Attachment 11.8 Jacobs: Recommended bushfire risk reduction strategies for SA Power Networks October 2014 Recommended Bushfire Risk Reduction Strategies FOR SA POWER NETWORKS Final Report| October 2014 Recommended Bushfire Risk Reduction Strategies Recommended Bushfire Risk Reduction Strategies Document title: Recommended Bushfire Risk Reduction Strategies Revision: Final V7.0 Date: 28 October 2014 Prepared by: Phillip Webb Approved by: Greg Whicker File name: Bushfire Risk Reduction Strategies_Final Report_V7_281014 Jacobs Group (Australia) Pty Limited ABN 37 001 024 095 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 COPYRIGHT: The concepts and information contained in this document are the property of Jacobs Group (Australia) Pty Limited. Use or copying of this document in whole or in part without the written permission of Jacobs constitutes an infringement of copyright. Recommended Bushfire Risk Reduction Strategies Contents 1. Executive Summary 1 2. Introduction 3 3. Fire Start History 4 3.1. 3.2. 3.3. 4 5 5 Fire Start Statistics - Summary Fire Start Reduction Calculations State-specific issues 4. Summary Analysis of Bushfire Risk Mitigation Strategies 6 5. Detailed Analysis of Bushfire Risk Mitigation Strategies 10 5.1. 33kV, 19kV and 11kV SCADA Reclosers 11 5.1.1. 5.1.2. 5.1.3. 5.1.4. 5.1.5. 5.1.6. 5.1.7. Description Background Existing units Modern Units Industry Practice Costs Discussion and implementation strategy 11 11 11 12 13 13 13 5.2. Undergrounding or insulating LV, 11kV and 33kV Lines 15 5.2.1. 5.2.2. 5.2.3. 5.2.4. 5.2.5. Description Background Industry Practice Route Lengths and Costs Discussion and implementation strategy 15 15 15 16 16 5.3. Increased Frequency of Asset Inspections 18 5.3.1. 5.3.2. 5.3.3. 5.3.4. 5.3.5. 5.3.6. Description Background Industry Practice Effectiveness Costs Discussion and implementation strategy 18 18 19 19 20 20 5.4. Thermographic Inspections in H/MBFRA 21 5.4.1. 5.4.2. 5.4.3. 5.4.4. 5.4.5. Description Background Industry Practice Costs Discussion and implementation strategy 21 21 22 22 22 5.5. Install Surge Arrestors 23 5.5.1. 5.5.2. 5.5.3. 5.5.4. 5.5.5. Description Background Industry Practice Costs Discussion and implementation strategy 23 23 23 23 24 5.6. Ground Fault Neutralising Technology 25 i Recommended Bushfire Risk Reduction Strategies 6. 5.6.1. 5.6.2. 5.6.3. 5.6.4. 5.6.5. 5.6.6. Description Background Industry Practice Efficiency Typical Costs Discussion and Implementation Strategy 25 25 25 26 26 27 5.7. Re-construct Metered Mains 28 5.7.1. 5.7.2. 5.7.3. 5.7.4. Description Background Industry Practice Implementation Strategy 28 28 29 29 5.8. Backup Protection 31 5.8.1. 5.8.2. 5.8.3. 5.8.4. Requirement Background Industry Practice Implementation Strategy 31 31 32 32 Recommended Strategies for AER Submission 33 6.1. 6.2. Good Industry Practice Detailed Strategy Analyses - Summary 33 34 6.2.1. 6.2.2. 6.2.3. 6.2.4. 6.2.5. 6.2.6. 6.2.7. 6.2.8. 6.2.9. General SCADA reclosers for 33kV, 19kV and 11kV New LV, 11kV and 33kV construction Asset inspection frequency Thermographic inspections Surge arrestors Ground fault neutralising technology Re-construct metered mains Backup protection 34 34 34 35 35 35 35 36 36 6.3. Recommended Strategies and Estimated Costs 37 7. References 38 8. Appendix 1: SA Power Networks fire report - Rod Air Gaps 39 9. Appendix 2: SA Power Networks fire report - hot joint 40 10. Attachment 1: Summary CV Information 42 ii Recommended Bushfire Risk Reduction Strategies 1. Executive Summary Jacobs1 was engaged by SA Power Networks to review their bushfire risk management practices and assist with the development of strategic options for possible inclusion in SA Power Networks’ AER reset submission. The scope of work included a review of: - SA Power Networks’ current practices and procedures for bushfire risk management; - SA Power Networks’ fire start history to establish root causes; - Current research on bushfire risk management practices for electricity distributors; - The relevant findings of the Victorian Bushfires Royal Commission and the subsequent Powerline Bushfire Safety Taskforce; - Bushfire Risk Management initiatives by Distribution Network Service Providers in other Australian states. Jacobs considers it prudent for SA Power Networks to implement additional risk mitigation strategies to ensure that it complies not only with regulations, but also with good industry practice that has evolved in recent years following extreme events interstate including: - Improved asset and risk management processes; - Upgrading of obsolete equipment to modern construction; - The installation of modern remote controlled technology for control, fault detection & protection; - Efficient and effective asset inspection and monitoring procedures that trigger appropriate and timely maintenance regimes; and - Trialling of new technology. Jacobs was requested to apply the network management experience and engineering judgement of its project team to recommend a practical, cost-effective package of risk mitigation strategies that would allow SA Power Networks to operate in a manner consistent with current “good industry practice”. The eight recommended strategies described in Section 6 of this report have been chosen to target the issues and areas of highest fire start risk, accommodate SA Power Network’s capability to execute, and provide optimum fire risk mitigation benefits at a modest cost. Table 1 summarises these recommended strategies and costs. SA Power Networks should apply risk management principles to assess the probability and consequence of fire starts for each of its feeders in high bushfire risk areas. These risk assessments will assist selection of the appropriate strategy and priority for each feeder within a staged work program. 1 Jacobs Engineering Group acquired Sinclair Knight Merz in December 2013. 1 Recommended Bushfire Risk Reduction Strategies Table 1: Recommended Bushfire Risk Reduction Strategies and Estimated Costs2 Strategy No. 1 Section and content 2015/16 2016/17 2017/18 2018/19 2019/20 5.1 Replace 33kV, 19kV and 11kV reclosers with SCADA controlled modern units $3.6m $3.6m $3.6m $3.6m $3.6m $18.0m 2 5.2 Undergrounding or insulating LV, 11kV and 33kV lines $5.7m $5.9m $3.8m $6.3m $4.9m $26.6m 3 5.3 Increase the frequency of asset inspections $2.3m $2.6m $2.7m $2.7m $2.7m $13.0m 4 5.4 Extend and increase the frequency of thermographic asset inspections $0.5m $0.5m $0.5m $0.5m $0.5m $2.5m 5 5.5 Replace rod air gaps and current limiting arcing horns with Surge Arrestors $2.4m $2.4m $2.4m $2.4m $2.4m $12.0m 6 5.6 Undertake field simulation, testing and trial installation of Ground Fault Neutralisation Technology $1.0m $4.0m $5.0m $2.0m $12.0m 7 5.7 Reconstruct metered mains $4.1m $8.2m $8.2m $8.2m $4.1m $32.8 8 5.8 Backup protection $2.9m $3.0m $3.4m $3.6m $5.6m $18.5m $21.5m $27.2m $28.6m $32.3m $25.8m $135.6m Totals 2 Total All costs are in June 2015 dollars 2 Recommended Bushfire Risk Reduction Strategies 2. Introduction Jacobs was engaged by SA Power Networks to review their bushfire risk management practices and assist with the development of strategic options for possible inclusion in SA Power Networks’ AER reset submission for 2015-2020. The review was conducted by senior Jacobs personnel Phillip Webb, Terry Krieg and Greg Whicker. Summary CV information is included as Attachment 1. The scope of work included: Consult with key SA Power Networks managers to discuss the effectiveness of current bushfire risk management strategies and those currently being considered; Carry out a detailed review of SA Power Networks’ fire start history to establish root causes (summarised in Section 3 of this report); Carry out a review of: - SA Power Networks’ current practices and procedures for bushfire risk management; - Current research on bushfire risk management practices for electricity distributors; - The relevant findings of the Victorian Bushfires Royal Commission (VBRC) and the subsequent Powerline Bushfire Safety Taskforce (PLBSTF); - The Bushfire Risk Management initiatives by Distribution Network Service Providers (DNSPs) in other Australian states. Carry out a preliminary assessment of potential risk mitigation strategies considering benefits, limitations and their effectiveness in reducing the number of fire starts (summarised in Section 4 of this report). Identify those strategies which are either ‘current practice’, ‘not applicable to SA Power Networks’, or of ‘low benefit’ to exclude these strategies from detailed analysis; Carry out a detailed analysis of those ‘included strategies’ providing an approximate cost estimate for each strategy (summarised in Section 5 of this report); and Use the network experience and engineering judgement of Jacobs’ project team to recommend a practical, cost-effective package of risk mitigation strategies that would allow SA Power Networks to operate in a manner consistent with current ‘good industry practice’. These strategies, which may be presented to the AER as part of SA Power Networks’ Reset submission, are discussed in Section 6 of this report. 3 Recommended Bushfire Risk Reduction Strategies 3. Fire Start History This Section summarises the findings from a detailed review of SA Power Networks’ fire start history to establish root causes. 3.1. Fire Start Statistics - Summary SA Power Networks records comprehensive data on fire starts that have been associated with its network assets. It classifies areas of the State into one of three bushfire risk categories: High Bushfire Risk Area (HBFRA), Medium Bushfire Risk Area (MBFRA) and Non-Bushfire Risk Area (NBFRA). The MBFRA is an area where a fire could start and readily escape to an unrestricted area of flammable material causing Moderate Consequences3. The relevant parts of the state are shown in the maps in Schedule 4 of the Electricity (Principles of Vegetation Clearance) Regulations 2011. The HBFRA is an area where a fire could start and readily escape into an unrestricted area of flammable material causing Major to Catastrophic Consequences4, broadly classified as areas which receive 600mm or more rainfall. The BFRA as defined in the Electricity (Principles of Vegetation Clearance) Regulations 1996 Schedule 3 is the combination of the MBFRA and the HBFRA. The Non BFRA is also as defined in the Regulations. Jacobs carried out a detailed assessment of SA Power Networks’ fire start history to determine root causes and number of fire starts by voltage and bushfire risk area. Table 2 shows the number of fire starts per 1,000kms across all voltages and all bushfire risk areas for the period 1 January, 2008 to 31 December, 2012. The average number of fire starts over this period is 67 per annum, of which 53 per annum are in the HBFRA and MBFRA. As the length of line influences the potential for a fire start, the number of fire starts per 1,000kms was calculated to determine which voltage was the highest fire risk. Table 2: Number of Fire Starts per 1,000 kms Voltage Bushfire Risk Area HBFRA MBFRA NBFRA LV 7.6 &11kV 33kV 19kV 66kV 9 4 2 11 8 10 24 13 5 2 1 0 8 1 0 This table shows that most fire starts per 1,000kms in both the MBFRA and HBFRA are from the 33kV Network. 3 4 Adapted from AS/NZS ISO 31000:2009 Risk Management – Principles and Guidelines Ibid 4 Recommended Bushfire Risk Reduction Strategies 3.2. Fire Start Reduction Calculations The approach adopted by Jacobs in estimating the potential fire start reduction for a particular risk mitigation strategy was to pro-rata the reduction on the basis of ‘fire starts per route km’ for which the strategy is applied. A moderate efficiency factor between 1 and 2 was also applied, recognising that each strategy would be targeted to be applied to the locations and assets with the highest risk and highest fire start potential first. In some cases, however, an efficiency factor of less than 1 was applied because there is less than a 1 to 1 benefit from implementation. For example, increasing the frequency of inspections across all fire risk areas will improve the detection of fire start defects, but will not eliminate them. 3.3. State-specific issues South Australia experienced extreme bushfires on 16 February 1983 with 28 lives lost. That, and other factors, triggered the evolution of comprehensive bushfire risk management processes within SA Power Networks (previously known as ETSA). During the past decade, Jacobs has monitored SA Power Networks’ annual Fire Danger Level Exercise and the refinement of its Bushfire Risk Management system. These processes are now considered mature, comprehensive, appropriately documented and well managed. SA Power Networks’ construction standards vary from those interstate in several ways that assist with reducing bushfire starts: (i) (ii) (iii) Concrete and steel poles (Stobie poles) are used in SA, whereas wooden poles are generally used interstate. Stobie poles are of consistent mechanical strength, are not combustible and are not prone to termite attack. This results in longer life and a lower likelihood of failure in high winds; Steel cross arms are used in SA for all voltages in bushfire risk areas compared to a wider use of timber interstate. Unlike wooden cross arms, steel cross arms are not combustible and do not catch fire during events such as flashover (caused by conductors on cross arms) or lightning surges; In many locations, SA Power Networks uses a common multiple earthed neutral (CMEN) arrangement that provides a low impedance path for fault current back to the source zone substation. CMEN, coupled with steel cross arms and steel poles, provides low impedance for earth fault currents resulting in generally fast protection operation and clearance. However, even a single fire start on an extreme fire risk day in a location with hilly terrain and large quantities of dry grass and/or forest fuels could result in another catastrophic bushfire in SA. The high population densities within some areas of the Mount Lofty Ranges, in particular, significantly increase the consequences of a fire start. 5 Recommended Bushfire Risk Reduction Strategies 4. Summary Analysis of Bushfire Risk Mitigation Strategies This Section summarises the findings from a preliminary assessment of potential risk mitigation strategies considering benefits, limitations and their effectiveness in reducing the number of fire starts. The following table lists risk mitigation strategies that have been sourced by Jacobs from: - The current bushfire mitigation practices of Australian DNSPs; The outcomes of the VBRC into Victoria’s Black Saturday bushfires; and The subsequent report of the PLBSTF. These strategies have been categorised into three main areas: - Those that target the direct reduction of fire starts, such as insulated conductors and undergrounding; Those that improve the efficiency of bushfire risk management, such as fire risk consequence modelling; and Those that improve safety through flexible, remotely controlled equipment, such as modern circuit reclosing devices with supervisory control and data acquisition (SCADA). Some strategies can provide benefits in more than one category. The final column in the following table indicates whether a particular strategy is included in the detailed analysis in Section 5 of this report, and provides the reason for its exclusion (if applicable). Strategies that, at best, could only affect 10% or less of the annual fire starts have been excluded due to their low impact on the fire start risk and the expectation that other recommended strategies are likely to resolve that specific fire start risk. For example, ‘bird covers on bushings’ is effectively addressed when bare conductors are replaced with insulated or underground conductors. Table 3: Summary of Preliminary Analysis of Strategies Strategy Description Details Source/Basis Included/Excluded Main Category/ Reason Replace 33kV, 11kV and Replace aging hydraulic reclosers PLBSTF, Essential Included 19kV reclosers with which have limited setting capability Energy, SP AusNet, SCADA controlled modern with SCADA controlled units with Western Power Efficiency/Safety units flexible settings Underground or insulated Installation of underground or PLBSTF, Western Included HV in HBFRA insulated conductor in targeted areas Power, SP AusNet Insulated conductor eg Hendrix Essential Energy Fire Start Reduction conductor (3 insulated cables spaced apart and supported with a catenary/ground wire). 6 Recommended Bushfire Risk Reduction Strategies Strategy Description Details Source/Basis Included/Excluded Main Category/ Reason Underground or insulated Installation of underground or LV in HBFRA insulated conductor eg ABC. PLBSTF Included Fire Start Reduction LV private line A distributor-funded incentive to Essential Energy Not specifically included undergrounding incentive underground Private LV lines that – See similar issue scheme have defects, vegetation management identified as “Metered or end-of- life issues Mains” Targeted asset Outcomes of the application of the fire SP AusNet, Not specifically included replacement based on fire consequence model to a network will Essential Energy – current practice consequence model be to target bushfire risk mitigation Efficiency projects for specific assets identified as presenting extreme risk. Field work standards Development and monitoring of field All DNSPs work construction and operational Not specifically included – current practice activities and methods to ensure Distribution entity staff and contractors do not create fire start risks. Increase the frequency of Increase the frequency and extent of asset inspections asset inspections. PLBSTF, All DNSPs Included Fire Start Reduction Extend and increase the Extend the practice of thermal frequency of thermographic inspections asset inspections All DNSPs Included Fire Start Reduction 7 Recommended Bushfire Risk Reduction Strategies Replace rod air gaps and Installation of surge arrestors on pole Eastern States current limiting arcing top transformers is standard practice DNSPs horns with Surge Arrestors in Eastern state DNSPs. This is now Included Fire Start Reduction also standard practice for SA Power Not standard Networks, but there is a significant construction for high legacy of rod gaps and current limiting fire risk areas arcing horns. Undertake field simulation, Based on trial results, install GFN PLBSTF testing and trial installation technology in substations supplying Future projects subject to of Ground Fault high bushfire risk areas. results of trials and Neutralisation (GFN) Included on a trial basis. interstate utility feedback Technology Fire Start Reduction/Safety Reconstruct metered Mains Inspect to assess condition and SA Power Networks Included address issues - LV beyond metering Fire start reduction/safety point in rural areas. Backup protection Realign feeder protection to the All DNSPs Included requirements of the National Fire Start Reduction Electricity Rules Clearing of Hazardous Trees Change legislation to permit the clearing of hazardous trees. PLBSTF, SA Power Networks, Not specifically Included Low benefit SP AusNet, Essential Energy LIDAR Technology Vegetation management Investigate and develop the application of LIDAR technology towards vegetation identification and analysis in relation to bushfire risk. Ergon Manage vegetation by inspection and cutting as required by legislation All DNSPs Included in other parts of the Reset submission Efficiency Not specifically included – Existing practice 8 Recommended Bushfire Risk Reduction Strategies Fire consequence model development Industry Research Network performance and Planning Maintenance Program Reporting and investigation of fire starts Analysis of information from other sources Distribution Businesses Develop fire consequence heat maps based on recognized fire propagation models and apply this to network assets in high bushfire risk areas. These simulations are able to apply fire footprints initiated at network assets and the consequential losses including dwellings. This information provides a risk/location profile that leads to targeted bushfire risk mitigation projects. Essential Energy, SP AusNet Monitor, evaluate and contribute towards academic and industry research into the management, prevention and mitigation of bushfires. All DNSPs Monitor the performance of feeders for reliability and fire starts and implement remediation work for poorly performing feeders especially in risk areas All DNSPs Targeted refurbishment programs for specific assets that have end of life failures or type defects All DNSPs Comprehensive and detailed monitoring and reporting of fire starts. Fire start investigation and analysis provide an opportunity to review performance and adopt mitigating strategies based on historical events and real life experience. All DNSPs Continuous monitoring of fire start experiences and industry investigations or public reports. Working with other distributors to share information and experience in regard to fire starts where the opportunity exists. All DNSPs Western Power developing its own model but similar basis as per Eastern states. Included, but SA Power Networks has a project in progress Efficiency Not specifically included – current practice Not specifically included – current practice Not specifically included – current practice Not specifically included – current practice Not specifically included – current practice 9 Recommended Bushfire Risk Reduction Strategies 5. Detailed Analysis of Bushfire Risk Mitigation Strategies Jacobs carried out a detailed assessment of each of the ‘Included’ strategies listed in Table 3. Some key strategies, particularly ‘fire consequence model development’, are already being progressed by SA Power Networks. This Section discusses the eight strategies subsequently ‘Recommended’ by Jacobs. These particular strategies and implementation options were selected to target the issues and areas of highest fire start risk, accommodate SA Power Network’s capability to execute, and provide optimum fire risk mitigation benefits at a modest cost. Note that: - The underpinning network data and fire statistics have been provided by SA Power Networks; and The key costs have been sourced from SA Power Networks and the PLBSTF report. 10 Recommended Bushfire Risk Reduction Strategies 5.1. 33kV, 19kV and 11kV SCADA Reclosers 5.1.1. Description SA Power Networks and other Australian DNSPs have many ageing HV automatic circuit reclosers in service that should be replaced with modern SCADA controlled units to reduce the fire start risk and improve safety for the community and power line workers. 5.1.2. Background 33kV, 19kV &11kV reclosers are self-contained circuit breakers with inbuilt fault detection mechanisms and control systems to allow reclosing. The reclosing function restores electricity following a transient fault. If the fault is permanent, the device remains open or “locks out” until manually reset. These units are constructed to be pole mounted and are usually installed on overhead line pole structures or on stub-poles in substations. The ageing types predominantly use hydraulic mechanisms for fault detection and operation. 5.1.3. Existing units The limitations of existing units are mainly associated with inflexible protection and control settings and an inability to remotely monitor or control their operation. Protection setting flexibility The fault detection settings, namely duration and the trip close sequences and timings, are limited and fixed once set. Changes to these parameters require the unit to be returned to the workshop and internally modified. The reclose time can potentially reduce the risk of fire start, as it has been found that longer reclose times increase the probability of a fault-caused fire start (Marxsen et al 2012). Remote Control and Monitoring These units are unable to be remotely controlled or monitored. They are unable to be remotely switched off during extreme fire danger events and require either: - Upstream devices to be switched off (involving more network & customers than required to be disconnected); or Field staff to attend to disable reclosing or to disconnect or re-connect prior to or following a bushfire event. Sending staff into areas where the fire danger conditions are extreme would greatly risk their personal safety. In evidence given at the VBRC5, it was agreed that the probability of a fire starting from a downed conductor increased significantly if the recloser operated slowly and operated a number of times. Disabling the reclose function and setting the recloser to clear faults as quickly as possible, significantly reduces the risk of a fire starting from a line fault. Tests by Marxsen et al (2012) confirmed this for a “worst case fire condition”. 5 Transcript of Victorian Bushfires Royal Commission, Tuesday 17 November 2009, pp 11103-11106 11 Recommended Bushfire Risk Reduction Strategies Weather conditions change dramatically on extreme fire weather days. The following chart shows the turbulent and sudden increases in mean wind speeds and wind gusts at Williamtown Automatic Weather Station on 13/10/13, when a fire affecting 200 homes started from electricity assets. Such weather charts are typical of extreme fire weather days. Williamtown Fire Start time 100 80 60 40 20 0 10:30 11:30 12:30 13:30 14:30 15:30 16:30 17:30 18:30 19:30 20:30 21:30 22:30 23:30 00:30 01:30 02:30 03:30 04:30 05:30 06:30 07:30 08:30 09:00 10:00 10:20 11:00 11:30 12:30 13:30 14:30 15:00 16:00 17:00 17:30 18:30 19:30 20:30 21:00 22:00 22:41 22:47 23:00 23:26 00:00 00:23 00:33 01:00 01:39 01:58 02:10 02:33 02:47 03:30 04:30 05:30 06:30 07:30 08:30 09:30 10:30 11:30 12:30 13:30 14:30 15:30 16:30 17:30 18:30 19:30 20:30 21:30 22:30 23:00 23:51 00:30 01:30 02:07 02:49 03:30 04:30 05:30 06:30 07:30 08:30 09:30 Wind Spd (km/h) 12/10/2013 13/10/2013 14/10/2013 Wind Gust (km/h) 15/10/2013 Placing a recloser to fast acting, single shot fault clearing mode reduces fire start risk and SCADA control avoids the deployment of line crews which (a) takes too long and (b) in extreme fire danger conditions is a safety risk. Many of SAPN’s reclosers are not remotely controllable, especially on SWER, as per the table below: Table 4: Reclosers not on SCADA 5.1.4. Area 33kV 11/7.6kV 19kV TOTAL HBFRA 13 124 69 206 MBFRA 27 87 367 481 TOTAL 40 211 436 687 Modern Units Modern reclosers have a wide range of protection settings that can be programmed and changed in-situ. SCADA control enables remote changing of protection and control functions eg disabling or enabling reclose, opening, closing and status and load monitoring. SCADA control also provides the capability for SA Power Networks to remotely exercise their statutory ability to disconnect under specific extreme conditions in order to prevent fire starts from network assets. Modern reclosers are generally more sensitive than the older types at fault detection and can also trip at higher speeds. The range of settings available is more comprehensive and can be adjusted for optimum protection 12 Recommended Bushfire Risk Reduction Strategies performance given the specific network characteristics. The addition of SCADA control provides the same range of remote control and monitoring functions that have previously only been available at zone and terminal substations. Holmes (2011, 15 September) reported on the recent manufacture of a “…new ACR to dramatically reduce the injected arc energy under SWER fault conditions, to levels that can significantly reduce the probability of bushfire ignition even under high risk conditions…”. Transmission and Distribution magazine reported in their February/March 2012 edition that after successful trials “…projects are in place to install large quantities of Smart SWER Reclosers in bushfire prone areas…(in Victoria)” (T&D p. 13) 5.1.5. Industry Practice Most Australian DNSPs are now installing modern SCADA controlled reclosers for improved protection capability, remote control and setting of the reclose function and trip sequences. Recommendation 32 of the VBRC requires that the reclose function on distribution power line reclosers is disabled in high-risk areas on total fire ban days. The practice of disabling reclose on high fire risk days6 has been standard practice in SA Power Networks for many years. In many cases, this has been achieved manually by site attendance when time and resources permit. 5.1.6. Costs The approximate cost of replacing an ageing recloser with a modern unit is about $120,000, which includes SCADA and the associated communications equipment. 5.1.7. Discussion and implementation strategy During the years 2008 to 2012, over 50% of SA Power Networks’ fire starts occurred on 11kV and 7.6kV networks. The 33kV network has a lower number of fire starts but has a higher rate of fire starts per 1,000 route kms. The implementation of Bushfire Risk Reduction Strategy (BRRS) no. 1 – the recloser replacement program – is impacted by BRRS no. 8 – Back-up Protection. It is estimated that implementing this latter strategy will account for the replacement of 55 of the 206 non-SCADA reclosers in the HBFRA. Hence, the remaining 151 reclosers will be replaced as part of BRRS no. 1. SA Power Networks advises that there is capacity to replace around 40 reclosers per annum, which will be comprised of 30 per annum for strategy no. 1 and 11 per annum for strategy no. 8, and hence the conversion of reclosers to SCADA control in the HBFRA is expected to be completed within the 2015-2020 five year period. Priority order should be replacing 33kV and 11kV reclosers, followed by 19kV reclosers. Once the HBFRA is completed, consideration should be given to extending the programme to the MBFRA. The priority order should be based on risk management principles and should consider: 6 Total Fire Ban days with mean wind speeds forecast to be at least 45km/h 13 Recommended Bushfire Risk Reduction Strategies 1) Feeder reliability history; 2) Fire start history; 3) Length of line protected by the recloser; 4) Number of Total Fire Ban (TOBAN) days; 5) Feeder voltage; and 6) The potential losses from a bushfire taking into account population, terrain, fuel loads and fuel types. Table 5: Proposed implementation strategy costing for 33kV, 19kV & 11kV reclosers 2015/16 Replace 30 per annum nonSCADA 33kV, 19kV, 7.6kV & 11kV reclosers with SCADA Controlled Reclosers $3.6m 2016/17 $3.6m 2017/18 $3.6m 2018/19 $3.6m 2019/20 $3.6m 14 Recommended Bushfire Risk Reduction Strategies 5.2. Undergrounding or insulating LV, 11kV and 33kV Lines 5.2.1. Description Bare overhead conductor is the standard form of construction for high voltage distribution lines. However, as the line is bare, it is vulnerable to ‘environmental’ faults such as vegetation, animals and insulation pollution. When faults occur, a fire may start due to direct contact, arcing or from the by-products of flashover. Re-building lines underground provides significant benefits, including elimination of fire start risk, but at relatively high cost. A highly targeted program of undergrounding is typically implemented to reduce the risk of fire starts at a reasonable cost. Alternatively, bare conductors can be replaced with insulated conductors that reduce fire start risk at a lower cost to undergrounding. 5.2.2. Background The SA Power Networks distribution network comprises 66 kV and 33 kV sub transmission lines, three phase and single phase 11kV distribution lines, 19kV SWER lines and low voltage (LV) lines. As mentioned in Section 3.1, 33kV power lines start more fires per 1,000kms of line than all of the other voltages. Insulated conductor technology is an overhead construction but the conductors are insulated with a covering and supported in a bundle or spaced apart. There are a number of variants and the most popular are Aerial Bundled Conductor (ABC), Covered Conductor Thick (CCT) and Hendrix conductor. ABC is made up of tightly bundled insulated and screened conductors, while CCT is a conductor around which is applied a thick insulating material but without a screen. The Hendrix system is made up of 3 insulated conductors in a closed triangular/delta configuration, supported by a catenary wire. The Hendrix system appears to provide the most satisfactory alternative to large scale conversion of bare conductor to an insulated construction. By using a support wire under tension and with the phase conductors suspended below, the Hendrix system allows the construction of longer spans than ABC. Hendrix systems are not as aesthetically pleasing as undergrounding, but are generally lower in cost. Undergrounding of overhead 33kV and 11kV power lines also effectively eliminates bushfire start risk. Undergrounding avoids the costs that are still incurred to keep growing vegetation from rubbing against overhead insulated conductor. Also, feedback from customer surveys confirms that customers are often willing to pay for targeted undergrounding of powerlines when there are joint visual amenity and fire start risk reduction benefits. 5.2.3. Industry Practice Australian DNSPs are typically undergrounding in circumstances such as: New residential estates; Where there is a financial benefit to do so; Joint utility/local council funded undergrounding schemes; and Projects initiated by individuals or developers who contribute towards the costs. 15 Recommended Bushfire Risk Reduction Strategies Recommendation 27 of the VBRC related to the progressive replacement of distribution feeders with underground cable, ABC, or other technology that delivers greatly reduced bushfire risk. The PLBSTF recommended implementation of this recommendation by the targeted replacement of distribution power lines with underground or insulated overhead cable. 5.2.4. Route Lengths and Costs The following table identifies the route lengths of overhead conductors in the SA Power Networks distribution network and approximate costs of reconstruction of bare lines with alternative conductors. Table 6: Route Lengths and Costs for New 11 and 33kV Construction VOLTAGE HBFRA Route km MBFRA Route km 11kV 7079 5902 33kV 931 2575 CONSTRUCTION TYPE COSTS per route km7 Undergrounding $260k to $650k ABC/CCT $220k to $320k Hendrix $90k to $170k Average $120k 5.2.5. Discussion and implementation strategy Broad scale undergrounding of overhead HV lines is generally an unrealistic option due to the high cost. However targeted undergrounding to avoid vegetation clearance or to provide a robust all-weather supply to 8 Bushfire Safer Precincts (BSP) should be considered on a case-by-case basis. Insulated conductor is vulnerable to the effects of bushfires and hence undergrounding lines is preferred for supply to BSPs. However, should SA Power Networks consider broad scale conversion of bare lines in HBFRA in order to lower fire start risk, an insulated conductor system may prove more cost effective. A proposed implementation strategy for undergrounding lines to BSPs is shown in Table 7. Note that undergrounding of other parts of the network for aesthetic and fire start risk reduction reasons is included in other parts of SA Power Networks’ Reset Submission. 7 From PLBSTF Final Report 8 http://www.cfs.sa.gov.au/site/prepare_for_bushfire/know_your_area/bushfire_safer_places.jsp 16 Recommended Bushfire Risk Reduction Strategies The CFS has identified 65 BSPs in high bushfire risk areas. Jacobs recommends that SA Power Networks applies risk management principles to prioritise these sites. The proposed implementation strategy shown in Table 7 covers undergrounding of lines to 12 BSP sites over a 5 year period. Table 7: Proposed Implementation Strategy for 11kV and 33kV supply to BSPs 2015/16 Undergrounding of 11kV and 33kV to BSPs $5.7m 2016/17 $5.9m 2017/18 $3.8m 2018/19 $6.3m 2019/20 $4.9m 17 Recommended Bushfire Risk Reduction Strategies 5.3. Increased Frequency of Asset Inspections 5.3.1. Description In complying with the Electricity Act and Distribution License requirements, SA Power Networks submits a Safety, Reliability, Maintenance and Technical Management Plan (SRMTMP) annually to the State Government’s Office of the Technical Regulator (OTR). Periodic asset inspections are an integral part of the SRMTMP. 5.3.2. Background All Australian DNSPs engage qualified asset inspectors to undertake routine asset inspections using visual and various inspection equipment. Specific inspection procedures and training ensure a high quality of inspections. SA Power Networks’ asset inspection period varies from 5 years for high corrosion zones to 10 years for low corrosion zones. Whilst there is some HBFRA in high corrosion zones, the majority of H/MBFRA is located in low corrosion zones. The typical period for detailed asset inspections is therefore 10 years. To complement the inspection programme, a pre-bushfire season patrol is conducted for all assets in bushfire risk areas, with specific focus on fire start issues. Evidence shows that these patrols are effective at finding defects which develop after spring storms and vegetation which grows more rapidly than expected. Figure 1 – Photo taken during pre-bushfire season aerial patrol programme 18 Recommended Bushfire Risk Reduction Strategies 5.3.3. Industry Practice Typical inspection regimes across Australia are time based with historical inspection regimes as per the following table: Distributor Historical Overhead assets Inspection Frequency9 ActewAGL 4.5 – 5 years Endeavour Energy 4.5 years Jemena 5 years TransGrid 4 yearly Powercor 5 yearly SPI Ausnet 5 yearly Essential Energy 4 yearly The VBRC investigated the causes of the bushfire starts on 7 February 2009 in Victoria. Five of these bushfires were confirmed as having started from electricity assets. In July 2010 the VBRC released its findings, eight of which directly related to measures for preventing future bushfire starts from electricity assets. One of the recommendations was that, based on the evidence that had been presented, Victorian utilities should move from their existing 5 year inspection cycle to a 3 year inspection cycle. The Victorian Government then legislated this requirement. Jacobs suggests that the Victorian requirement establishes a new industry standard, taking into account historical inspection frequency. Jacobs recommends that SA Power Networks: - 5.3.4. Initially increases the frequency of asset inspections to a maximum of every 5 years for HBFRA and MBFRA; Assess whether a further increase in frequency of asset inspections (e.g. to 3 years) is warranted for these areas; Gradually increases the frequency of asset inspections for all other areas to 5 years; and Retains the annual pre-bushfire season patrols in their current form. Effectiveness Examination of fire start records indicate that many fire starts may be avoided over a 5 year period in H/MBFRA with highly effective asset inspections. 9 SKM survey of Australian Distribution Network Service Providers August 2013 19 Recommended Bushfire Risk Reduction Strategies 5.3.5. Costs The costs associated with inspections vary according to the geographic location (metropolitan compared to country), terrain, accessibility and type of construction. Also, the extent of asset condition detail recorded during the inspection determines the time taken and thus cost. Inspection costs can be in the order of $500 to $2,500 per route km depending on the density of assets along the route. A reasonable estimate for rural and country asset inspections is $500 per route km. 5.3.6. Discussion and implementation strategy A reasonable implementation strategy would be as follows: 1) Increase the frequency of asset inspections to a maximum of every 5 years for HBFRA and MBFRA; 2) Gradually increase the frequency of asset inspections to every 5 years for all other areas; 3) Assess whether a further increase in frequency of asset inspections (e.g. to 3 years) is warranted. The costing of this strategy is based on the difference in expenditure between the current regime and the proposed regime. Table 9: Proposed Implementation Strategy Costings for Increased Asset Inspections 2015/16 Increased inspections $2.3m 2016/17 $2.6m 2017/18 $2.7m 2018/19 $2.7m 2019/20 $2.7m 20 Recommended Bushfire Risk Reduction Strategies 5.4. Thermographic Inspections in H/MBFRA 5.4.1. Description Thermographic inspections of overhead powerlines can assist in the identification of potential conductor and joint faults. Figure 2 – typical record of a hot joint inspection Hot joints can arise in line conductors where a sleeve has been used to connect conductors, or in connections to overhead lines (taps) and lug connections to equipment such as transformer bushings, switching and protection devices. The inspections use thermographic imaging devices that can record and display the temperature profile of a power line component. Anomalies and variations can be easily identified and trigger levels or alarms can be set to assist the operator. 5.4.2. Background Conductors and joints can fail due to corrosion or imperfect jointing practices. Imperfect joints have a higher resistance to electricity flow. A good joint should be of similar resistance per unit length to the conductor to which it is connected. At low loads, the temperature of an imperfect joint is low and the temperature rise in the joint is small. As the current passing through the joint increases, the temperature of the joint increases due to its higher resistance. As the power loss is proportional to the square of the current, high temperatures occur at a poor joint under high load currents. Sections of corroded conductor are also affected in this manner. At high loads or during the passage of fault currents, temperature of imperfect joints or corroded conductor sections may become excessive, causing the conductor or joint to fail. Sparks can be created and molten metal may fall to the ground from overhead power lines causing fire starts. Thermographic inspections undertaken during high load periods can identify corroded conductors, poor joints and terminations. 21 Recommended Bushfire Risk Reduction Strategies SA Power Networks carries out thermographic inspections as follows: - 5.4.3. 66kV and 33kV assets at 2 and 3 yearly intervals respectively; Greater metropolitan 7.6kV and 11kV lines every 2 years; and Country 11kV & 7.6kV assets at 5 yearly intervals. Industry Practice Thermographic inspection is one of the tools used widely by Australian DNSPs. 5.4.4. Costs The annualised cost of thermographic inspections for SA Power Networks assets ranges from $0.3m to $0.45m per annum, based on the current testing frequency. Increasing the extent of thermographic inspections of rural 11kV & 7.6kV lines from main backbone segments only to all line segments would increase the costs marginally. 5.4.5. Discussion and implementation strategy Examination of fire start records indicate that a significant number of fire starts may be avoided in H/MBFRA with effective thermal inspections. For example, the defect on the LV switch in the installation in Appendix 2 would require the use of thermographic equipment to pinpoint its location. This fault would not have been visible to the inspector who visited the site a few weeks earlier. A reasonable implementation strategy may be as follows: 1) Undertake thermographic inspections in HBFRA for 11kV, 33kV and LV at five yearly intervals during summer peak load periods. 2) Undertake thermographic inspections in MBFRA for 11kV, 33kV and LV at five yearly intervals during summer peak load periods. The costing of these options is based on the difference in expenditure between the current regime and the proposed regime. Table 10: Implementation Strategy Costings for Increased Thermographic Inspections 2015/16 Cost: MBFRA and HBFRA $0.5m 2016/17 $0.5m 2017/18 $0. 5m 2018/19 $0.5m 2019/20 $0.5m 22 Recommended Bushfire Risk Reduction Strategies 5.5. Install Surge Arrestors 5.5.1. Description Electric power systems are exposed to unsafe overvoltages caused by lightning and switching surges. Such over-voltages can damage insulation and equipment. To protect the equipment, and avoid either a catastrophic failure or a weakening of the equipment, devices are installed to detect and discharge over-voltage surges to earth. Rod Air Gaps (RAG) and Current Limiting Arcing Horns (CLAH) are a low cost form of overvoltage protection that have been used widely in SA Power Networks for many years. Rod Air Gaps are applied to high voltage insulators and comprise usually three metal rods arranged to provide two air gaps between the high voltage connection and earth. CLAHs are a series combination of a rod gap and a non-linear current limiting zinc oxide resistor. Conduction to earth occurs during an overvoltage event of sufficient magnitude to break down the insulation of the two air gaps in the case of Rod Air Gaps and the one air gap in the case of the CLAH device. Surge arrestors (or arrestors) are more expensive than RAGs and CLAHs, but provide an effective and gap-free form of overvoltage protection. As they have only been used by SA Power Networks since 2003, there are many CLAHs and RAGs still in service. In recent years some of these devices have been replaced with Surge Arrestors, but this has been on an opportunity basis only. 5.5.2. Background SA Power Networks’ historical practice was to install RAGs or CLAHs on 33kV, 19kV and 11kV power lines as an economic overvoltage protection method. While these devices are low cost, they suffer from a number of deficiencies: - - 5.5.3. The accuracy and repeatability of voltage breakdown varies because the breakdown characteristic is dependent on accurate setting of the rod gaps and varies with humidity and rain. This aspect means that there may be failures of insulation and conductor burning due to poor overvoltage protection performance of rod gaps; Because the rods are un-insulated, there is the potential for animals, birds and airborne vegetation to bridge the air gaps causing a flashover; When the devices operate, there is a power frequency follow-through current that can cause sparks and molten metal to drop, creating a fire start risk; and Electromagnetic interference may be generated during a flashover. Industry Practice RAGs are rarely used by other Australian DNSPs due to their low accuracy in surge voltage suppression and their vulnerability to bypassing (caused by animals and birds). A typical report form for this defect is shown in Appendix 1. Most Australian DNSPs use surge arrestors for their power line overvoltage protection. 5.5.4. Costs The replacement of 33kV RAGs or CLAHs with surge arrestors costs about $4,670 per three phase set. The replacement of 19kV RAGs or CLAHs with surge arrestors costs about $2,007 each. 23 Recommended Bushfire Risk Reduction Strategies The replacement of 11kV RAGs or CLAH with surge arrestors costs about $3,755 per three phase set. 5.5.5. Discussion and implementation strategy Examination of SA Power Networks’ fire start records indicates that a significant number of fire starts in H/MBFRA could have been prevented if RAGs had been replaced with surge arrestors – refer to Appendix 1. The implementation strategy should use the results of fire consequence modelling to identify locations of highest consequence. Feeders should then be prioritised on the basis of: Which line voltages lead to the most fire starts; Which feeders have the highest numbers of CLAHs or RAGs to replace; and Where there is a history of fires starting due to bird interference with line hardware. Table 11: Proposed Implementation Strategy Costings for Installing Surge Arrestors 2015/16 Replace targeted RAGs or CLAHs with Surge Arrestors in HBFRA $2.4m 2016/17 $2.4m 2017/18 $2.4m 2018/19 $2.4m 2019/20 $2.4m 24 Recommended Bushfire Risk Reduction Strategies 5.6. Ground Fault Neutralising Technology 5.6.1. Description Ground Fault Neutralising (GFN) or Reduced Earth Fault Current Limiting (REFCL) equipment is new technology that has the potential to reduce the incidence of fire starts by high speed detection of earth faults in three phase power systems and rapid reduction of earth fault currents. Reducing earth fault currents and fast fault clearing time, reduces the energy into a fault. This reduced energy lowers the possibility of arcing and hence the potential for ignition of combustible material at the fault site. 5.6.2. Background Most Australian DNSP networks utilise balanced three phase high voltage feeder networks that are supplied from a star connected zone substation transformer with the neutral conductor connected to the mass of earth. Earth faults can occur when the phase conductor is connected to earth via a range of events including contact with vegetation, animals and insulation failure. When these events occur, the power system becomes unbalanced and a current path to earth is initiated that can create extremely high currents typically of many hundreds or thousands of amperes. The earth fault current is detected by protection systems that operate circuit breakers or switches to disconnect the fault for safety. GFN technology requires new equipment and control systems to be installed in zone substations. The GFN controller monitors the power system and detects unbalanced earth fault. The GFN injects voltages and currents that re-balances the power system and provides high speed earth fault current reduction. 5.6.3. Industry Practice GFN technology was initially developed in Europe to improve network reliability by eliminating protection triggered disconnection due to earth faults. Normally, the earth fault detection would disconnect the feeder, thus limiting the risk of any unsafe condition for equipment or people. The GFN permits the network to continue to operate safely until the defect can be assessed and rectified by field staff. The earth fault reduction achieved by GFN technology provides a tool to not only improve network reliability but also to reduce the incidence of fire starts. This technology is being used in New Zealand for reliability purposes and trial installations are underway in Victoria following the PLBSTF recommendations to investigate new technology to mitigate bushfires. For the GFN technology to function, the network cannot have any phase to ground connected loads. SA Power Networks has some phase to earth connected distribution transformers and pole mounted star connected power factor correction capacitor banks installed. Insulation of equipment and lines must be able to withstand full line to line voltage on what is normally phase to earth insulation. Distribution transformers, cables and overhead line insulators are generally designed for the increased voltage, but equipment such as surge arrestors and substation voltage transformers must be checked and replaced if under-rated. Fault finding is also problematic as standard line fault indicators will not function correctly and there is little visible evidence of the earth fault location due to the reduced fault energy. 25 Recommended Bushfire Risk Reduction Strategies 5.6.4. Efficiency This technology is relatively new to Australia but results interstate suggest SA Power Networks should investigate its application in South Australia. The PLBSTF estimated that a 70% reduction of fires starts may be achieved. Tests conducted by Marxsen and HRL Technology on a real electricity distribution network confirmed that when a live high voltage conductor falls to the ground under worst case fire weather conditions, such as those experienced on Black Saturday 2009, GFN technology can reduce the conductor-soil arcing in many circumstances to levels below that required to start a fire.10 5.6.5. Typical Costs The installation cost of this technology varies depending on the amount of ancillary work required, but is in the range $1 million to $6 million per zone substation. Table 12: Typical Installation Costs for GFN technology Substation Type Small <=2.5MVA GFN approx. Installation cost per Zone Substation Type Medium 2.512.5MVA $1.0m Large >12.5MVA $2.5 $6m Table 13 identifies the numbers and range of zone substation sizes and their associated bushfire risk area location. Table 13. SA Power Networks 11kV Substations. Substation Type 10 Small <=2.5MVA Medium 2.512.5MVA Large >12.5MVA Total HBFRA 12 30 7 49 MBFRA 52 44 2 98 NBFRA 5 29 83 117 Total 69 103 92 264 Marxsen (2014) 26 Recommended Bushfire Risk Reduction Strategies 5.6.6. Discussion and Implementation Strategy Currently SA Power Networks has no practical experience with the installation, operation or maintenance of GFN technology. However GFN technology is said to “…reduce the fault current to very low levels…so that the likelihood of ignition is negligible…” (PLBSTF p.47). Therefore, it is proposed that this technology be installed in two zone substations to test the stated benefits before any proposal is developed to roll out to other zone substations. Other utilities are investigating this technology. Jemena/United Energy in Victoria has installed a unit at its Frankston South substation, comprising of 10 x 22kV feeders (Holmes 2011). A reasonable implementation strategy would be as follows: 1) Install a test rig in association with higher education establishment or contractor to assess fire start under current earth fault conditions compared to GFN conditions; 2) Install zone substation trials with say 2 adjacent substations in HBFRA to assess the extent of network conversion required and to gain operational experience; 3) Install GFN at targeted zone substations in HBFRA where the fire risk is deemed extreme (future reset period). Table 14: Proposed Implementation Strategy Costings for GFN Technology 2015/16 GFN test rig 2016/17 2018/19 2019/20 $1.0m Trial Installations at 2 Large adjacent substations in HBFRA Total Cost 2017/18 $1.2m $4.0m $5.0m $2.0m $4.0m $5.0m $2.0m 27 Recommended Bushfire Risk Reduction Strategies 5.7. Re-construct Metered Mains 5.7.1. Description ‘Metered mains’ refers to the electricity infrastructure between the revenue meter and the customer’s switchboard, where the switchboard is remote from the meter. Metered mains are typically found on SWER lines, usually where multiple buildings or bore pumps owned by a single customer are supplied from a single meter, or multiple meters if there are multiple tariffs. An example of a metered mains installation is shown below: Figure 3 – Typical metered mains installation. During routine inspection support poles and some lines were found on the ground. These are evident in the foreground. The defective line was made safe pending ownership clarification. 5.7.2. Background Metered mains were created to reduce the time taken for meter reading by co-locating all meters for a property close to or adjacent to the road. Unfortunately, metered mains were constructed to various standards, the ownership of the asset between the meter and the customer’s switchboard is unclear and the condition is often poor due to lack of maintenance. Some installations use trees, railway iron or wooden poles to support the overhead conductors. 28 Recommended Bushfire Risk Reduction Strategies Metered mains present a public safety risk and bushfire start risk. Recently, SA Power Networks has commenced a programme of formally recording the locations and condition of Metered Mains installations in preparation for their resolution. 5.7.3. Industry Practice Good industry practice is to establish and allocate ownership of all electricity infrastructure assets. The responsibility for safety, maintenance and replacement is then clear, as is the liability for damages in the event of failure or fire start. There is a statutory obligation (e.g. Work Health and Safety Act 2012) for any person owning or operating electrical infrastructure to take reasonable steps to ensure the infrastructure or installation is safe and safely operated. This issue is similar to the Essential Energy low voltage private line undergrounding incentive scheme, where there is a distributor-funded incentive to underground low voltage private lines that have defects, vegetation management or end-of- life issues. 5.7.4. Implementation Strategy There are an estimated 5,000 metered mains installations in HBFRA and MBFRA in South Australia. Predominantly, they are supplied from SWER and located in rural areas. There is limited valid data available for detailed scoping of this project. Consequently, a structured implementation plan will need to be developed, comprising: Identification of metered mains locations, asset details including number of poles, conductor spans and asset condition; Risk assessment and prioritisation of remedial work; Implementing a program to upgrade, repair or relocate assets; and then Identification and documentation of ownership including formal advice to customers. Jacobs understands that: SA Power Networks personnel have recently commenced recording details of Metered Mains installations, including their current condition, so that an estimate can be made of the scope of works required to make these installations safe. This work should be completed by the end of 2014; When unsafe installations are found, they are being made safe until a final solution is implemented; and SA Power Networks proposes to restore identified metered mains to sound operating condition before final ownership is established. This should be discussed with the Office of the Technical Regulator in SA. Based on an expectation that all installations will require SA Power Networks’ input, current estimates are that around $6.6M per annum will be required to make the estimated 5,000 installations safe. 29 Recommended Bushfire Risk Reduction Strategies Table 15: Proposed Implementation Strategy Costings for Reconstruction of Metered Mains 2015/16 Reconstruction of metered mains $4.1m 2016/17 $8.2m 2017/18 $8.2m 2018/19 $8.2m 2019/20 $4.1m 30 Recommended Bushfire Risk Reduction Strategies 5.8. Backup Protection 5.8.1. Requirement Backup protection is intended to operate when a system fault is not cleared by the main protection because of failure or inability of the main protection to operate. Within the industry, backup protection is said to be adequate when a credible HV fault on a feeder is cleared in less than two seconds when the frontline protection device or fault breaking device fails. Further, the National Electricity Rules in Chapter 5, S5.1.9 Protection systems and fault clearance times requires that; (c) Subject to clauses S5.1.9(k) and S5.1.9(l), a Network Service Provider must provide sufficient primary protection systems and back-up protection systems (including breaker fail protection systems) to ensure that a fault of any fault type anywhere on its transmission system or distribution system is automatically disconnected in accordance with clause S5.1.9(e) or clause S5.1.9(f). Clause S5.1.9 requires that; (f) The fault clearance time of each breaker fail protection system or similar back-up protection system of a Network Service Provider must be such that a short circuit fault of any fault type that is cleared in that time would not damage any part of the power system (other than the faulted element) while the fault current is flowing or being interrupted. 5.8.2. Background SA Power Networks has numerous locations in their network where backup protection does not meet the adequacy criteria. They are most commonly found where HV lines and transformers are only protected by highside fuses. The longer the conductor and the smaller the size of conductor, the lower are the fault levels and hence the more difficult it is for fuses to detect the expected range of faults. Historically, SA Power Networks has relied on one set of protection for rural feeders based on the use of hydraulic reclosers, as these reclosers have been reliable in the past. However, recent events (refer Appendix 3) have shown that they are not fail safe and many are reaching end-of-life with increasing failure rates. On 30 April 2013 a bulldozer operator pushed a tree branch onto a SWER line resulting in 4 spans of conductor on the ground. As the backup protection was inadequate, the conductor remained on the ground alive, with workmen in close proximity. The fault was only cleared when the transformer supplying the SWER line failed catastrophically. By contrast, on 23 March 2013 a fault occurred at a substation. The primary protection failed and the substation fault was instead adequately cleared by backup protection at the source of supply for that substation. A conductor remaining on the ground alive increases the risk of starting a fire. As stated previously, at the VBRC11 it was agreed that the probability of a fire starting from a downed conductor increases significantly if the fault clearing device operates slowly and operates a number of times. 11 Transcript of Victorian Bushfires Royal Commission, Tuesday 17 November 2009, pp 11103-11106 31 Recommended Bushfire Risk Reduction Strategies The recent increase in hydraulic recloser failure rate, combined with higher expectations of utility asset performance following bushfire investigations in South Australia and Victoria, has increased the urgency for ensuring back up protection is adequate. 5.8.3. Industry Practice Good industry practice, and the minimum requirement, requires compliance with the National Electricity Rules. The practice of other DNSPs is to adequately protect their HV networks with primary and backup protection. SA Power Networks must upgrade its network accordingly. 5.8.4. Implementation Strategy The most economical method of providing back up protection is the installation of electronic reclosers with SCADA. Electronic reclosers operate with high speed and have an extensive range of protection settings and capability that can be varied to suit the specific application. Installation of these devices will reduce the risk that assets are inadequately protected against fault, hence lowering fire start risk. As these devices will be remotely controlled, their protection can be reset to single shot operation and switched off remotely if required. It is estimated that the work to align the backup protection to industry standards will require a 10 year program to complete. This program will need to be coordinated with the recloser installation proposed in Section 5.1.1 to ensure that the programs are merged without duplication. Table 16 provides an estimate of the per annum cost to complete the installation of SCADA reclosers to provide backup protection for the HBFRA, over the 5 years of the 2015-2020 Reset submission. Table 16: Proposed Implementation Costings for Backup Protection 2015/16 Backup Protection $2.9m 2016/17 $3.0m 2017/18 $3.4m 2018/19 $3.6m 2019/20 $5.6m 32 Recommended Bushfire Risk Reduction Strategies 6. Recommended Strategies for AER Submission 6.1. Good Industry Practice Jacobs considers it prudent for SA Power Networks to implement additional risk mitigation strategies as: The VBRC found that the events of Black Saturday called for “material reduction in the risk of bushfire caused by the failure of electrical assets”. A similar expectation is likely to apply within South Australia; The subsequent PLBSTF identified a range of initiatives to reduce the likelihood of powerlines starting bushfires. Some of these are applicable to the distribution network in South Australia and are likely to now be considered as good industry practice within Australia; and General community expectation is that bushfire starts from electricity network assets are preventable by the network owner. Litigation against network owners has arisen from numerous bushfire events in Victoria and Western Australia in recent years. SA Power Networks must ensure that it complies not only with regulations, but also with good industry practice that has evolved following the extreme interstate events to include: - Effective risk management processes; - Upgrading of obsolete equipment to modern construction; - The installation of modern remote controlled technology for control, fault detection & protection; - Efficient and effective asset inspection and monitoring procedures that trigger appropriate and timely maintenance regimes; and - Trialling of new technology. While SA Power Networks has the statutory ability to disconnect supply, disconnections can only be undertaken when extreme conditions justify such action. SA Power Networks’ disconnection capability and processes reduce, but by no means eliminate, the risk of fire starts from network assets. Further risk mitigation requires on-going investment in network assets. 33 Recommended Bushfire Risk Reduction Strategies 6.2. Detailed Strategy Analyses - Summary 6.2.1. General SA Power Networks requested that Jacobs use the network management experience and engineering judgement of its project team to recommend a practical, cost-effective package of risk mitigation strategies required for SA Power Networks to comply with current good industry practice. Eight ‘Recommended’ strategies are summarised below, with estimated implementation costs for a five-year period tabled in Section 6.3. These eight strategies and implementation options have been selected to target the issues and areas of highest fire start risk, accommodate SA Power Network’s capability to execute and provide optimum fire risk mitigation benefits at a modest cost. SA Power Networks should apply risk management principles to assess the probability and consequence of fire starts for each of its feeders in high bushfire risk areas. Typically, - The probability of a fire start for a particular feeder is influenced by the reliability history, fire start history, length of line, frequency of fire bans, and voltage; - The consequence of a fire start is derived from the maximum probable loss from a fire (estimated using bushfire attack levels and loss calculations based on historic fires). These risk assessments produce a ‘feeder risk ranking’ which assists selection of the appropriate strategy and priority for each feeder within a staged work program. Jacobs notes that Victoria’s Powerline Bushfire Safety Program (PBSP) includes works valued at $750 million over 10 years, including a commitment of $200 million to replace powerlines in ‘areas of the highest consequence risk’. Planned works include insulated overhead powerlines, underground powerlines, and the upgrade of reclosers. 6.2.2. SCADA reclosers for 33kV, 19kV and 11kV Progressive replacement of ageing and inflexible 33kV, 19kV and 11kV reclosers with modern SCADA devices would allow SA Power Networks to operate in a manner consistent with current good industry practice. Modern reclosers, with remote control and monitoring, improve operating safety by enabling remote disconnection on extreme fire risk days or remote disabling of reclose operations. The implementation strategy costs shown in Section 5.1 assume the capability of SA Power Networks to upgrade ~35 reclosers per annum in total (covering 33kV, 19kV and 11kV). 6.2.3. New LV, 11kV and 33kV construction The targeted reconstruction of bare conductor by either placing it underground or rebuilding with an insulated form in high-risk locations, based on fire risk consequence modelling, is considered to have the greatest potential for fire start risk reduction. Placing conductor underground would also significantly improve the robustness of supply to Bushfire Safer Precincts. The implementation strategy costs shown in Section 5.2 are based on undergrounding of lines to 12 BSP sites over a 5 year period. 34 Recommended Bushfire Risk Reduction Strategies 6.2.4. Asset inspection frequency The frequency of SA Power Networks’ asset inspections is less than other DNSPs. Jacobs recommends that SA Power Networks: - Initially increases the frequency of asset inspections to every 5 years (maximum) for HBFRA and MBFRA; Assesses whether a further increase in frequency of asset inspections (e.g. to 3 years) is warranted for these areas; Gradually increases the frequency of asset inspections for all other areas to 5 years; and Retains the annual pre-bushfire season patrols in their current form. The implementation costs detailed in Section 5.3 cover the additional inspection costs required to achieve that frequency. 6.2.5. Thermographic inspections Effective thermographic inspections during periods of high load can improve the effectiveness of locating conductor and joint defects in power lines. An increased use of thermographic inspections by SA Power Networks is considered necessary to achieve good industry practice. The implementation strategy costs shown in Section 5.4 cover the additional inspection costs required to inspect all line segments every 5 years in the HBFRA and MBFRA. 6.2.6. Surge arrestors Replacement of RAGs and CLAHs with surge arrestors can decrease the risk of fire starts by: - Preventing lightning weakening equipment insulation which then fails catastrophically on a high fire danger day; and The elimination of animals bridging of air gaps. SA Power Networks’ use of rod gaps and CLAH is out of step with, and inferior to, other DNSPs that utilise surge arrestors for overvoltage protection. The implementation strategy costs shown in Section 5.5 cover replacement of 30% per annum of the existing rod gaps in the HBFRA over a 5 year period. 6.2.7. Ground fault neutralising technology Although implementation of GFN technology for bushfire start prevention is in its infancy in Australia, it has potential to reduce fire starts and it would be prudent for this technology to be trialled to: - Provide hard data for fire start reduction purposes; and 35 Recommended Bushfire Risk Reduction Strategies - Assess the installation and operational changes that would be required for roll out in SA. The implementation strategy costs shown in Section 5.6 cover a test rig in Year 2 followed by trial installations at two large substations during Years 3 & 4. 6.2.8. Re-construct metered mains There are approximately 5000 metered mains installations which have been built to various standards and are in poor condition or unknown condition. They represent a public safety and bushfire start risk. This project is considered necessary to resolve ownership issues and reduce public safety risk and fire start risks for these assets. The implementation strategy costs shown in Section 5.7 provide a preliminary estimate. A more detailed risk assessment and scoping study will be required by SA Power Networks. 6.2.9. Backup protection The lack of adequate backup protection increases the risk of fire starts and risk to personal safety. SA Power Networks needs to alter its line protection to re-align it with the National Electricity Rules. 36 Recommended Bushfire Risk Reduction Strategies 6.3. Recommended Strategies and Estimated Costs The eight recommended risk mitigation strategies and estimated costs are summarised in Table 17. Table 17: Recommended Risk Reduction Strategies and Estimated Costs Strategy No. 1 Section and content 2015/16 2016/17 2017/18 2018/19 2019/20 5.1 Replace 33kV, 19kV and 11kV reclosers with SCADA controlled modern units $3.6m $3.6m $3.6m $3.6m $3.6m $18.0m 2 5.2 Undergrounding or insulating LV, 11kV and 33kV lines $5.7m $5.9m $3.8m $6.3m $4.9m $26.6m 3 5.3 Increase the frequency of asset inspections $2.3m $2.6m $2.7m $2.7m $2.7m $13.0m 4 5.4 Extend and increase the frequency of thermographic asset inspections $0.5m $0.5m $0.5m $0.5m $0.5m $2.5m 5 5.5 Replace rod air gaps and current limiting arcing horns with Surge Arrestors $2.4m $2.4m $2.4m $2.4m $2.4m $12.0m 6 5.6 Undertake field simulation, testing and trial installation of Ground Fault Neutralisation Technology $1.0m $4.0m $5.0m $2.0m $12.0m 7 5.7 Reconstruct metered mains $4.1m $8.2m $8.2m $8.2m $4.1m $32.8 8 5.8 Backup protection $2.9m $3.0m $3.4m $3.6m $5.6m $18.5m $21.5m $27.2m $28.6m $32.3m $25.8m $135.6m Totals Total 37 Recommended Bushfire Risk Reduction Strategies 7. References Marxsen,T., Coldham, D., Czerwinski, A. (2012) New Research on Bushfire Ignition From Rural Powerlines Published in the magazine T&D, February/March 2012 Powerline Bushfire Safety Taskforce 2011, ‘Final Report’, ESV website, 30 September 2011, viewed on 5 December 2013, http://www.esv.vic.gov.au/Portals/0/About%20ESV/Files/RoyalCommission/PBST%20final%20report%20.pdf Prof. Holmes, G. (2011) Independent Expert Report on Rapid Earth Fault Current Limiters RMIT University, Report prepared for the Powerline Bushfire Safety Taskforce, 9 September 2011 Prof. Holmes, G. (2011) Independent Expert Report on Automatic Circuit Reclosers (ACR) for Single Wire Earth Return (SWER) distribution lines RMIT University, Report prepared for the Powerline Bushfire Safety Taskforce, 15 September 2011 T&D Magazine Bushfire Ignition Mitigation (2012) Automatic SWER Single Phase Recloser Transmission and Distribution, February/March 2012 Marxsen Consulting (2014) REFCL Trial: Ignition Tests Report prepared for United Energy 38 Recommended Bushfire Risk Reduction Strategies 8. Appendix 1: SA Power Networks fire report - Rod Air Gaps 39 Recommended Bushfire Risk Reduction Strategies 9. Appendix 2: SA Power Networks fire report - hot joint 40 Recommended Bushfire Risk Reduction Strategies Appendix 2 (cont.) installation where fire occurred 19-Nov-2013 41 Recommended Bushfire Risk Reduction Strategies 10. Attachment 1: Summary CV Information The Jacobs project team comprised Phillip Webb, Terry Krieg and Greg Whicker. Their summary CV information is included below: 42 Curriculum Vitae Phillip Webb EXECUTIVE ELECTRICAL ENGINEER Summary of competencies Phil has a Bachelor of Tech. - Electrical Engineering from (SAIT) and he is a Member of the Institution of Engineers, Australia. With over 37 years experience in the Australian electricity supply industry, Phil has specialist knowledge and understanding of National Electricity Market operation as well understanding of Power System Security arrangements in the National Electricity Market. Some of his achievements include Managing operational due diligence process for the transfer to NEMMCO for Market and System Security functions in South Australia, System Control operational due diligence for privatisation of the South Australian Electricity System. He was also responsible for the development and implementation of quality systems for System Operation procedures for System Control functions (Generation, Transmission and Distribution) in South Australia to achieve operating risk minimisation, legal compliance and best practice operation. Major project experience QUALIFICATIONS Managed operational due diligence process for the transfer to NEMMCO for Market and System Security functions in South Australia. Bachelor of Technology – Electrical Engineering (SAIT), 1975 Managed System Control operational due diligence for privatisation of the South Australian Electricity System. CURRENT POSITION Responsible for the development and implementation of quality systems for System Operation procedures for System Control functions (Generation, Transmission and Distribution) in South Australia to achieve operating risk minimisation, legal compliance and best practice operation. Executive Electrical Engineer EXPERTISE Australian Electricity Transmission and Distribution Networks and Equipment Wind Farm Substation and collector group assets, design, installation, operation and maintenance Power System Operational Control, HV switching and HV Equipment Access management National Electricity Market operation and Power System Security Managed downsizing of System Operations Department to achieve real annual operating savings in excess of $1.5M per annum. Negotiated and managed the service provision for real time operational control and monitoring for fast start generation and distribution system control and monitoring, providing improved returns to shareholders. Developed and negotiated operating protocols with customers requiring high voltage connections to the ElectraNet SA Transmission system. Recent project experience Owners Engineer for the connection works for 8 Wind Farms. Hallett Wind Farm SA, Hallett Hill Wind Farm SA, North Brown Hill Wind Farm SA, The Bluff Wind Farm SA, Waterloo Wind Farm SA, Oaklands Hill Wind Farm Vic, Macarthur Wind Farm Vic and; Musselroe Wind Farm TAS. Audit roles including: audits of SA Generators performance Standards for Australian Energy Regulator and Network Performance Audits for ETSA Utilities Review roles for various utilities including: Network Performance review post Cyclone Larry for Ergon, Review of ESCOSA Wind Generation Licensing Statement of Principles and under frequency Load Shedding review for ESPIC, Guaranteed Service Level Review and Transformer Failure Review for ETSA Utilities, Review of Generation Trip events for Flinders Power. Management of Operations Division responsible for the real time monitoring, control and operation of the ElectraNet SA 275/132/66kV transmission system and the provision of control and monitoring services to distribution and generation entities. www.globalskm.com PAGE 1 Curriculum Vitae Terry Krieg ASSOCIATE Summary of competencies A power electrical engineer with over 30 years industry and utility experience. Previously a senior manager at a number of Australian infrastructure utilities in Queensland, South Australia and the Northern Territory, Terry is a leader in the introduction of innovative approaches to standardisation and design, asset management practices and condition monitoring and has significant high voltage electrical plant experience in maintenance, commissioning, testing and diagnostics of power networks plant. QUALIFICATIONS BE Electrical (First Class Honours) Electrical Technicians Certificate CURRENT POSITION Senior Executive Engineer – Power Networks Chairman of CIGRE Study Committee B3 Substations PROFESSIONAL MEMBERSHIPS AND AFFILIATIONS Fellow of Institute of Engineers Australia PEng, APESMA Registered Professional Engineer Queensland (RPEQ) Major projects include studies for major new infrastructure projects, the implementation of new innovative standardised designs, new approaches to maintenance and on-line condition monitoring and asset management of assets. He was introduced major improvements to asset management practices within the power industry and has presented more than 25 engineering and management papers and key note addresses on aspects of strategic asset management to industry conferences in Australia, New Zealand, China, United States and Ireland. Recent project experience Murrindindi Bushfire Investigation, VICPOl, Vic, Australia Alice Springs System Black Investigation, PAWC, Northern Territory, Australia Due Diligence Assessment 500kV Gas Turbine and Switchyard, Vietnam BSI PAS 55 Certification Audit, Abu Dhabi, UAE F-Factor Audit (Fire Start) , Australian Energy Regulator, Vic, Australia S- factor Audit (Reliability Incentives) , SPAusnet, Vic, Australia Asset Management audit for power transmission, Transgrid, NSW, Australia Substation Life Assessment and Asset Management Audit, Horizon Power, WA, Australia Review of Design Standards - Current State Assessment, SPAusnet, Australia Current State Assessment of Substation Design Standards and processes, Western Power, WA, Australia BSI PAS 55 Gap Assessment, Electranet, South Australia Endorsed assessor for BSI - PAS55, IAM (UK) Feasibility Study for establishment of coal gasification plant, Australia Chairman of CIGRE Study Committee B3 (Substations)l Adelaide Tram Power Studies, SA, Australia Graduate Australian Institute of Company Directors (AICD) EXPERTISE High Voltage Substations Power engineering Asset Management Design Standardisation Fault investigations Review of Asset Management Capability, NT, Australia Development of Earth Grid Asset Management Plan, SA Power Networks, SA, Australia Referee/s Hamish McCarter Senior Manager Engineering, Electranet McCarter.Hamish@electranet.com.au +61 8 8404 7136 Rainer Korte Executive Manager Network Strategy and Regulatory Affairs, Electranet Korte.Rainer@electranet.com.au +61 8 8404 7983 Perry Tonking Maintenance Division Manager, Transco peregrine.tonking@transco.ae +971 (2) 6494606 Ben Li Engineering Design Standards Manager, SPAusnet bin.li@sp-ausnet.com.au +61 3 9695 6671 www.globalskm.com PAGE 1 Curriculum Vitae Greg Whicker Role Project Manager, contract formation, contract administration and quality assurance Qualifications Bachelor of Applied Science (Secondary Metallurgy), Adelaide University Graduate Diploma in Management, University of South Australia Fields of Special Compentence Metallurgy for the power industry, particularly metallurgical and non-destructive testing & assessments of aging generating plant Asset management systems and strategies for generating plant and other power station assets Career History 2002 to current Jacobs (previously Sinclair Knight Merz) Project Director of a wide range of power sector projects, including regulatory compliance audits, performance reviews, management system reviews and investigations, including: Review of network performance reporting and network outage management systems for DNSP Technical advice to Victorian Govt during Bushfires Royal Commission Review of network operations centre operations for DNSP Review of management systems, emergency exercises and vegetation management systems for bushfire risk management for DNSP Technical advice on various power system operation issues for TSNPs, network owners, regulatory bodies and planners Asset management reviews of transmission lines for TSNP. Project Manager of various power sector projects, including: Owner’s Engineer role (civil/structural) for several Hallett Wind Farms, Mt Millar Wind Farm, Wattle Point Wind Farm, Starfish Hill Wind Farm, Lake Bonney Wind Farm. 1993 to 2001 TXU, Optima Energy, ETSA Asset Manager Torrens-Torrens Island Power Station Accountable for providing asset management, risk management and environmental management services for Torrens Island Power Station. Managed a group of specialists responsible for: Setting and monitoring engineering, technical and environmental standards for Torrens Island generating assets to ensure plant integrity, optimised maintenance regimes, compliance with statutory requirements and matching of plant capability to the needs of the national electricity market Scoping and managing the establishment and execution of plant modification & refurbishment works undertaken by contract. Developed and implemented a range of asset, risk and environmental management systems, and coordinated all due diligence issues associated with the privatisation of the power station. 1991 to 1993 ETSA-Generation Technology & Services Department Mechanical and Civil Manager / Chief Metallurgist Managed mechanical & civil engineering, metallurgy and draughting specialists supporting power generation and coal mining within ETSA, providing project management, contract management, contract administration, procurement services and metallurgical services. 1970 to 1991 ETSA Chief Metallurgist/Metallurgist Due diligence review of a gas fired power station Audit of asset management for a diesel generator power station CURRICULUM VITAE Greg Whicker