Risk Assessment Report

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4 CONSOLIDATED POWER PROJECTS AUSTRALIA PTY LTD Adelaide Sydney Melbourne Head Office: 205 Halifax Street ADELAIDE SA 5000 ABN: Telephone: (08) Facsimile: (08) Web: Risk Assessment Report Venue: Consolidated Power Projects Office Halifax Street, Adelaide Date of Workshop: 28 th 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. FRM-A005 Page 1 of 2 Printed: 5-Sep-14 Ver 30 Jan ARTC RA Report Docx 10:58 AM

5 Consolidated Power Projects 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: 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: 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. FRM-A005 Page 2 of 2 Printed: 5-Sep-14 Ver 30 Jan ARTC RA Report Docx 10:58 AM

6 CONTEXT SETTING ARTC Risk Assessment - 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 ing 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. Stakeholders CPP, 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 Constraints OHL easement constraint. Constraint Environmental 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 V doc', Jacobs design endorsement letter 13. Other clarifying commentary None ARTC_SFAIRP_RA

7 Broken Hill Solar Plant Connection Rail Crossing - Engineering Waiver RA - 28/08/ Risk No Risk Category: 1. Safety 2. Assets 3. Financial 4. Environment 5. Regulatory 6. Reputation Safety 1. RISK IDENTIFICATION Hazard or Caused by scenario or circumstance If failure of pole fouls the track Pole failure under excessive load or material degradation. 1.3 Leading to an Most Likely Damage to rail Worst Case Derailment 2.0 Existing Control Pole design places 26 metre tall poles at least 50 metres from track 3.0 Proposed Additional Control BENEFIT 2. ANALYSIS AND EVALUATION 2.1 Responsible Party / Comments 3. PROPOSED ADDITIONAL RISK TREATMENT 3.01 CPP - Brad Furness 3.2 COST SFAIRP TEST 3.3 Decision 3.4 Responsible Party 3.5 By when 2.2 Current consequence Not Significant 2.3 Current likelihood Rare 2.4 Current risk level LOW (1D) 4. RESCORE TO REFLECT SFAIRP OUTCOMES 4.0 consequence 4.1 likelihood 4.2 risk level 5. VALIDATION AND CLARIFICATION Has this Comments / clarification workshop adequately addressed this risk? 5.1 Do the decisions make sense? 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. 1.0 Risk No Risk Category: 1. Safety 2. Assets 3. Financial 4. Environment 5. Regulatory 6. Reputation 2 Safety 1. RISK IDENTIFICATION 2. ANALYSIS AND EVALUATION 5. VALIDATION AND CLARIFICATION Current Current Current risk Caused by Leading to an Existing Control Responsible Party / Comments consequence likelihood level Comments / clarification 1.1 Hazard or scenario or circumstance Conductor falling across track Structure failure or broken conductor Most Likely Halt to train services/train delays Worst Case Damage to passing train, potential injury to passengers. ARTC track circuiting arrangments. AGL line protection and monitoring systems. AGL line maintenance regimes 3.0 Proposed Additional Control Administrative ARTC - Gary Templeton Confirm AGL AGL 3.1 BENEFIT 3.2 COST 3.3 Decision 3.4 Responsible Party 3.5 By when Not Significant Unlikely LOW (1D) 3. PROPOSED ADDITIONAL RISK TREATMENT 4. RESCORE TO REFLECT SFAIRP OUTCOMES 3.01 SFAIRP TEST 4.0 consequence 4.1 likelihood 4.2 risk level 5.0 Has this workshop adequately addressed this risk? 5.1 Do the decisions make sense? 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). Major Rare #REF! Pg 1 of 3 ARTC_SFAIRP_RA

8 1.0 Risk No Risk Category: 1. Safety 2. Assets 3. Financial 4. Environment 5. Regulatory 6. Reputation 1. RISK IDENTIFICATION 2. ANALYSIS AND EVALUATION 5. VALIDATION AND CLARIFICATION Current Current Current risk Caused by Leading to an Existing Control Responsible Party / Comments consequence likelihood level Comments / clarification 1.1 Hazard or scenario or circumstance Most Likely Worst Case ARTC track circuiting arrangments. AGL line protection and monitoring systems. AGL line maintenance regimes Administrative ARTC - Gary Templeton Confirm AGL AGL Not Significant Rare LOW (1E) 5.0 Has this workshop adequately addressed this risk? ARTC using Transport for NSW standard - EP SP. No one in the workshop is aware of any pole failures. 3 Safety Failure of Pole Complying with PYSO2 Halt to train services/train delays Damage to passing train, potential injury to passengers. 3.0 Proposed Additional Control 3. PROPOSED ADDITIONAL RISK TREATMENT 4. RESCORE TO REFLECT SFAIRP OUTCOMES BENEFIT 3.2 COST SFAIRP TEST 3.3 Decision 3.4 Responsible Party 3.5 By when 4.0 consequence 4.1 likelihood 4.2 risk level 5.1 Do the decisions make sense? #REF! 1.0 Risk No Risk Category: 1. Safety 2. Assets 3. Financial 4. Environment 5. Regulatory 6. Reputation 1. RISK IDENTIFICATION 2. ANALYSIS AND EVALUATION 5. VALIDATION AND CLARIFICATION Current Current Current risk Caused by Leading to an Existing Control Responsible Party / Comments consequence likelihood level Comments / clarification 1.1 Hazard or scenario or circumstance Most Likely Worst Case ARTC track circuiting arrangments. AGL line protection and monitoring systems. AGL line maintenance regimes Administrative ARTC - Gary Templeton Confirm AGL AGL Not Significant Unlikely LOW (1D) 5.0 Has this workshop adequately addressed this risk? AS/NZS 7000: 2010 design for structures is based on reliability (risk of failure) 4 Safety Failure of Pole Complying with AS/NZS 7000: 2010 Halt to train services/train delays Damage to passing train, potential injury to passengers. 3.0 Proposed Additional Control 3. PROPOSED ADDITIONAL RISK TREATMENT 4. RESCORE TO REFLECT SFAIRP OUTCOMES BENEFIT 3.2 COST SFAIRP TEST 3.3 Decision 3.4 Responsible Party 3.5 By when 4.0 consequence 4.1 likelihood 4.2 risk level 5.1 Do the decisions make sense? #REF! Pg 2 of 3 ARTC_SFAIRP_RA

9 1.0 Risk No Risk Category: 1. Safety 2. Assets 3. Financial 4. Environment 5. Regulatory 6. Reputation 1. RISK IDENTIFICATION 2. ANALYSIS AND EVALUATION 5. VALIDATION AND CLARIFICATION Current Current Current risk Caused by Leading to an Existing Control Responsible Party / Comments consequence likelihood level Comments / clarification 1.1 Hazard or scenario or circumstance Most Likely Worst Case in accordance with PYS02 CPP - Brad Furness Not Significant Unlikely LOW (1D) 5.0 Has this workshop adequately addressed this risk? Track clearance provided shall satisfy the requirements of PYS02. 5 Safety Conductor clearance infringement over track Structure deflection due to broken conductor in adjacent spans Halt to train services/train delays Damage to passing train, potential injury to passengers. 3.0 Proposed Additional Control 3. PROPOSED ADDITIONAL RISK TREATMENT 4. RESCORE TO REFLECT SFAIRP OUTCOMES BENEFIT 3.2 COST SFAIRP TEST 3.3 Decision 3.4 Responsible Party 3.5 By when 4.0 consequence 4.1 likelihood 4.2 risk level 5.1 Do the decisions make sense? Pg 3 of 3 ARTC_SFAIRP_RA

10 CONSOLIDATED POWER PROJECTS AUSTRALIA PTY LTD Adelaide Sydney Melbourne Head Office: 205 Halifax Street ADELAIDE SA 5000 ABN: Telephone: (08) Facsimile: (08) Web: MEMORANDUM To: Peter Faggion (Jacobs) Date: 07/08/14 From: Brad Furness Project No: 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) in PYS 02 should be updated to AS/NZS 7000: 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) 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: (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 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 Failure Containment Loads F b. A summary of the requirements is: The ultimate capacity of the structure shall not be overloaded for Failure Containment Loads FRM-A005 Page 1 of 2 Printed: 7-Aug-14 Ver 30 Jan ARTC PYS02 Updates V Docx 2:40 PM

11 Consolidated Power Projects Memorandum (continued) 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 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 5 0 C to 15 0 C). 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. FRM-A005 Page 2 of 2 Printed: 7-Aug-14 Ver 30 Jan ARTC PYS02 Updates V Docx 2:40 PM

12 Jacobs Group (Australia) Pty Limited Level 5, 33 King William Street Adelaide SA 5000 Australia PO Box 8291 Station Arcade SA 5000 Australia T F Adam Mackett AGL Energy Ltd L22, 101 Miller Street North Sydney August 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) should be replaced with AS/NZS 7000: 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/NZS 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: M: William.Battle@jacobs.com PE, NCEES, BE Electrical, MIEAust CPEng Jacobs Group (Australia) Pty Limited ABN Jacobs is a trademark of Jacobs Engineering Group Inc. Filename: AGL Broken Hill OHL OLX Endorsement 1