiable sea way bill, an airway bill, a railway consignment note, a road consignment note, insurance certificate, etc.].

Five percent (5%) of the total or pro rata CIP amount upon issue of the Completion Certificate, within sixty (60) days after receipt of invoice.

Five percent (5%) of the total or pro rata CIP amount upon issue of the Operational Acceptance Certificate, within sixty (60) days after receipt of invoice.

Schedule No. 2. Plant and Equipment Supplied from within the Employer’s Country

In respect of plant and equipment supplied from within the Employer’s country, the following payments shall be made:

Twenty percent (20%) of the total EXW amount as an advance payment against receipt of invoice, and an irrevocable advance payment security for the equivalent amount made out in favour of the Employer. The advance payment security may be reduced in proportion to the value of the plant and equipment delivered to the site, as evidenced by shipping and delivery documents.

Seventy percent (70%) of the total or pro rata EXW amount upon Incoterm “Ex-Works,” upon delivery to the carrier within sixty (60) days after receipt of invoice and documents [Employer to state the required documents, such as a railway consignment note, a road consignment note, insurance certificate, etc.].

29


Five percent (5%) of the total or pro rata EXW amount upon issue of the Completion Certificate, within sixty (60) days after receipt of invoice.

Five percent (5%) of the total or pro rata EXW amount upon issue of the Operational Acceptance Certificate, within sixty (60) days after receipt of invoice.

Schedule No. 3. Design Services

In respect of design services for both the foreign currency and the local currency portions, the following payments shall be made:

Twenty percent (20%) of the total design services amount as an advance payment against receipt of invoice, and an irrevocable advance payment security for the equivalent amount made out in favour of the Employer.

Eighty percent (80%) of the total or pro rata design services amount upon acceptance of design in accordance with GC Clause 4.4 by the Project Manager within sixty (60) days after receipt of invoice.

Schedule No. 4. Installation Services

In respect of installation services for both the foreign and local currency portions, the following payments shall be made:

Twenty percent (20%) of the total installation services amount as an advance payment against receipt of invoice, and an irrevocable advance payment security for the equivalent amount made out in favour of the Employer. The advance payment security may be reduced in proportion to the value of work performed

30


by the Contractor as evidenced by the invoices for installation services.

Seventy percent (70%) of the measured value of work performed by the Contractor, as identified in the said Program of Performance, during the preceding month, as evidenced by the Employer’s authorization of the Contractor’s application, will be made monthly within sixty (60) days after receipt of invoice.

Five percent (5%) of the total or pro rata value of installation services performed by the Contractor as evidenced by the Employer’s authorization of the Contractor’s monthly applications, upon issue of the Completion Certificate, within sixty (60) days after receipt of invoice.

Five percent (5%) of the total or pro rata value of installation services performed by the Contractor as evidenced by the Employer’s authorization of the Contractor’s monthly applications, upon issue of the Operational Acceptance Certificate, within sixty (60) days after receipt of invoice.

85 Vol. 2 of 2;



Clause: 22.17.15.1

The detail distance of the road should decided by the actual situation.

Confirmed.

86 Vol. 1 of 2; Please confirm these guarantees are subject to the Confirmed.

31




Page: 254-Advance Payment Security &

Page 259-Performance Security

Uniform Rules for Demand Guarantees, ICC Publication No. 758.

87 Vol. 2 of 2;



Clause: 1.2-Scope of work

As the bidder doesn’t have any contract relationship with the shunt reactors in Rabai Substation, please confirm that the Owner should arrange the supervision of installation from manufacturer side if necessary.

The contractor shall provide a methodology for rellocation of the shunt reactor for approval by the Employer/Employer’s Representative. The employer shall not provide any supervision.

88 Vol. 1 of 2;



Form of Bid Security (Bank Guarantee)

According to the regulation of the Bank, the Bid guarantee should have the accurate expire date, so we suggest to change the clause as follows:

This guarantee will expire: (a) if the Bidder is the successful Bidder, upon our receipt of copies of the contract signed by the Bidder and the performance security issued to you upon the instruction of the Bidder; or (b) if the Bidder is not the successful Bidder, upon the earlier of (i) our receipt of a copy your notification to the Bidder of the name of the successful Bidder; or (ii) twenty-eight days after the expiration of the Bidder’s bid; or(c) Oct 04, 2015.

Confirmed.

89 Vol. 1 of 2;


Section VII: General Conditions ;

As per the GC 4.8.4 and clause 1.7 of Section Ⅲ evaluative and qualification criteria. We supposed that the time for Completion of the whole of the Facilities including pre-commissioning shall be eighteen months from the Effective

Confirmed as provided in Bidding Document Volume 1 of 2, Section III, Evaluation and Qualification Criteria, item 1.7a.

32


Clause: 4.8.4 &

Section III: Evaluative and Qualification Criteria;

Clause: 1.7 &


Clause: GC 2.2.2

Date as described in the Contract Agreement.

Please kindly confirm the Time of Completion shall including the pre-commissioning but not the commissioning.

90 Vol. 2 of 2;



Appendix A-Bid Drawings

Drawing No: PB-KET-2014-L-501

As per the drawing provided by you, we found the existing 220kv overhead line have crossed the construction site of the MARIAKANI substation, so it may heavily influence the construction of the said substation. We suggest to remove the whole project site to south side by reasonable distance to avoid the influence or the employer should remove the said overhead line. Please kindly confirm the same.

In line with Bidding Document Volume 2 of 2, Section VI, Technical Specifications section 3.2.1 paragraph 4 Bidder’s shall follow the designs in Drawings.

91 In what concerns the 500 kVA earting/auxiliary transformer:

a) Bushings type: in item 3.3.2 is requested porcelain with lf 31 mm/kV. The customer's specifications and their data-sheets require plug-in type bushings (Euromold type), protected with air-filled cable box. We ask the attention to the fact that if you really wants bushings with creepage distance of 31 mm/kV, we cannot use plug-in type bushings (Euromold type or similar).

So please confirm the solution that the customer wishes for his project, also confirm if they wants as indicated in client’s Schedules, Cables box in HV and LV sides.

a) Due to the use of plug-in type bushings on the HV side, a cable box may be left out

33


Please note that if we use plug-in type bushings in HV side, doesn’t makes any sense to ask the HV cable box.

b) Electrical characteristics: For a correct design of the earthing/auxiliary transformer, please confirm:

a) Zero sequence impedance (ohm per phase) ?

b) Continuous neutral current (if required) ?

c) In customer specifications and their data-sheets is referred "Current Transformer." If KETRACO really demands current transformers it is necessary confirm the general characteristics (ratio; VA/Class); number of CT’S per phase; immersed in oil inside the tank or outside of the transformer, kind of service (protection or measuring).

b) Sufficient electrical parameters have been provided to Bidders to enable calculations of the requested characteristics.

c) The required CTs are given in the Drawings.

92 Volume 2 of 2;


Clause: 1.2.1


Clause: GC3.4

General:

a. Two existing reactors at RABAI Substation are just to be moved to MARIAKANI substation, or some sort of maintenance is need? If positive please inform what maintenance shall be done

b. Please confirm that all the goods supplied shall be from member countries of the African Development Bank.

c. Regarding the OHL, one tower has to be dismantled and transported to KETRACTO warehouse at site of construction. Please confirm that this is correct and nothing has to be made regarding the foundations.

a. The complete scope of work for the two existing reactors is given in Bidding Document Volume 2 of 2; Section VI: Technical Specifications; Clause: 1.2.1

b. Refer to Section I: Instruction to Bidders; Clause 5.1.

c. Confirmed.

34


93 Vol. 2 of 2;


Clause: 16.1 & 16.5

&


Item M: 11/0.415kv; 500kVA Earthing/Auxiliary Transformers(CAF-CAF);

Page: 627 of 677

&


Appendix A-Bid Drawings:

Drawing No: PB- KET-2014-P-519

Q1: Please clarify the requirement for Limitation and withstanding of fault current in neutral about Earthing Transformers.

From the PART 2 – Employer’s Requirements:Item 16. EARTHING / AUXILIARY TRANSFORMERS,in the Page 271 of

677,it is mentioned that” Earth fault current required

Amp. 1050”、 “Earthing/auxiliary transformers shall be capable of withstanding for a period of 30

seconds”.Meanwhile, From the 4. SCHEDULES OF TECHNICAL INFORMATIONm, Item M:11/0.415kV;500kVA EARTHING/AUXILIARY TRANSFORMERS(CAF-CAF): in the

Page 627 of 677, it is mentioned that” Limitation and

withstanding of fault current in neutral for 30s:1050A”.

However, From the PART 2 – Employer’s Requirements: Item 16. EARTHING / AUXILIARY TRANSFORMERS ,in the

Page Page 273 of 677, it is mentioned that” The resistors shall be rated for 10 seconds and the current ratings and ohmic value shall be as shown in the drawings in Appendix

A.” Meanwhile, in the drawings(PB-KET-2014-P-519) in Appendix A, The resistors limitation and withstanding of fault current is 500A for 10S.

Correct observation, please adjust the maximum short circuit current rating of the earthing/ auxiliary transformer to 500A.

94 Volume 2 of 2;


Clause: 3.2.1

Could you accept the minor change for substation layout in order to optimize the design

In line with Bidding Document Volume 2 of 2; Section VI: Technical Specifications; Clause: 3.2.1; Paragraph 4 Bidders should follow the design in Drawings.

95 We understand that there is no work of 220kV HV cable, please confirm.

Confirmed.

35


96 Does the existing OHL should be kept working during this project construction?

If not, how long of outage can we get?

The existing OHL should be kept energized for as long as practicably possible. Outages will be planned in liaison with KETRACO.

97 Volume 2 of 2;


Clause:3.4-Taxes and Duties;

&


Clause: GC3.4

In Section VII. General Conditions-3.4-Taxes and Duties; and Section VIII. Particular Conditions-GC3.4, please conform which charges/taxes are exempted and which should be in contractor’s quotation. Also, please indicate each rate of duties, taxes, levies and charges may concern.

Refer to TAC1; S. No.: 92 (c)

98 Volume 1 of 2;


Appendix 3

In Section VII. General Conditions-6.4-Insurance; and Appendix 3 Insurance Requirements, please conform Insurance items and provide related rate.

Please refer to Section IX: Contract Forms; Appendix 3 - Insurance Requirements, in addition the following rates apply:

Cargo insurance 110% CIF

Installation All Risks Insurance 100% Contract value

Third Party Liability Insurance – In accordance with the laws of Kenya

99 Volume 2 of 2;


Clause: 14.1

In the technical specification and guaranteed schedule of power transformer, the location of OLTC is LV line terminal. Please clarify whether it is Low Voltage Terminals at HV side or LV side.

The tap changer is on the line end of the LV winding to enable C.F.V.V flux voltage variation with constant tertiary voltage.

100 Volume 2 of 2;


In the technical specification of diesel generator, there is one daily tank. But in the technical guaranteed schedule, there are two tanks, i.e., Bulk fuel tank and Daily service fuel tank. Please clarify the required quantity is 1 or 2.

The number and names of fuel tanks is for information only Bidders are free to propose Diesel Generators that fulfill the specifications.

36


Clause: 21

101 Section VI: Bidding forms - Price Schedules

Section VI: Requirements -Drawings

As per the single line diagram, the quantity of 400kV surge arrester is 30, but in the price schedule, it is 18. Please clarify

Refer to TAC1 Clarification No 17.



As per the single line diagram, the quantity of 400kV post type current transformer is 42, but in the price schedule, it is 54. Please clarify.

Refer to TAC1 Clarification No 18.



As per the single line diagram, the quantity of 220kV post type current transformer is 36, but in the price schedule, it is 57. Please clarify.

Refer to TAC1 Clarification No 6

104 Price Schedule REV2, pages 71 of 1022

"14.1 Vehicle Type 1

14.2 Winch attachment for vehicles

Type 1

14.3 Staff Training & Internship costs"

"Kindly clarify need of line item 14.1 to 14.3 in Schedule 1, we understand that the mentioned activities are to be carried out locally as in services portion & the same has to quote in schedule 4 only.

Kindly confirm our understanding."

Confirmed.

105 "Appendix -1 Terms of Payment", pages 324,325 of 1022

"Terms of payment specified for Schedule 1 to 4 it is mentioned as:

Ten percent (20%) as an advance payment

Eighty percent (70%) of the total upon delivery to the carrier

"As per the payment terms there is an discrepancy between the word & numbers of the percentage mentioned.

Kindly clarify the same."

Refer to TAC1 clarification No 84

37


Five percent (5%) of the total upon issue of the Completion Certificate

Five percent (5%) of the total upon issue of the Operational Acceptance Certificate. "

106 "SECTION VI TECHNICAL SPECIFICATIONS FOR SUBSTATION AND OVERHEAD LINE TERMINATION"

Clause 1.2.1, pp 363 of 1022,

Relocation of Shunt reactor

"We understand that employer will arrange for Supervision/Guidance from reactor manufacturer for the transportation and installation of shunt reactors. The functional operation of the reactor shall be the responsibility of Reactor Manufacturer as its only being relocated from Rabia Substation.

Kindly confirm our understanding."

The warranty is in the owner’s scope however the contractor shall be expected to provide transit insurance and a shunt reactor expert for dismantling and assembling of the shunt reactor. Moreover, the contractor shall also provide a methodology for rellocation of the shunt reactor for approvalby the Employer/Employer’s Representative.


Clause 5.2 Dismantling of 400 kV Extension tower

Request you to provide the distance between Site and Ketraco stores.

The tower is to be dismantled and stored at the warehouse to be constructed by the winning bidder at Mariakani site.


Clause 11.00 UPS

There is no BOQ for UPS under Auxiliary Supplies. Kindly clarify if the same needs to be included along with other equipment/item

This cost should be included in Bidding Document Volume 1 of 2, Section IV Bidding Forms, Price Schedules, item No 5.1


Clause 5.00 Telecommunication

"There is no BOQ in the price schedule for new Telecommunication system to be installed in Mariakani Substation.

Kindly request you to clarify the same. "

This cost should be included in Bidding Document Volume 1 of 2, Section IV Bidding Forms, Price Schedules, item No 5.3

110 "Section VI-Requirement - Technical Kindly confirm whether the dimension & type of the road, The roads within the compound of staff housing shall

38


Specification Civil Works", Clause

22.17.15.1, 353 of 677

Access roads within the substation

within the compound of staff housing, could be considered as 3m & concrete road respectively.

be classified as ‘Access roads within the substation’. Please refer to Section VI: Technical Specifications; Clause 22.17.15.1 - Access roads within the substation.

111 "Section VI-Requirement - Technical Specification Civil Works", Clause

22.17.7.9, 330 of 677

Disposal of Surplus

Kindly provide us the distance of designated area from the substation plot for the disposal of unusable/ unsuitable material.



22.17.15.1, 353 of 677

Main access road from substation to Mombasa road

It is observed during site visit that the scope of approach road from proposed substation plot to nearby highway is about 700m, whereas in as confirmed during site visit & as per specifications, bidder has to quote for 2km bitumen approach road. Hence client is requested to kindly provide either the sectional drawing for each 500m segment of total 2km approach road or standard sectional drawing which will be valid for all along 2km length of proposed approach road.

As for now please follow the specifications, details of the final road layout will be agreed with KETRACO on Contract award.


22.18, 357 of 677

Building Services

Requirement of Fire Alarm, Fire Detection and Fire Suppression system is not clearly mentioned in the specification. It is requested to provide details of specific requirement for Fire Fighting system in all areas i.e. control building, transformer bay, shunt reactor bay, store building etc.

Specific requirements for transformers and reactors are as given in Bidding Document Volume 2 of 2; Section VI: Technical Specifications; Clauses 14.5 and 15.4 respectively. As a general guide Bidder’s should make reference to Bidding Document Volume 2 of 2; Section VI: Technical Specifications; Clause 2.1; Paragraph 9 and Clause 3.2.1.3; Paragraph 2.


22.17.13, 352 of 677

It is stated that the area within the transformer enclosure shall be tested in accordance with Part 19 of Section 5 of QCS. Please confirm whether will it be in accordance to QCS(which is relevant to State of Qatar) or some other

Replace the last statement of Bidding Document Volume 2 of 2, Section VI, Technical Specifications, clause 22.17.13 paragraph 3 with ‘It shall be tested in

39


Oil Containment code. accordance with BS8007.’


22.18.2, 362 of 677

Mechanical Building Services

It is observed during site visit that in existing Rabai substation control room is equipped with split AC system whereas under the mentioned clause specification is stating about installation of complete HVAC system for building. Please confirm which system to be adopted for current tender i.e. Mariakani Substation and in case of HVAC system kindly indicate the spaces allocated for Air Handling units and related accessories in the substation layout plan.

The Bidders should follow the Specifications.


The capacity of each main transformer in Bidding document(P485) is 450MVA, which is inconsistence with the value in Price schedules(200MVA). Would you please make sure which value is right?

Bidding Document Volume 2 of 2, Section VI, Technical Specifications, clause 10.2.1.1 should read as follows, ‘Mariakani 400/220kV substation. New 400kV and 220kV AIS including OHL feeders and 2x200MVA interbus auto-transformer

117 Vol. 2 of 2;




The quantity of 400kV arrester in Bidding document is 30, which is inconsistence with the valve in Price schedules(18), Would you please make sure which value is right?


118 Section VI: Bidding forms – Price schedules

Schedule 1: Item no. 2.8

Item 2.8 in Price schedule 1 is about 220kV Under-hung Post insulator, and the quantity is 24 sets shown in this schedule. But according to the layout of 220kV busbar, these device are not necessary for Mariakani SUB.


40



119 Section VI: Requirements – Technical specifications

Clause 8.2.1.1 (b)

Chapter 8.2.1.1 mentioned “Former Rabai –Kiambere 220kV OHL shall be reconfigured as Mariakani – Rabai 3.” Please clarify whether the 220kV line protection equipments in Mariakani S/S are shifted from Rabai S/S, and describe the detailed protection configuration for this line.

No protection equipment will be transferred from Rabai and Kiambere, refer to Tender drawings for protection requirements

120 Length of line Please inform us the length of each 400kV line and 220kV line, and detailed communication configuration for all opposite substations of each 400kV line and 220kV line, so that the number and type of communication devices can match each other after they are put into operation.

The length of Mariakani-Isinya line is 405km and the length of Mariakani-Rabai line is 24km. the other lines’ length are not available at the moment however will be made available on Contract award.

121 Vol. 2 of 2;



Clause: 22.11

According to the meeting minutes, water supply system should be led by 19 km pipeline, please clear the distance, the pipe specification, material and installation method, and please let us know the water pressure of water source.


122 "SLD 220kV Price Schedule"

Disconnector

"On diameter 3, S98 & S114 is represented with one earthing switch with no name. This is inconsistent with the other diameters;

Please confirm that S98 & S114 of diameter 3 is a simple disconnector, with no earthing switch.

Consequently, the quantities in the price schedule should be :

twelve (12) disconnectors with no earthing switch instead

Earth switches attached to S98 and S14 were erroneously left without numbers, nevertheless they are still part of the scope to enable the future connection of IBTs 3 and 4

41


of ten (10),

fifteen (15) disconnectors with one earthing switch instead of seventeen (17),

and four (4) disconnectors with two earthing switches.

Please confirm."

123 Price Schedule

Power transformers,

Spare Part

It is written "Power transformers (for one 400kV)". As they are 2 power transformers, does this mean that the quantities are to be multiplied by 2 for the calculation of the total price of the project?


124 "400kV layout Price Schedule"

Surge arresters

"As per Price Schedule & table of 400kV layout, it is requested to supply eighteen (18) Surge Arresters 400kV.

However, as per 400kV SLD & Layout, thirty (30) Surge Arrester are represented.

Please confirm that the right quantity is thirty (30) Surge Arresters."


125 Section VI "Technical specifications for substation and OHL Termination

"§1.2.1

p.17 of 677"

"In the chapter 1.2.1, it is stated that : "" The future bays shall be constructed as ‘Skeleton bays’, i.e. full gantry structures but no electrical equipment (or associated electrical plant foundations) except the following is required : ( The overhead conductors, i.e. earth wire, bus 1 and 2 and the respective high level transfer , conductors , Earth wire, Earth grid, Drainage , Cable trenches, Levelled site complete with stone chip ) ""

This statement remain the same for both 400kV and 220kV.

Confirmed.

42


Please confirm that structures and foundations of electrical equipements shall not be supplied for these skeleton 400kV and 220kV future bays."


"§ 3.2.1.9.1

p.58 of 677"

"In remote position, the circuit breaker and the disconnectors are electrically interlocked.

In local position, the circuit-breaker and the disconnectors are electro-mechanically interlocked, with an electro-bolt.

No exchange box with keys shall be supplied.

Please confirm. "

Bidders are required to provide a fully functional interlocking system in line with Bidding Document Volume 2 of 2, Section VI, Technical Specifications, clause 3.2.1.9

127 Section VI "Technical specifications for substation and OHL Termination, datasheet

§14.1 p.222 of 677 §14.3.9 p.231 of 677

"In the Chapter §14.1 it is stated:that ""Unless specified otherwise, autotransformers fitted with an OLTC shall have this located at the LV line-end"" whereas in Chapter § 14.3.9 it is stated that ""Unless otherwie specified, transformes with an HV Um equal to 36kV or higher shall be equipped with an on-load tap changer (OLTC) on the high voltage winding"".

Please confirm that OLTC shall be on the LV side. (as written also in the technical datasheet)."

Confirmed as given in the datasheet.


§ 14.5 p.239 of 677

"Fire protection : It is stated : ""It may be necessary to provide integral protection for some transformers depending on the application, site and rating.""

Please confirm that there is no fire protection to be

For the power transformer, the contractor must provide an integral fire protection system with ‘Explosion Prevention’ characteristics. The system should offer the following features:

· Very rapid tank depressurisation.

43


provided for the power Transformer." · Separation of evacuated gasses from air.

· Separation of the gasses from oil.

· Channelling of the evacuated gasses away from the transformer environment.

· Nitrogen injection.

The transformer tank and installation shall be provided with the necessary flanges and valves for direct fitting of the system.

129 Section VI "Technical specifications for substation and OHL Termination, Datasheet

§ A1.7 p.411 of 677 § K1 p.597 of 677

"As per the power transformer datasheet page 597 of 677 chapter K.1., the rated power frequency withstand voltage values are defined as:

- HV Terminal (design value only): 460kV

- HV Test value (IVPD enhancement level): 416kV

- HV Test value (IVPD PD measurement): 365kV

whereas in page 411 of 677 chapter A.1.7, the rated power frequency withstand voltage (at altitude <1000m) indicated is :

- Phase to earth : 520kV

- Phase to phase : 520kV

- Accross the isolating distance : 610kV

Please clarify.

Please use Bidding Document Volume 2 of 2, Section VI, Schedules of Technical Information, item K. Item A refers to general switchgear specifications which are not otherwise mentioned with the values

44


Please also clarify if the values are given for the terminals only or also for the windings."

Voltages vary along the winding hence terminal values are expected to mean full winding values.

130 Section VI "Technical specifications for substation and OHL Termination", 400kV SLD, 220kV SLD

"§ K1 p.599 of 677

§ A1.8 p.411 of 677"

"According to following tender document chapter K1 and A1.8 respectively in page 599 and 411, the short circuit currents are defined as :

- 50kA/2s for HV terminals and windings (400kV) according to the transformer datasheet

- 40kA/1s for 400kV switchgear according to the general datasheet and SLD

Please clarify : what is the short-circuit current to be taken into account for 400kV?"

Please use the short circuit value of 40kA for 400kV and 31.5kA for 220kV.

131 Section VI "Technical specifications for substation and OHL Termination", 400kV SLD, 220kV SLD

§ K1 p.599 of 677 § B1.7 p.433 of 677

"According to following tender document chapter K1 and B1.7 respectively in page 599 and 433, the short circuit currents are defined as :

- 40kA/2s for LV terminals and windings (220kV) according to the transformer datasheet

- 31,5kA/1s for 220kV switchgear according to the general datasheet and SLD

Please clarify : what is the short-circuit current to be taken into account for 220kV?"

Please use the short circuit value of 40kA for 400kV and 31.5kA and 220kV.

45


132 Section VI "Technical specifications for substation and OHL Termination"

"- No information is given for 11kV short-circuit current to take into account for the transformer tertiary winding and terminals, nor for auxiliary transformer.

Please confirm that, as specified for 11kV Cable, the short circuit for 11kV equipement design shall be 15,7kA/1s."

Symmetrical short circuit current for auxiliary transformer HV terminal is given in Bidding Document Volume 2 of 2, Section VI, Schedules of Technical Information, item M as 25kA.

133 Section VI "Technical specifications for substation and OHL Termination", price schedule

Neutral Earthing Reactor

§ 16.5 p.274 of 677

"The Requirement Technical Specification Section VI, §16.5 page 274/677 mentions a neutral earthing reactor for the two Isinya lines.

But, according to 400kV SLD neither Price schedule, no neutral earthing reactor is present on the four lines (Isinya 1/2 and Dongo Kundu 1/2).

Please confirm there is no neutral earthing reactor to supply for each line."

Add item 11.7 Neutral earthing reactor, Nos 2 to Bidding Document Volume 1 of 2; Section IV: Bidding Forms; Price Schedules: Schedules No 1 and 4.


FAT

§ 1.20.1 p.32 of 677

"Please confirm that all the requested FAT are listed in the paragraph 1.20.1 page 32, and that this paragraph prevails on following ones, specific to each equipement.

For instance, there will be no FAT for shunt reactors.

There will be no FAT for 11kV Cable, Auxiliary transformer, etc."

Bidding Document Volume 2 of 2, Section VI, Technical Specifications, clause 1.20.1 shall be changed to read as, “The equipment listed below shall require eleven (11) FATs.” Also add shunt reactors to the list of equipment which needs FATs

135 "Section VI ""Technical specifications for substation and OHL Termination"" and 400kV Layout and elevation,

Section III"

"According to the employer's requirement, ""The bidder's main offer should comply with the principles shown in the bid drawings other arrangements being submitted solely as alternatives to the main offer"".

Please confirm that, contrary to section 3 ""Evaluation and

Bidding Document Volume 1 of 2, Section III Evaluation and Qualification criteria item 1.1, Alternative proposal is not applicable.

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Installation

"§ 3.1 p.56 of 677

qualification criteria"" §1.1, alternative installation solutions can be offered."


Telecommunication, § 9 p.116 of 677

Please confirm whether telecommunications systems shall be provided on every line except future ones.

Correct as given in Bidding Document Volume 2 of 2, Section VI, Technical Specifications, clause 1.2.1



"Please inform on the approximative lengthes of lines :

- Mariakani - Malindi

- Mariakani - Dongo Kundu

- Mariakani - Kiambere"

Mariakani – Malindi is approximately 124km.

Mariakani - Dongo Kundu is approximately 50km.

Mariakani - Kiambere is approximately 500km.



"If all lines shall be equipped with telecommunications, please confirm that each

single circuit line will be equipped with 1 x OPGW guard wire for telecommunication purposes (24 fiber OPGW).

Connection to OPGW will be performed in a fiber optic connection panel set at the foot of the incoming line gantry and out of the present scope of supply.

OPGW fiber optic characteristics are supposed to be the same as the one described in § 9."

All the lines shall be equipped with 48 fiber OPGW.

139 220kV detailed SLD, 400kV SLD, Schedule of technical specification

Neutral earthing resistors, Auxiliary

"SLDs show a neutral earthing resistor designed 500A 10s, whereas the technical datasheet for the auxiliary transformer (M.) show a limitation and withstanding of fault current in neutral of 1050A 30s .

Refer to TAC1 clarification No 93.

47


transformer

§M p. 627 of 677

Please confirm that 500A 10s is to be considered for the neutral earthing resistor and for the auxiliary transformer."


Diesel Generator

§ 21.1 p.313 of 677

"""The generator shall be located in a separate building complete with fire protection"".

Please confirm that hand extinguisher complies with your requirement."

Use similar fire protection system designs similar to the ones to be installed in the Control building.

In addition, the generator fire protection shall also include:

12kg Automatic dry powder fire extinguisher gas cartridge type in metal casing and fixed to roof slab. Unit as 'Eversafe' or equal and approved with contents gauge sprinkler head and discharge nozzle for the Genset and switch room.

9 kg dry powder fire extinguisher gas cartridge type in metal casing and mounted on wall surface. Unit as 'Angus' ABC all purpose powder or equivalent and approved with content gauge. With a fire rating of 55B.

141 Limit of supply "Please clarify the limit of supply on Dongo Kundu 1&2, 400kV lines : we understand that we supply the equipment but no overhead cable nor tension set to be installed on the landing gantry, nor downleads.

(Please refer to ""Images"" sheet)."

Confirmed. Dongo-Kindu 1 and 2 lines will be constructed after completion of this lot.

142 Limit of supply "Please clarify the limit of supply on 220kV lines: except for Rabai 1&2 : we understand that we supply the equipments but no overhead cable nor tension set to be installed on the landing gantry, nor downleads.

(Please refer to ""Images"" sheet)."

Confirmed. Dongo-Kundu 1 and 2, Rabai 3, Malindi and Kiambere lines will be constructed after completion of this lot.

48


143 "Section VI ""Technical specifications for substation and OHL Termination"",

Substation location plan"

OHL, §23, p.373 of 677

"As per the substation location plan, we understand that there is no tower to be built or modified and no civil work to be done; only one tower has to be dismantled, and some conductors and strain strings have to be reused and relocated on landing gantries of the substation.

Please confirm."

Confirmed. However the foundation should be demolished to ground level.

144 Section VIII - Particular Conditions

Warranty / Defect Liability

"§ GC 5.2.2 p.3-231

§ GC 5.2.10"

"As per Section VIII-Particular Condition § GC 5.2.2 page 3-231 , the extended defect liability requested for the critical component is twenty four (24) months from the Operational Acceptance.

However, as per the note * page 3-233 of Section VIII-Particular Condition § GC 5.2.10 page 3-231, the extended defect liability requested for the critical component is sixty (60) months from the Operational Acceptance.

Please confirm that :

- The extended defect liability for the critical components is 48 months starting after the original defect liability."



11kV cable link,

"According to the specification, the following test is required:

""HVAC field acceptance test :

Please substitute the statement in Bidding Document Volume 2 of 2, Section VI, Technical Specifications, clause 18.4.5.3 with, “The field acceptance tests shall be in accordance with section 20 of IEC60502-2.”

49


§18.4.5.3 p.284 of 677 An AC overvoltage of 2,0Uo will be applied to each phase of the cable system for a period of not less than 1h""

IEC 60502-2 indicates that two different methods can be used for AC test :

- either apply the phase to phase voltage of the system between the conductor and the metallic screen for 5minutes.

- or apply the normal operating voltage of the system for 24h.

Please confirm that both methods are acceptable, and that the contractor can choose to apply the normal operating voltage of the system for 24h (soak test)"

146 Section VI " Requirements Technical specifications "

Power Transformer

§14.3 p.223 of 677

Please clarify what do you mean by "vibration tests" ? Vibrations tests are as given in IEC60076-6 clause 7.8.13

147 Vol. 2 of 2;


Section VI: Requirements-Technical Specifications; Clause: 22.8

In what concerns the finishing ground level of the substation area needs to be at a uniform level that is the same level as the base of the 400kVA pylon tower or the level “0” of the Substation must have another reference?

Refer to TAC1 clarification No 39.

148 Volume 2 of 2 : Section VI, Technical Specifications, clause 22.5.2

In Section VI - Requirements Technical Specifications, it is said “At Mariakani substation a store with a usable space area of 1600 square metres will be built.” But in the Price Schedules, there is no item about store. Please clarify about it. If it is contractor’s duty to build store, where to locate it?

Bidders are required to build a store whose details are given in Bidding Document Volume 2 of 2, Section VI, Technical Specifications, clause 22.5.2

Please add to Bidding Document Volume 1 of 2, Section IV Bidding Forms, Price Schedules, in Schedules 2 item 14.6 Warehouse/ Store 1Nos and

50


Schedule 4 item 14.7 Warehouse/ Store 1Nos respectively.

149 Vol. 2 of 2;




Please provide the flood water level and the water logging level of the site area, if not, can we assume that site is not affected by the flood water level effect?


150 Appendix B “EXISTING TELECOMMUNICATIONS AND OPGW SYSTEMS”

and

SECTION VI

1.4 Terminal Points “The telecommunications system is to be fully integrated into the existing telecommunications system”

In appendix B “EXISTING TELECOMMUNICATIONS AND

OPGW SYSTEMS”，Drawing No. 500，501，502，503 is 2009 system diagram, it can’t accurately reflect the current status. Please provide more details of the latest telecommunication system and OPGW cable, and clarify MARIAKANI 400kV substation how to access the existing telecommunication system.

Please provided the existing telecommunication equipment

manufacturers，type，capacity，quantity，list and description of the related remote substation, NCC and

RCC；whether the existing equipment can be utilized；the

existing channel assignment；the detailed

telecommunication equipment requirements：such as

type，capacity，quantity，list for substation, etc.

Bidders should follow the Tender drawings.

The requested details are found in the tender drawings referred to by the Bidder in the first part of the Bidder’s query.

51


151 TECHNICAL SPECIFICATIONS

SECTION VI

22.11 Water, Electricity and Other Services

22.12 Inclement Weather

In 22.11,“Local water connection point is 4km distance,”

In 22.12,“Local water connection point is 2km distance,”

Please confirm local water connection point is 2km or 4km distance.


Documents

CLARIFICATIONS SOUGHT BY PROSPECTIVE BIDDERS€¦ · According to the 400kV single line diagram, CVT of transformer bays are single phase. We recommend CVT are equipped for each phase,