17/09/2014 - ARTC - Extranet Waivers/EW_TC... · There is a proposed 22kV double circuit over-head ... The structure capacity requirements for ... This comparison was achieved by

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CONSOLIDATED POWER PROJECTS AUSTRALIA PTY LTD

Adelaide | Sydney | Melbourne

Head Office: 205 Halifax Street ADELAIDE SA 5000 ABN: 18 075 411 219

Telephone: (08) 8291 7800 Facsimile: (08) 8291 7801

Web: www.conpower.com.au Email: [email protected]

FRM-A005 Page 1 of 2 Printed: 5-Sep-14

Ver 30 Jan 12 10506 - ARTC RA Report - 3.09.14.Docx 10:58 AM

Risk Assessment Report

Venue: Consolidated Power Projects Office – Halifax Street, Adelaide

Date of Workshop: 28th August 2014

Facilitator: Grant Johnstone

Participants:

Name Organisation Position

Peter Prasad ARTC National Bridges & Structures

Engineer

Gary Templeton ARTC Project Engineer Third Party

Richard Combe ARTC Project Delivery Manager

David ARTC

Grant Johnstone Consolidated Power Projects Project Manager

Brad Furness Consolidated Power Projects Project Engineer

William Battle Jacobs (Owner’s Engineer) Senior Electrical Engineer

Charles Barrett Jacobs (Owner’s Engineer) Senior Executive Consultant

Peter Faggion Jacobs (Owner’s Engineer) Executive Engineer

RA Objective: To identify if deviating from ARTC's PYSO2 standard to AS/NZS 7000: 2010

does not introduce additional safety risks or increase safety risks to ARTC Operations.

RA Summary:

There is a proposed 22kV double circuit over-head transmission line to be constructed between

the new Broken Hill Solar Plant site and Broken Hill 220/22kV substation. This will require the

crossing of a section of ARTC’s East-West rail corridor at approximately 388.5km.

The structure capacity requirements for rail corridor crossing structures, as laid out in PYS02,

result in over-design. Because of this, CPP applied to ARTC for an engineering waiver to allow

for a more economical solution by designing the structure capacity in accordance with AS/NZS

7000: 2010 for the maximum ultimate limit state return period of 400 years (100 year design

working life and line security level III). ARTC responded on the 20/08/2014, that they were

willing to issue a waiver in this case, subject to the outcomes of a risk assessment and the

completion of the waiver application process.

The intent of the risk assessment conducted on the 28/08/2014 therefore, was to identify and

assess risks to ARTC associated with designing rail corridor crossing structure capacities to

AS/NZS 7000: 2010 for the maximum ultimate limit state return period of 400 years.

Consolidated Power Projects

FRM-A005 Page 2 of 2 Printed: 5-Sep-14

Ver 30 Jan 12 10506 - ARTC RA Report - 3.09.14.Docx 10:58 AM

CPP’s current design places structures sufficiently far away from the rail corridor so that

structure failure will not result in a track fouled by a fallen structure. As a means of ensuring

that the final design maintains this principle, a pole fouling the track was recorded as a risk

(Risk 1) in the risk workshop. The control measure agreed to was that adjacent structures

would be designed to be placed at least fifty (50) metres from the track.

Because the control measure in Risk 1 ensures no structure can foul the track, the worst case

scenario under failed structure condition would be conductor across the track. The workshop

then proceeded to determine the risk level relevant to this situation. The hazard for ‘Risk 2’

was thus recorded as “Conductor falling across track”. Taking into consideration the track

circuiting arrangement (ABS in this case), the earth fault protection systems at the substation

and the low physical threat aluminium conductor would pose to a train travelling at 115kph,

the outcome of the risk assessment of ‘Risk 2’ was a very low risk level (1D) for a conductor

across the track condition at the location under consideration.

With a low risk level determined for structure failure, regardless of the basis for structure

capacity design, the workshop then looked to establish a clear comparison of reliability

between structures designed to PYS02 and those designed to AS/NZS 7000: 2010. The

intention was to see if there was increase in risk level if designing to AS/NZS 7000: 2010

compared to designing to PYS02. This comparison was achieved by assessing the risks of pole

failure for both design approaches separately. ‘Risk 3” identified and assessed risks associated

with designing structures in accordance with the requirements of PYS02 and ‘Risk 4’ identified

and assessed risks associated with designing structures in accordance with the requirements of

AS/NZS 7000: 2010.

Ultimately the comparison was reduced to a comparison of ‘likelihood’ of failure, and in both

cases the ‘likelihood’ outcomes were very low. The outcome of this comparative exercise

therefore highlighted that shifting from designing structure capacity in accordance with PYS02

to AS/NZS 7000: 2010 presents negligible increase in risk to ARTC.

Because AS/NZS 7000: 2010 does not specifically deal with the conductor sag requirement

stated in clause 4.1 of PYS02, to make it clear that CPP designs satisfy this requirement, one

last scenario was assessed, that being “Conductor clearance infringement over track” (Risk 5).

This assessment gave rise to an ‘additional control’, to design to a specified structure

deflection limit so as to maintain required conductor clearance over the track under failure

containment conditions described in clause 4.1 of PYS02.

In conclusion, the risk assessment workshop did not identify any new hazards or significant

increases in risks associated with designing the structure capacity for the rail corridor crossing

in accordance with AS/NZS 7000: 2010 for the maximum ultimate limit state return period of

400 years, when compared to designing the structure capacity for the rail corridor crossing in

accordance with PYS02. Risks in all cases are very low.

ARTC Risk Assessment - Context Setting

CONTEXT SETTING

1. Background

CPP proposes to design the Broken Hill rail crossing in accordance with ARTC document PYS02, except for the structural capacity requirements. Rather than design in accordance with PYS02 Sections 4.1 and 4.8 it is proposed the structures will be designed in accordance with AS/NZS 7000: 2010 for the maximum ulitmate limit state return period which is 400 years (this equates to 100y design working life and line security level III)

2. Risk Statement

Designing the pole structural capacities for poles immediately adjacent to the ARTC track in accordance with PYS02 (factors of safety), will result in structures that will be over-designed.

3. Risk Assessment Objectives

To identify if deviating from ARTC's PYSO2 standard to AS/NZS 7000: 2010 does not introduce additional or increase safety risks to ARTC Operations.4. Critical Success Factors of the activity/proposal being assessed

The main critical success factor is maintaining adequate safety and reliability of the ARTC crossing.

5. Scope (inclusions and exclusions)

Risk assessment associated with designing the stucture capacities in accordance with Australian Standards as apposed to PYS02 (factors of safety, sections 4.1 and 4.8). Construction risk assessment is excluded (to be undertaken later).6. StakeholdersCPP, ARTC, Train Operators, AGL, Public At Large, Rail Safety Regulator

7. Stakeholder consultation

ARTC, Jacobs, AGL, CPP

8. Assumptions

PYS02 (factors of safety) is a legacy based on working stress methodology. The design to be as per PYSO2 with the exception of clauses 4.1 and 4.8.

9. Constraints

OHL easement constraint.Design ConstraintEnvironmental constraints (footprint limitations)10. Boundaries/interfaces

Electric Aerials Crossing ARTC Infrastructure

11. Qualifications/conditions

12. Reference documentation and standards

PYS02, AS/NZS 7000:2010, CPP document '10506-ATRC PYS02 Updates V22014072014.doc', Jacobs design endorsement letter

13. Other clarifying commentary

None

ARTC_SFAIRP_RA

1.0 Risk No.

1.01Risk Category: 1. Safety2. Assets3. Financial4. Environment5. Regulatory6. Reputation

1.1Hazard or

scenario or circumstance

1.2Caused by

2.0 Existing Control

2.01Control type

2.2Current

consequence

2.3Current

likelihood

2.4Current risk

level

5.0Has this workshop adequately addressed this risk?

5.2Comments / clarification

Pole design places 26 metre tall poles at least 50 metres from track

Engineering/ Design

Yes

3.1 BENEFIT

3.2COST

3.3Decision

3.4Responsible

Party

3.5By when

Yes

1.0 Risk No.


1.1Hazard or


1.2Caused by


2.01Control type

2.2Current

consequence

2.3Current

likelihood

2.4Current risk

level



ARTC track circuiting arrangments.Engineering/

DesignYes

AGL line protection and monitoring systems.

Engineering/ Design

AGL line maintenance regimes Administrative

3.1 BENEFIT

3.2COST

3.3Decision

3.4Responsible

Party

3.5By when

Yes

2. ANALYSIS AND EVALUATION

4. RESCORE TO REFLECT SFAIRP OUTCOMES

2.1Responsible Party / Comments

Rare LOW (1D)

5. VALIDATION AND CLARIFICATION

5.1Do the

decisions make sense?

Engineering/Design control negates the need to assess worst case scenario. 26 metre tall poles placed at least 50 metres from the track thereby eliminating the risk.

1.3Leading to an Outcome

3. PROPOSED ADDITIONAL RISK TREATMENT

4.2Revised risk

level

4.1Revised likelihood

Derailment

Broken Hill Solar Plant Connection Rail Crossing - Engineering Waiver RA - 28/08/2014

1. RISK IDENTIFICATION

Worst Case (Credible) Outcome

Damage to rail

Pole failure under excessive load or material degradation.

Most Likely (Credible) Outcome

3.01Control type

Not Significant

CPP - Brad Furness

SFAIRP TEST

1. RISK IDENTIFICATION 2. ANALYSIS AND EVALUATION 5. VALIDATION AND CLARIFICATION1.3

Leading to an Outcome2.1

Responsible Party / Comments

Safety1If failure of pole fouls the track

4.0Revised

consequence

3.0 Proposed Additional Control

2 SafetyConductor falling across track

Structure failure or broken conductor



Halt to train services/train delays

Damage to passing train, potential injury to passengers.

ARTC - Gary Templeton Confirm

Not Significant Unlikely LOW (1D)

Not necessary to assess worst case scenario as historical data points to low risks of broken conductor across tracks. AS/NZS 7000: 2010 design for structures is based on reliability (risk of failure).

AGL

5.1Do the


3. PROPOSED ADDITIONAL RISK TREATMENT 4. RESCORE TO REFLECT SFAIRP OUTCOMES


3.01Control type

SFAIRP TEST4.0

Revised consequence


4.2Revised risk

level

Major Rare #REF!

AGL

Pg 1 of 3 ARTC_SFAIRP_RA

1.0 Risk No.


1.1Hazard or


1.2Caused by


2.01Control type

2.2Current

consequence

2.3Current

likelihood

2.4Current risk

level




DesignYes


Engineering/ Design


3.1 BENEFIT

3.2COST

3.3Decision

3.4Responsible

Party

3.5By when

Yes

1.0 Risk No.


1.1Hazard or


1.2Caused by


2.01Control type

2.2Current

consequence

2.3Current

likelihood

2.4Current risk

level




DesignYes


Engineering/ Design


3.1 BENEFIT

3.2COST

3.3Decision

3.4Responsible

Party

3.5By when

Yes

AGL


Complying with PYSO2






Leading to an Outcome


Not Significant Rare LOW (1E)

ARTC using Transport for NSW standard - EP10010005SP. No one in the workshop is aware of any pole failures.

AGLAGL

5.1Do the




3.01Control type

SFAIRP TEST4.0

Revised consequence


4.2Revised risk

level

#REF!

1. RISK IDENTIFICATION 2. ANALYSIS AND EVALUATION 5. VALIDATION AND CLARIFICATION

3 Safety Failure of Pole

1.3Leading to an Outcome


4 Safety Failure of PoleComplying with AS/NZS 7000: 2010






AS/NZS 7000: 2010 design for structures is based on reliability (risk of failure)AGL


4.2Revised risk

level

5.1Do the




3.01Control type

SFAIRP TEST4.0

Revised consequence

#REF!



1.0 Risk No.


1.1Hazard or


1.2Caused by


2.01Control type

2.2Current

consequence

2.3Current

likelihood

2.4Current risk

level



Design in accordance with PYS02Engineering/

DesignYes

3.1 BENEFIT

3.2COST

3.3Decision

3.4Responsible

Party

3.5By when

Yes


Leading to an Outcome2.1

Responsible Party / Comments

5 Safety

Conductor clearance infringement over track

Structure deflection due to broken conductor in adjacent spans



CPP - Brad Furness



Track clearance provided shall satisfy the requirements of PYS02.


4.2Revised risk

level

5.1Do the




3.01Control type

SFAIRP TEST4.0

Revised consequence



CONSOLIDATED POWER PROJECTS AUSTRALIA PTY LTD

Adelaide | Sydney | Melbourne

Head Office: 205 Halifax Street ADELAIDE SA 5000 ABN: 18 075 411 219

Telephone: (08) 8291 7800 Facsimile: (08) 8291 7801

Web: www.conpower.com.au Email: [email protected]

FRM-A005 Page 1 of 2 Printed: 7-Aug-14

Ver 30 Jan 12 10506 - ARTC PYS02 Updates V2 2014072014.Docx 2:40 PM

MEMORANDUM

To: Peter Faggion (Jacobs) Date: 07/08/14

From: Brad Furness Project No: 10506

cc: Grant Johnstone, Frank Salandra CPP File Ref: FRM-A005 Memorandum.doc

Subject: Transmission Line Railway Crossings

The standard for design of overhead electrical lines is AS/NZS 7000: 2010 Overhead line

design – Detailed procedures.

With reference to the ARTC document PYS 02 (Issue 1, Revision 2), CPP recommends updates

that are in accordance with AS/NZS 7000: 2010 should be incorporated into the document.

These updates are outlined below and will be incorporated in the current CPP project – Broken

Hill Solar Farm Connection.

General Comments

The references to HB c(b)1-1999 in PYS 02 should be updated to AS/NZS 7000: 2010.

The strength requirements for OH line design in PYS 02 require very conservative load factors

when used with ultimate design loads (in accordance with HB c(b)1-1999 and AS/NZS 7000:

2010). It is noted that the origins of load factors in PYS 02 are in accordance with working

stress methods where the working stress applied loads used in design are much less than

ultimate design loads. It is recommended to update the strength requirements for OH lines to

limit state methods in accordance with AS/NZS 7000: 2010. (Section 8 of this standard

outlines the design standards, corrosion protection and testing requirements for all structural

supports).

PYS is silent on the reliability requirement for OH lines. In accordance with AS/NZS 7000:

2010, the reliability of a transmission line is determined by assigning a minimum design return

specified in AS/NZS 7000: 2010 Table 6.1. It is recommended to use the most reliable return

period for structures adjacent to railway line, which is 400years. This equates to a design

working life of 100years and the highest line reliability factor III.

PYS02 Section 4.1 - Structures

Failure Containment Structure Capacities

The second paragraph states that:

“All structures supporting a span of electric aerials over ARTC railway tracks shall be designed

and maintained to achieve 50% of the applicable safety factor nominated in section 4.8 –

(Factors of safety) when two-thirds of the conductors in the span adjacent to the crossing span

are broke”.

It is recommended to update the failure containment requirements to be in accordance with

AS/NZS 7000: 2010 Section 7.2.7.1 Failure Containment Loads Fb. A summary of the

requirements is:

The ultimate capacity of the structure shall not be overloaded for Failure Containment

Loads

Consolidated Power Projects

Memorandum (continued)

FRM-A005 Page 2 of 2 Printed: 7-Aug-14

Ver 30 Jan 12 10506 - ARTC PYS02 Updates V2 2014072014.Docx 2:40 PM

The minimum coincident wind pressure for Failure Containment Loads shall be 0.25

times the ultimate design wind pressure.

Suspension/intermediate structures

For a single circuit support, the number of broken conductors to be considered is

one broken phase (with allowance for bundles) or the earthwire broken.

For a double circuit support, the number of broken conductors to be considered

is the worst loading combination of either any two phases broken, or any one

phase and the earthwire broken.

Tension/strain structures to be designed to withstand equivalent longitudinal load of

one broken earthwire together with one broken phase per circuit.

Distribution systems

Structures using pin or post insulators with wire ties or equivalent fixing, and

relatively flexible structures and their foundations, it is not necessary to design

supports broken conductors.

For tension and terminal distribution pole supports consideration should be given

for broken conductors.

Failure Containment Clearances

The second paragraph also states:

“The sag of the remaining conductors shall not infringe the applicable clearances nominated in

section 4.4.6 – Conductor Heights”.

It is recommended to add to this paragraph that the temperature of the conductor when

determining the ground clearance is to be in accordance with the failure containment

conductor temperature (typically between 50C to 150C).

PYS 02 Section 4.8 – Factors of Safety

As mentioned above in General Comments, it is recommended to update the safety factor

requirements in section 4.8 to be in line with AS/NZS 7000: 2010, where a limit state

approach is adopted using appropriate load factors and strength reduction factors.

Jacobs Group (Australia) Pty Limited

Level 5, 33 King William Street

Adelaide SA 5000 Australia

PO Box 8291

Station Arcade SA 5000 Australia

T +61 8 8424 3800

F +61 8 8424 3810

www.jacobs.com

Jacobs Group (Australia) Pty Limited ABN 37 001 024 095

Jacobs® is a trademark of Jacobs Engineering Group Inc.

Filename: AGL Broken Hill OHL OLX Endorsement 1

Adam Mackett AGL Energy Ltd L22, 101 Miller Street North Sydney 2060

18 August 2014 10506

Broken Hill 22kV ARTC crossing – CPP Memorandum FRM-A005 (DRAFT)

Dear Mr. Mackett

With reference to the 22kV OHL crossing of the ARTC railway using AS/NZS 7000 (level III) as

the basis, Jacobs has reviewed the submitted design information by CPP in addition to the above

referenced memorandum and has the following observations:

Jacobs agrees with CPP’s assessment that references to HB C(b)1-1999 should be

replaced with AS/NZS 7000: 2010.

Jacobs has reviewed drawings BH-CPP-EL-DWG-0612/0613. These drawings provide

information on the ultimate design loads and conform to the load combinations specified

in AS/NZS 7000 including provisions for broken wire conditions. Jacobs concurs with

CPP’s conclusion that Rail crossings should use the criteria of a 100 year working life and

level III security per AS/NZS7000. 100 years is the maximum longest return period

required by AS/NZS 7000 and Security Level III is the most stringent security level.

In conclusion the CPP Broken Hill design of the rail crossing on Drawing BH-CPP-EL-DWG-0204

conforms to AS/NZS 7000 and Jacobs endorses the use of AS/NZS 7000 as the basis of design.

We hope the above is clear, please feel free to contact us with any questions/ comments you may

have in relation to the above.

Regards,

Bill Battle, PE | Jacobs SKM | Senior Electrical Engineer - Transmission Lines, ANZ Resources &

Power | P: +61 8 9469 5053 | M: +61 431 517 005|

[email protected] | www.jacobsskm.com PE, NCEES, BE Electrical, MIEAust CPEng

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17/09/2014 - ARTC - Extranet Waivers/EW_TC... · There is a proposed 22kV double circuit over-head ... The structure capacity requirements for ... This comparison was achieved by