17/09/2014 - ARTC - Extranet Waivers/EW_TC... · There is a proposed 22kV double circuit over-head...
Transcript of 17/09/2014 - ARTC - Extranet Waivers/EW_TC... · There is a proposed 22kV double circuit over-head...
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
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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.
1.01Risk 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
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
Most Likely (Credible) Outcome
Worst Case (Credible) Outcome
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
decisions make sense?
3. PROPOSED ADDITIONAL RISK TREATMENT 4. RESCORE TO REFLECT SFAIRP OUTCOMES
3.0 Proposed Additional Control
3.01Control type
SFAIRP TEST4.0
Revised consequence
4.1Revised likelihood
4.2Revised risk
level
Major Rare #REF!
AGL
Pg 1 of 3 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
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
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
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
AGL
2.1Responsible Party / Comments
Complying with PYSO2
Most Likely (Credible) Outcome
Worst Case (Credible) Outcome
Halt to train services/train delays
Damage to passing train, potential injury to passengers.
1. RISK IDENTIFICATION 2. ANALYSIS AND EVALUATION 5. VALIDATION AND CLARIFICATION1.3
Leading to an Outcome
ARTC - Gary Templeton Confirm
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
decisions make sense?
3. PROPOSED ADDITIONAL RISK TREATMENT 4. RESCORE TO REFLECT SFAIRP OUTCOMES
3.0 Proposed Additional Control
3.01Control type
SFAIRP TEST4.0
Revised consequence
4.1Revised likelihood
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
2.1Responsible Party / Comments
4 Safety Failure of PoleComplying with AS/NZS 7000: 2010
Most Likely (Credible) Outcome
Worst Case (Credible) Outcome
ARTC - Gary Templeton Confirm
Halt to train services/train delays
Not Significant Unlikely LOW (1D)
AS/NZS 7000: 2010 design for structures is based on reliability (risk of failure)AGL
4.1Revised likelihood
4.2Revised risk
level
5.1Do the
decisions make sense?
3. PROPOSED ADDITIONAL RISK TREATMENT 4. RESCORE TO REFLECT SFAIRP OUTCOMES
3.0 Proposed Additional Control
3.01Control type
SFAIRP TEST4.0
Revised consequence
#REF!
Damage to passing train, potential injury to passengers.
Pg 2 of 3 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
Design in accordance with PYS02Engineering/
DesignYes
3.1 BENEFIT
3.2COST
3.3Decision
3.4Responsible
Party
3.5By when
Yes
1. RISK IDENTIFICATION 2. ANALYSIS AND EVALUATION 5. VALIDATION AND CLARIFICATION1.3
Leading to an Outcome2.1
Responsible Party / Comments
5 Safety
Conductor clearance infringement over track
Structure deflection due to broken conductor in adjacent spans
Most Likely (Credible) Outcome
Worst Case (Credible) Outcome
CPP - Brad Furness
Halt to train services/train delays
Not Significant Unlikely LOW (1D)
Track clearance provided shall satisfy the requirements of PYS02.
4.1Revised likelihood
4.2Revised risk
level
5.1Do the
decisions make sense?
3. PROPOSED ADDITIONAL RISK TREATMENT 4. RESCORE TO REFLECT SFAIRP OUTCOMES
3.0 Proposed Additional Control
3.01Control type
SFAIRP TEST4.0
Revised consequence
Damage to passing train, potential injury to passengers.
Pg 3 of 3 ARTC_SFAIRP_RA
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)
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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