GRID SYSTEM INVESTMENTS

Transcription

1 EB-0-0 Exhibit D Page of GRID SYSTEM INVESTMENTS SUSTAINING PORTFOLIO OVERHEAD SYSTEM The THESL overhead distribution system supplies power to customers at three primary voltages:. kv,. kv, and. kv. The main components of the overhead system are poles, pole-top transformers, switches and other overhead assets such as conductors, fuses, lightning arresters, insulators, and grounding devices. 0 The overhead system has been steadily deteriorating over the past five years. Figure shows the five-year Customers Interrupted ( CI ) numbers directly caused by defective overhead equipment have increased approximately percent. Figure : Customers Interrupted Overhead System The overhead system is also very susceptible to other outage causes such as tree contacts, animal contacts, lightning, and adverse weather conditions.

2 EB-0-0 Exhibit D Page of Figure illustrates the percentage of CI attributable to the overhead system, and that the overhead system is responsible for the majority of the overall CI. Figure : Customers Interrupted Comparison of Overhead and Overall Systems 0 As stated in the 0-0 Electrical Distribution Capital Plan ( EDCP ) in Exhibit D, Tab, Schedule, THESL will address ageing infrastructure as well as system enhancement initiatives in order to maintain and improve reliability. Like-for-like replacement of aging assets is performed on the assets at or beyond their useful lives. Each asset is replaced in accordance with new standard specifications. This provides for better performance, reduced environmental impacts, and mitigates employee and public safety risks. System Enhancement initiatives are based on reconfiguration of system assets. The major focus is on reconfiguring the trunk portion of a feeder. A trunk portion of the feeder is a main distribution line which supplies power directly from a station. A lateral portion of the feeder is a distribution line which branches out form the trunk. Should an

3 EB-0-0 Exhibit D Page of outage occur on a trunk, approximately,000 customers will be out of power whereas less than 00 customers will be affected if the outage occurs on a lateral. Figure illustrates that the majority of CI is attributable to trunk rather than lateral portions. Figure : Lateral vs Trunk CI Contribution 0 THE OVERHEAD WORK PROGRAM Figure illustrates the overhead projects to be undertaken during 0-0. A summary description of these projects is provided below.

4 EB-0-0 Exhibit D Page of Figure : Map of Planned Overhead Projects for 0-0 The following Table illustrates the capital budget of the Overhead Sustaining portfolio for the historical, bridge and test years. Table : Overhead Sustaining Capital Summary ($ millions) 00 Actual 00 Actual 00 Actual 0 Bridge 0 Test 0 Test 0 Test Overhead Substantial additional capital expenditures are required for overhead systems starting in year 0. The 0 overhead capital budget is $. million. This amount is necessary to address the steep trend of declining overhead reliability and reduce the portion of overall system interruptions attributable to the overhead system. The 0 figure

5 EB-0-0 Exhibit D Page of 0 represents an additional $0. million over 0 to meet the following requirements: Increase ageing asset replacement Increase system enhancement reconfiguration needs Address rear lot conversion that had been initially driven through the underground portfolio during 0 Remove box construction plant Expand feeder automation Address insufficient tree-proof conductor Remedy improper protection Increase fault circuit indicators 0 During 0, an additional $. million is required compared to 0. This increase is primarily needed to address the following overhead system conditions: Lack of sufficient feeder tie-points Overloaded feeders Undersized primary wire Insufficient lateral ties Coordination of lateral fuses Insufficient animal guard protection Overloaded pole mounted transformers Conversion of trunk portion of feeders to fused laterals During 0, an additional $. million is required compared to 0. This increase is primarily needed to address the following conditions: Insufficient feeder tie-points Additional requirements for removal of box construction plant Relocation of assets away from high salt contamination areas

6 EB-0-0 Exhibit D Page of Table illustrates the major units and quantities required during 0-0. Table : Planned Investment Schedule Poles,,, Remote Switches Conductors (km) Fuses 0,0, Animal Guards 0,, Fault Circuit Indicators ( FCIs ),,, Insulators,,0, Pole Mounted Transformers, Box Construction - kv Feeder Removal (km) Ageing Assets Poles Spot replacements are determined from a pole testing program, from field assessment conducted by experienced field crew members, and by engineers. As a result of this data, THESL will replace approximately,000 end-of-life poles during 0-0. These poles are distributed across the city specifically in the areas of Fairbanks TS, Bathurst TS, Horner TS, Finch TS and municipal stations. The remaining poles mentioned in Table will be replaced through other themes described below. In deciding whether to replace a pole that has reached the end of its useful life, THESL considers several alternative approaches. THESL compares like-for-like replacement of ageing assets against upgrading the circuit to a higher primary voltage. Figure illustrates a typical residential area where field data indicates the existence of end-of-life poles requiring replacement.

7 EB-0-0 Exhibit D Page of Figure : Replacement of End-of-Life Assets 0 Figure illustrates a proposed project relating to a Finch TS feeder, namely NYM. As is evident from the field data above, more than percent of the poles in this area require replacement. It is important to note that during replacements of the poles, other under-performing assets are also replaced such as the porcelain insulators. Furthermore, the NYM feeder has sustained eight outages in the past year and is in the worst six percent of the feeders with respect to CI and CHI contribution. THESL uses the rebuild of ageing assets as an opportunity to address system enhancement issues. This approach will improve system reliability, efficiency, and safety. Replacement of Underperforming Assets The 0-0 overhead capital program s focus is to replace porcelain insulators on feeders near Leslie TS, Agincourt TS, Leaside TS, Runneymede TS and Fairbanks TS.

8 EB-0-0 Exhibit D Page of Much of the equipment in these areas is under-performing. The majority of replacements will occur on the.kv system. Underperforming porcelain insulators are replaced with polymeric type insulators as part of aging assets rebuild and/or enhancement projects. Figure illustrates the existence of porcelain insulators on poles in good condition. Figure : Replacement of Underperforming Insulators 0 In the area shown in Figure, out of 0 locations contain porcelain insulator that are underperforming. This feeder, YKM, is supplied by Runnymede TS. During a recent insulator related outage in 0 on this feeder,, customers experienced an outage that lasted over two hours. Rehabilitation of Worst Performing Feeders As the overhead distribution plant gets older, the probability of failure increases rapidly. This has resulted in a large number of sustained outages on older feeders. Furthermore,

9 EB-0-0 Exhibit D Page of certain feeders have sustained many more outages than others. In the 0-0 capital program, rehabilitation of feeders is conducted across the city with particular focus on the worst performing feeders ( WPF ). These areas include feeders related to Agincourt TS, Bathurst TS, Bermondsey TS, Cavanagh TS, Fairbanks TS, Fairchild TS, Finch TS, Leslie TS, Runnymede TS, Warden TS and some municipal stations. As part of the rehabilitation of the feeders, efforts are made to combine resources and also replace under-performing and aging assets. Table lists some of the feeders where overhead projects relating to worst performing feeders are planned for Table : Worst Performing Feeders Feeder FESI CI CHI SAIFI SAIDI Contribution Contribution M,, M,, M,0, M 0,0, SS-F,, M,, M0,0, M,, M 0,, M 0,, M 0,, M, M,, NTM,0, M, M,, NA0M,0, NARM 0,0, 0.0. SS-F,

10 EB-0-0 Exhibit D Page 0 of Feeder FESI CI CHI SAIFI Contribution SAIDI Contribution M, M,, M, SS-F,, Total,, The feeders shown on Table have high number of sustained outages, high CI and CHI values, and include Feeders Experiencing Sustained Interruptions ( FESI ). Based on the FESI and WPF analysis, capital projects have been identified to address these feeders over the next three years. 0 Voltage Conversion Many parts of the.kv system have been in service since the mid 0s. Based on the age of these assets, heath index information, feeder patrols, and crew expertise, most of them are past their useful life. As part of the 0-0 overhead capital program, THESL plans to rehabilitate and convert portions of the. kv-system across the city to a higher voltage. During 0-0, these conversions will be conducted such that after conversion the feeders will be supplied by Manby TS, Richview TS, Bermondsey TS, Sheppard West TS and Dupont MS. Figure illustrates the end-of-life condition for assets slated for a. kv conversion project.

11 EB-0-0 Exhibit D Page of Figure :. kv Conversion Project Figure shows a planned project for the voltage conversion for Queensway MS. It shows that all poles are required to be replaced based on field data. In addition, these feeders have reached or are approaching end-of-life conditions. 0 Feeder Automation ( FA ) For 0-0 THESL will continue grid modernization initiatives to integrate proven automation solutions into the existing distribution system. Grid modernization has evolved into an integrated planning and operational model. THESL plans to install FA schemes for overhead trunk portions of feeders to improve reliability. Automated remote fault sensing switches will be installed on feeders throughout THESL s distribution system. This will continue the successful implementation of FA started in 00. Figure illustrates the areas where THESL plans to expand FA schemes during 0-0.

12 EB-0-0 Exhibit D Page of Figure : Map of Planned Feeder Automation Areas (00-0) 0 Lack of Sufficient Feeder Tie-points THESL plans to extend feeders to ensure there are adequate distinct tie-points for each feeder. This will have an effect of improving reliability. Distinct tie-points will be constructed on feeders that do not currently have sufficient tie-points. The focus between 0 and 0 is specifically for areas where feeder automation is planned. This will enable the feeder automation schemes to be more effective. The following Figure shows the areas with insufficient feeder tie-points.

13 EB-0-0 Exhibit D Page of Figure : Map of Feeder Tie-points Overloaded Feeders To relieve overloaded feeders, THESL plans to rearrange and extend feeders. This will reduce CMOs (Customer Minutes Off). In some cases, feeders will have to be reconfigured in order to provide suitable points of load transfer. In other cases, feeder positions will have to be extended from new circuit breaker positions. Figure 0 shows the location of overloaded feeders.

14 EB-0-0 Exhibit D Page of Overloaded Feeders Figure 0: Map of Overloaded Feeders Insufficient Tree-Proof Conductors THESL plans to install tree-proof conductor along the overhead trunk portion of feeders to reduce CIs. In areas that are heavily treed in close proximity to overhead conductors, tree-proof conductor will replace bare wires. One of the most heavily treed areas is the feeders supplied by Runnymede TS. Table illustrates the areas of focus for 0-0.

15 EB-0-0 Exhibit D Page of Table : List of Feeders Requiring Tree Proof Conductors Station Feeders OH Length Requiring Tree Proof (kilometres) Runnymede TS YKM. Runnymede TS YKM. Runnymede TS YKM. Runnymede TS YKM. Runnymede TS YKM 0. Runnymede TS YKM. Runnymede TS YKM. Undersized Primary Wire THESL plans to replace under-sized wire along the trunk portion of feeders to increase capacity and improve reliability. In areas where there are undersized wires on the overhead trunk portion of feeders, the wires will be replaced with conductor as per THESL s standard construction. In 0-0, THESL plans to prioritize the replacement of undersized conductors on overloaded feeder areas. Figure illustrates areas where undersized conductors are present.

16 EB-0-0 Exhibit D Page of Undersized Wire Figure : Map of Undersized Wire Relocation of Assets from Areas with Salt Spray Contamination THESL plans to relocate overhead assets away from areas where salt exposure is highly probable, such as major highways, to reduce CIs. This will be done in areas where the overhead trunk portion of a feeder is in close proximity to areas susceptible to salt contamination. Figure below illustrates areas whereby overhead trunk wire is susceptible to high salt exposure.

17 EB-0-0 Exhibit D Page of Figure : Map of Overhead Assets Near Highway crossings Insufficient Fault Circuit Indicators Fault Circuit Indicators ( FCIs ) are devices which indicate the passage of fault current on a section of cable during momentary interruptions and forced outages. Table illustrates the feeder locations where THESL plans to install FCIs during 0-0.

18 EB-0-0 Exhibit D Page of Table : List of Stations and Feeders Requiring Fault Circuit Indicators STATION FEEDER STATION FEEDER BERMONDSEY TS NYM RICHVIEW TS ETM NYM YKM NYM ETM NYM ETM EYM ETM NYM ETM NYM ETM EYM ETM NYM ETM NYM ETM NYM0 ETM NYM ETM FINCH TS NYM ETM NYM ETM ETM ETM NYM ETM NYM ETM NYM LESLIE TS NYM MALVERN TS SCNARM NYM SCNARM NYM SCNARM NYM SCNARM NYM SCNARM NYM SCNARM NYM SCARBOROUGH SCNAE-M0 NYM0 WEST TS SCNAE-M NYM SCNAE-M NYM SCNAE-M NYM

19 EB-0-0 Exhibit D Page of STATION FEEDER STATION FEEDER WARDEN TS EYNARM NYM SCNARM RUNNYMEDE TS YKM SCNARM YKM EYNARM NYM EYNARM YKM SCNARM YKM SCNARM0 YKM SCNARM YKM SCNARM YKM SCNARM Total of Stations SCNARM Insufficient Lateral Ties THESL plans to provide lateral ties when a large number of overhead customers are supplied by feeders in a radial configuration. Projects typically include the installation of one or more fuses and a small quantity of poles and conductors. In 0-0, THESL plans to install lateral ties in areas that have high probabilities of failure on the lateral portion of feeders. 0 Conversion of Trunk Portion of Feeders to Fused Laterals Where applicable, THESL plans to reduce the trunk portion of feeders and convert them to fused laterals in order to improve reliability. Areas of focus for 0-0 will be low cost applications requiring a small quantity of fuses, poles and conductors. Co-ordination of Lateral Fuses THESL plans to install adequate and appropriate fuse co-ordination on the lateral portion of feeders. During 0-0, THESL plans to install appropriate fuses in areas that have a high probability of failure. Figure illustrates locations requiring fuses.

20 EB-0-0 Exhibit D Page 0 of Location Requiring Fusing Figure : Locations Require Fuses Insufficient Animal Guard Protection THESL plans to install, animal guard protectors between 0 and 0 on transformers to improve reliability. Priority will be given to the areas where animal contacts during the past five years have caused a high number of sustained outages. Table illustrates the feeders that will be given priority.

21 EB-0-0 Exhibit D Page of Table : Animal Guard Installation 0-0 # of Animal Contacts by Year # of # of Animal Contacts by Year # of Feeder Transformers FESI # Feeder Transformers FESI # Total on Feeder Total on Feeder NYSS F 0 YKM NYSS F 0 0 EYM 0 SCSGF TOADN SCNARM0 ETR0M 0 SCYBF SCNARM SCNAHM0 0 ETNF 00 SCREF SCPJF SCREF ETM 0 NYSS F NYM 0 NYSS F YKM NYSS F NYM NYM 0 0 ETR0M0 0 NYM 0 NYM0 SCNAE M 0 ETM SCNARM 0 ETM SCXJF 0 ETM SCNARM ETRM NYSS F NYM SCNHF 0 SCXGF SCPJF 0 0 TOA0E EYNARM TOA0GL SCKHF TOA0GD ETR0M TOADN NYM 0 ETDAF 0 NYM EYM 0 NYM 0 NYM NYM0 NYM ETRM NY0M NYM NY0M TOADN NYM NYM NY0M0 ETM YKM SCXGF 0 ETM 0 TOA0GD 0 SCNAM TOA0DX 0 0 ETEHF NYM NYM 0 NYSS F SCNAE M ETM YKM NYM ETM ETR0M ETR0M NYM NYM 0 NYM 0 NYSS F NY0M 0 SCNARM NYM TOA0BN 0 TOA0DX TOADN NYSS F YKM 0 SCNAHM NYM ETRM TOAE 0 EYM 0 TOADN NYM ETM 0 NYSS F ETM 0 SCNHF ETM 0 0 EYNARM ETM 0 NY0M SCNAHM 0 0 NYSS F SCXJF 0 ETM TOA0GD 0 NYM TOA0GL 0 0 NYM NYM ETR0M NYM NYM NYM 0 Overloaded Pole-Mounted Transformers Between 0 and 0 THESL plans to replace, overloaded pole-mounted transformers. These transformers are located throughout the city.

22 EB-0-0 Exhibit D Page of Highway Overhead Crossings THESL plans to relocate overhead crossings over major highways. During 0-0, THESL will focus on assets in the areas of QEW to Diesal Drive, QEW and Wickman Road, as well as HWY and North Queen Street. Box Construction Phase Out Box construction is an obsolete construction standard for overhead.kv distribution, found mainly in the downtown Toronto area as shown in Picture below. 0 Picture : Box Construction There are approximately 00 kilometres of box construction.kv circuits in the THESL distribution system. These feeders are shown in Figure below.

23 EB-0-0 Exhibit D Page of Figure : Existing Box Construction Design in THESL s Distribution System Through 0-0, THESL plans to decommission several MS stations and convert their associated kv feeders. MSs to be decommissioned by 0 are College MS, Dufferin B MS, Eglinton MS, Keele & St Clair MS, Overdale MS, Rennie Park MS, Dupont MS, Hazelwood MS, Junction MS, Millwood MS, Kingsway MS, Merton MS, Parkdale MS and Queensway MS. A total of kv box construction feeders from these stations will be converted to.kv/.kv circuits. These stations are shown below in Figure.

24 EB-0-0 Exhibit D Page of Figure : MSs and Associated kv Feeders to be Converted by 0 0 Rear Lot Phase Out Conversion of rear lot distribution plant to front lot has been ongoing since 00 and continues through to 0. Existing rear lot feeders are prioritized for conversion based primarily on age and reliability of the assets. Rear lot feeders exist primarily in the former distribution service area of Etobicoke. The existing feeders are mostly kv and are either overhead or direct-buried underground. As is the standard approach with other proposed kv rebuilds, rear lot is converted to front lot. kv system wherever feasible. This is due to the flexibility this approach provides in configuring load and the marginal reduction in maintenance costs gained by eventually decommissioning the kv station. THESL plans that rear lot areas will be addressed during 0-0. Several of the areas will only be partially converted in this time period due to their relative size. The following Figure shows Planned Rear Lot Conversion Projects.

25 EB-0-0 Exhibit D Page of Figure : Planned Rear Lot Conversion Projects THE DRIVERS OF THE OVERHEAD WORK PROGRAM Ageing Assets Poles Ageing poles with reduced strength not only impact reliability, but can also pose a serious public safety hazard. Picture and Picture below illustrate poles breaking and falling to the ground resulting in high risk to the public.

26 EB-0-0 Exhibit D Page of Picture : Poles After Breaking Picture : Poles After Breaking Based on available asset condition assessment data, shown in Exhibit D, Tab, Schedule, approximately percent of poles will reach end-of-life within the next ten years. As such, a total of approximately,000 poles or,00 poles per year will require replacement during this ten-year period. THESL is scheduled to replace only 0,0 poles during 0-0 due to pole end-of-life condition. THESL will need to accelerate pole replacements in order to avoid unmanageable backlog in future years. 0 In addition to having reduced strength, many poles are cracked or feathered at the top. Picture and Picture illustrate cracked pole conditions at the top and bottom of poles respectively. Cracks are clearly visible at the top of the pole shown in Picture. This portion of the pole holds overhead hardware such as conductors, switches, and transformers and as such supports equipment critical to the operation of distribution infrastructure.

27 EB-0-0 Exhibit D Page of Picture : Poles at End-of-Life (Top) Picture : Poles at End-of-Life (Bottom) 0 Replacement of Under-Performing Assets Under-performing assets in the overhead distribution system are found throughout THESL. Efforts to replace these assets are undertaken to improve reliability. As obsolete equipment, such as porcelain insulators and arrestors, ages it becomes more contaminated. This results in a lower resistance path across the equipment that eventually allows for a voltage discharge, which eventually leads to a semi-conductive track that worsens over time and further weakens the insulator. Furthermore, porcelain insulators are more likely to break, shatter or explode compared to polymeric types. When this happens, fragments of the insulator disperse to the ground. In some cases, this leads to pole fires. Picture shows a broken insulator. Broken insulators can cause outages. For example, the broken insulator shown in Picture resulted in an outage for, customers and a CHI of,.

28 EB-0-0 Exhibit D Page of Picture : Broken Porcelain Insulator Figure illustrates the CI contributions due to insulators and lighting arrestors. Figure : Defective Equipment CI Furthermore, the vast majority of defective insulators are the under-performing porcelain type. Figure shows that the majority of insulator related CI shown in Figure is attributable to porcelain insulators and that there is a trend of increasing failures for porcelain insulators.

29 EB-0-0 Exhibit D Page of Figure : Insulator CI 0 Between 0 and 0 about,000 insulators will be replaced while addressing FESI, WPF and overhead rebuilt in the areas of Fairbanks, Leslie, Bermondsey, Fairchild, Cavanagh, Bathurst, Finch, Richview, Runnymede and Horner station. Rehabilitation of Worst Performing Feeders ( WPFs ) During 0-0, THESL plans to rehabilitate the WPFs. Expenditures on this group of feeders are necessary because they have experienced excessive outages. In fact, almost 00 outages (approximately percent of total outages) occurred on the worst 0 feeders and these feeders are significant contributors to both overall CI and CHI. Continuing outages on these feeders are attributable in part, to ageing equipment, poor condition of equipment, and under-performing inferior asset material.

30 EB-0-0 Exhibit D Page 0 of Table : Outage cause for Worst Performing Feeders Total Outages Outage Source Total Defective Equipment Animal Contacts 0 Adverse Weather Tree Contacts Unknown 0 Lightning Adverse Environment Table illustrates the overhead-related causes of outages on the WPFs. This table shows that defective overhead equipment is a major contributor to outages on the WPFs. THESL currently plans to repair of the 0 WPFs between 0 and 0. 0 Voltage Conversion Expenditures for voltage conversion are necessary because these assets generally cannot be replaced on a like-for-like basis because kv equipment is no longer in general use. As a result, this type of assets has to be custom-made, considerably increasing costs and supply times. When kv circuits are converted to a higher voltage, related assets, such as circuit breakers and station transformers, will no longer need to be replaced. Replacing ageing kv infrastructure and converting to a higher voltage will result in a lower probability of failure. This is because existing higher voltage assets are not as old and are in better condition. The stations that are planned for voltage conversion in the next three years are supplied from Manby TS, Richview TS, Bermondsey TS, Sheppard West TS and Dupont MS, addressing percent of the kv feeders on the system.

31 EB-0-0 Exhibit D Page of 0 Feeder Automation Feeder Automation expenditures are necessary as they provide for effective reliability improvement. Figure, provided above, shows that the trunk portion of the feeder is the main contributor to poor reliability. FA leads to the reduction of the duration of trunk related outages since the self-healing switches quickly isolate the faulted area and restore power within one minute to customers elsewhere on the feeder. In 00, a feeder automation pilot project was successfully completed. This project consisted of creating an FA network of ten feeders. The pilot demonstrated noticeable improvement in reliability under an outage condition. With the expansion to a larger network of feeder automation, typically percent of the customers will be restored within one minute should there be an outage on the trunk portion of their feeder. Picture shows a Supervisory Control and Data Acquisition ( SCADA ) switch located at the trunk of a feeder. Picture : SCADA Switch and Antenna The feeder automation system utilizes S&C SCADA (SCADA-Mate) and Vista switches along with IntelliTEAM II software loaded in each switch controller both of which are shown in Pictures and. Dynamic loading conditions are communicated between the

32 EB-0-0 Exhibit D Page of switches via a peer-to-peer mesh communication network. Upon fault conditions, all switches within the affected segments would initially open to isolate the fault. Picture : Control Unit Picture : Repeater Radio The IntelliTEAM II logic would then analyze the conditions prior to the fault to determine the failed segment. It would then check the available spare capacity on alternate feeders before restoring power to healthy segments. All of this is accomplished through a sequence of automated switch operations without overloading the alternate feeders. 0 Between 0 and 0, THESL plans to focus on the expansion of the existing network of switches within the Fairbanks TS, Bathurst TS, Horner TS, Manby TS, Cavanagh TS, Malvern TS and Scarborough TS. This will allow THESL to utilize the dead open points on the periphery of the existing network. A dead open point is one which has an FA-enabled feeder on one side of the open point and a non-enabled FA feeder on the other side. This open point cannot be used in a self-healing manner to transfer load across the open point. Furthermore, expansion of the existing network also utilizes the

33 EB-0-0 Exhibit D Page of existing base of repeater radios installed from prior implementations. Since a mesh network has already been established, fewer repeater radios will be required. As an illustration, for Bathurst TS and Fairchild TS feeder selection, several criteria were taken into account. These include analysis of trunk outages and the total number of CHI affected. Table illustrates the high contribution of trunk portion of feeder CHI versus the lateral portion of CHI. Table : Trunk CHI and Total CHI Bathurst TS Feeder OH Tie Points UG Tie Points Trunk CHI # of Interruptions Total CHI Total # of interruptions M M M M,, M M M M M,, M M M0 M M M0 M M M,, M M M M0 0M M M M M0 0M 0, M M M M M0 0M 0M 0M 0 M0 M M M M M M 0M M M M M M0 M 0,0 M M M M - 0,0 M M M - 0 Fairchild TS Feeder OH Tie Points UG Tie Points Trunk CHI # of Interruptions Total CHI Total # of interruptions 0M 0M 0M 0M0 0M M M M,0, 0 0M 0M 0M 0M 0M0 M,, 0M0 0M 0M M M 0M 0M 0M, 0, 0M 0M 0M 0M 0M 0M,0, 0M 0M 0M 0M 0M,0, 0M 0M 0M 0M 0M M,, 0M 0M M M - 0 0M 0M0 M 0M - 0,0 0M 0M 0M M - 0 0M 0M 0M 0M M - 0 0, 0 Table also shows the tie-points available for each feeder. The greater the availability of tie-points on a feeder, the more effective restoration will be in the event of an outage. This is due to greater flexibility in load transfer options as well as the lower amount of load required to be transferred to each feeder. Furthermore, focus will also be in the western part of the city where obsolete MOSCAD Remote Terminal Units ( RTUs ) and DARCOM radio systems are still installed. These are no longer supported by the vendor so it is necessary to replace these end-of-life remote switches with FA schemes.

34 EB-0-0 Exhibit D Page of 0 Lack of Sufficient Tie-Points In a looped electrical power distribution system, tie-points are used to restore power to customers during power outages or planned load transfers. Having an adequate number of unique tie-points on each feeder is important to the proper operation of the system. For many feeders, having three distinct tie-points is considered the minimum requirement. Currently, there are a number of feeders in the looped distribution system that have less than three tie-points. These feeders operate properly under normal conditions. However, when a fault occurs and sections of a feeder need to be restored through other feeders, the lack of sufficient tie-points restricts the options for load transfer. Figure illustrates the number of feeders and their associated distinct tiepoints. Figure : Feeder Ties Figure shows that feeders throughout the system do not have adequate tie-points. Of these, feeders have less than two tie-points. A total of feeders without adequate tie-points will be addressed in between 0 and 0.

35 EB-0-0 Exhibit D Page of A tie-point is a critical location whereby two feeders are electrically isolated by a normally open switch. In the event of an outage, the switch can be closed in order to allow for load restoration from one feeder to another. For each unavailable tie-point during an outage on the trunk portion of a feeder, up to percent of customers (typically in excess of 0 customers) will not have their power restored efficiently. Figures 0 and illustrate the effectiveness of installing tie-points. Figure 0: Before Adding Tie-point Figure : After Adding Tie-point 0 0 These figures show the benefits of adding a new tie point and creating section D. Initially,000 customers would be required to be restored from section C in the event of an outage in section B. In this case, there is a risk of the tie-point associated with section C not being able to efficiently restore the entire load. By adding an additional tie-point, section C can be split into two sections (C and D). In this way, there is a better probability of restoring all customers via the two tie-points. Overloaded Feeders Expenditures to relieve overloaded feeders are required. As with feeders with inadequate tie points, highly loaded feeders (i.e. feeders loaded over percent of their rated capacity) do not present a problem under normal operating conditions. However, under a fault condition on the trunk portion of the feeder, an already highly loaded feeder may not be able to accept additional load without experiencing overloading. This prolongs the

36 EB-0-0 Exhibit D Page of outage to the faulted feeder until either repair is complete or lengthy switch operations on other feeders are conducted to re-route power. Figure : Feeder Loading Figure shows feeders that are presently loaded above percent. From 0 to 0, THESL will address of these feeders, which are located across the system. 0 Insufficient Tree-proof Conductor Investment in tree-proof conductors will permanently reduce operating costs for tree trimming. This will be done in many areas within the City of Toronto where mature trees overlap THESL distribution lines. Many outages are caused by tree contact with the overhead lines. When the contact is made on the trunk portion of the feeder, an outage affecting all customers on that feeder will result. An outage of this type typically affects more than,000 customers. In cases where there is a potential for tree contact on the trunk portion of the feeder, the overhead conductor will be replaced by a tree-proof conductor. THESL has identified feeders that have mature trees in close proximity to their trunks. A minimum of eight feeders will be addressed during the 0-0 period. Figure illustrates the CIs due to tree contacts.

37 EB-0-0 Exhibit D Page of Figure : Tree Contact CI 0 Undersized Primary Wire Expenditures to remove undersized wire are required because they impede efficient service restoration. During a fault condition, load is typically transferred from one feeder to another in order to restore as many customers as possible. When a fault occurs on a feeder, the tie-point feeder will be required to carry a higher load than under normal loading conditions. The ability to transfer load may be limited due to an undersized conductor present on the feeder accepting the additional load. Many segments of the overhead system have pockets of undersized conductors. These pockets are weak links preventing efficient restoration of load. Approximately percent of the feeders with undersized wires will be addressed in the three-year period of 0-0. Relocation of Assets from Salt Spray Contamination Areas Distribution assets in proximity to major highways are highly susceptible to salt spray contamination. Insulators break down from contamination. For example, polymer insulators will split or burn (called tracking) when they fail. Glass and porcelain

38 EB-0-0 Exhibit D Page of insulators, however, will break, shatter or explode when they fail potentially producing dangerous shards. At these areas, the overhead distribution usually dips down (via cable riser) to an underground system in order to traverse the major highways. As such, many critical components such as switches and terminations are present. Should an outage occur on these components, typically a total of,000 customers on the feeder will experience an outage. A total of locations were found with assets in close proximity to highways. Approximately percent of these areas will be addressed in the period of Insufficient Fault Circuit Indicators Fault Circuit Indicators reduce the time required to locate the causes of faults, which is usually a time-consuming and costly task. They provide a reliable mean of fault location and isolation to improve the efficiency of service restoration. The presence of fault circuit indicators can also lead to a better understanding of the root cause of momentary outages. When a momentary outage occurs, field crews are not able to determine its root cause as the outage s causal factor is not readily apparent. With the installation of the fault circuit indicators, the crews will know in what section of the feeder the momentary outage occurred, resolve the problem and restore the power to THESL s customers faster. A total of,000 Fault Circuit Indicators will be installed in feeders around Warden TS, Bermondsey TS, Richview TS, Leslie II TS, Runnymede TS, Finch TS, Marlvern TS and Scarborough West TS from 0-0. Insufficient Lateral Ties Low cost solutions can be applied to provide a lateral tie-point where large numbers of overhead customers are supplied by equipment in a radial configuration. Figures and illustrate the before and after scenarios of installing appropriate lateral ties. Figure also shows that any outage on the lateral portion of the outage will affect at least 0

39 EB-0-0 Exhibit D Page of customers. Under adverse weather conditions, the outage duration for these customers could be in excess of two hours. Figure shows that reconfiguration to provide lateral ties mitigates the outage exposure. In this case only 00 customers are affected. Between 0 and 0, THESL plans to install. percent of the total number lateral ties required on the system. Lateral with 0 customers Before Lateral Tie installation Figure : Before Lateral Tie Installation

40 EB-0-0 Exhibit D Page 0 of Lateral with 00 customers After Lateral Tie installation Figure : After Lateral Tie Installation Lateral Fusing THESL plans to re-configure and install normally-closed fuses on both halves of a lateral portion of a feeder as opposed to supplying the customers from only one end. This will reduce the CIs by approximately 0 percent should an outage occur. In the period of 0-0, THESL will install percent of the total lateral fusing required. 0 Conversion of Trunk Portion of Feeders to Laterals In some cases, outages occur on a portion of the feeder lateral that can be fused, but is presently not fused. In this case, more customers than necessary will experience the outage. With a proper fuse installed, typically less than 00 customers will be affected by an outage on the lateral. Without the fuse, all customers on the feeder (more than,000 customers) will be affected by the outage. Approximately 0 percent of the conversion of trunk portions of feeders to laterals will be address in the period of 0-0. Figures and below illustrate the scenario before the conversion of the trunk portion of feeders and after conversion to laterals.

41 EB-0-0 Exhibit D Page of Before Conversion of Trunk Portion CI=000+ Figure : Before Conversion After Conversion of Trunk Portion to Laterals CI=00 Figure : After Conversion

42 EB-0-0 Exhibit D Page of Animal Guard Protection Animal contacts accounted for nine percent of overall outages in 00. THESL plans to install animal guard protection on all transformers to improve reliability. Without this protection, animal contacts usually results in outages, death of the animals and damage to the equipment. Animal guards provide great benefit with respect to costs. From 0 to 0, 0 percent of the required animal guards will be installed. Pictures 0 and illustrate how animal guards work. 0 Picture 0: Transformer without Animal Guard Picture : Animal Guard Standard Overloaded Pole-Mounted Transformers Overloaded pole-mounted transformers are usually the result of growth in customer load. The past decades have seen a large increase in the use of air conditioners, computers and other household appliances. During hot summer days, heavily-loaded transformers can overheat causing outages. Under some conditions, this could result in rupture or fire.

43 EB-0-0 Exhibit D Page of From 0 to 0, 0 percent of the overloaded pole-mounted transformer will be addressed. 0 Highway Overhead Crossings At a number of locations overhead distribution lines cross over major highways. These crossings create an increased concern for public safety should energized lines break and fall onto the road. For example, in one instance an overhead conductor crossing the Gardiner Expressway near Royal York Road failed and fell onto the road. THESL is planning to re-route these overhead highway crossings to minimize the potential for such incidents. This is typically done by undergrounding a portion of the circuit. A total of overhead highway crossings have been identified with approximately 0 percent of these scheduled to be addressed in Box Construction Phase-Out Converting kv box construction to existing.kv overhead or underground construction standards will significantly improve workplace safety for crews. This conversion will inherently eliminate the associated hazards of multiple circuits going through a typical box pole, as well as eliminate the hazard of working in the vicinity of shielded primary cable (found only on kv feeders). In addition, a majority of the box construction feeder assets are old and past their useful life.

44 EB-0-0 Exhibit D Page of Table : Assets Past Useful Life in MSs to be Decommissioned MS Station Number Total number of Total number of Number of nonlinear Number of of non-linear linear assets assets linear assets feeders assets past past useful life past useful life past useful life useful life (m) per feeder per feeder(m) Rennie Park Merton Runnymede Millwood Queensway Dupont Junction Overdale,.. Hazelwood 0.. Eglinton Kingsway Keele & St Clair College Dufferin Parkdale NOTE: Linear assets represent cable past useful life. Non-linear assets represent all other equipment on feeders, and are represented in counts.

45 EB-0-0 Exhibit D Page of There are currently a high number of assets past useful life on the feeders in the MS stations, as outlined in Table. Choosing to first decommission the MSs identified in Figure will result in maintenance cost savings. Eliminating maintenance in these stations will reduce THESL s inventory and maintenance costs for obsolete kv equipment, and result in less station maintenance overall. 0 Figure : Feeders to be decommissioned Decommissioning of these stations will also allow THESL to use the MS land for other projects. Of particular interest is part of the downtown contingency plan to use decommissioned MS land as switching stations between various TSs in the event of a complete TS outage. MSs identified as possible switching points are Hazelwood MS, and Dufferin MS, and those two are to be decommissioned by 0. Some MSs have equipment in need of maintenance and replacement in the near future. One such station is Hazelwood MS. Rather than maintain and/or replace obsolete

46 EB-0-0 Exhibit D Page of 0 equipment in this station by 0, all associated feeders will be converted to.kv and Hazelwood MS will be decommissioned. In addition, historical outage data from shows that average outage duration on.kv feeders is. minutes and on kv feeders is. minutes, demonstrating that outages are typically resolved more quickly on.kv feeders than kv feeders. Rear Lot Phase-Out Outages related to rear lot feeders on average tend to last approximately twice as long as outages related to front lot feeders. This is due to difficulty in accessing and repairing the rear lot feeder equipment as well as the presence of old and non-standard assets and feeder configurations. The lack of access also presents safety hazards to crews during emergency outage situations. 0 Areas for rear lot conversion between 0 and 0 were identified based on reliability and age concerns. Rear lot projects are also driven by the short-term need to convert kv feeders supplied by stations that are reaching the end of their serviceable lives (e.g., conversions near Lawrence and Leslie identified for 0 are driven by the need to decommission Lesmill MS in the short-term). Converting the rear lot areas will improve reliability, specifically lessening outage duration, improve crew safety and reduce inventory and maintenance costs related to the maintenance of obsolete kv distribution equipment and stations. The rear lot areas targeted for conversion in 0-0 due to decreased reliability have each experienced one to three outages per year for the last nine years, with typical outage durations lasting between four to eight hours. Nine of the feeders being addressed in these rear lot areas have experienced at least one outage over hours in duration during the last five years.

47 EB-0-0 Exhibit D Page of THE CONSEQUENCES OF DEFERRING THE OVERHEAD WORK PROGRAM Figure shows the annual risk cost for major overhead asset classes from 0 to 0. Risk Cost Annual Risk Cost $00,000,000 $0,000,000 $0,000,000 $0,000,000 $0,000,000 $0,000,000 $0,000,000 $0,000,000 $0,000,000 $0,000,000 $ Year OH Switches OH Tx Poles Figure : Annual Risk Cost from 0 to0 0 This risk cost is derived from the Feeder Investment Model ( FIM ) that THESL has developed for capital project identification and justification. The economic model takes into account total life cycle cost of each asset including capital installation, operation & maintenance and decommissioning costs. In addition, the model also takes into account failure cost of the asset if it is left to run to fail. Failure cost is based on the condition and age of the asset, the probability of failure based on the risk curve established for each asset class, and social impact and economic loss from each asset failure. It is composed of various direct and indirect cost attributes associated with in-service asset failures including the costs of customer interruptions, the costs of emergency repairs and replacement, and the costs associated with potential catastrophic failures of assets.

48 EB-0-0 Exhibit D Page of Given that a large percentage of overhead assets have passed or are approaching the end of their useful service lives, the risk cost for the overhead system is very high. Delay of planned overhead capital work serves only to increase the risk cost in subsequent years. The result of such postponements is higher operations and maintenance costs, increased capital replacement cost and greater customer outage cost and inconvenience. In addition, further postponement of capital work will call into question the availability of sufficient resources in future years to complete needed work. Figure 0: Duration of Outages Caused by Overhead Assets 0 Ageing Assets Poles Deferral of replacement will lead to continued ageing and deterioration of equipment ultimately leading to an increasing probability of failure. As noted earlier in Figure, CI contributions related to overhead system failures have increased by percent since 00. This is illustrated in Figure 0, which shows that CHI has increased by almost percent between 00 and 00. This increase is an indication that restorations of

49 EB-0-0 Exhibit D Page of outages caused by aged end-of-life assets are becoming more difficult and requiring more time to complete. This is due to reactive replacement of assets that are part of inferior older designs and the additional time required to operate older distribution assets. A reduction of expenditures related to end-of-life equipment replacement between 0 and 0 will certainly result in worsening overhead reliability statistics. Customers will continue to experience an increase in disruptive forced outages. Further deferral of asset replacement will also result in a rapidly increasing backlog of assets requiring attention in the future. 0 The quantified risk of not proactively undertaking pole replacement projects and allowing the poles to fail is approximately $0 million between 0 and 0. This figure includes the costs of customer interruptions, the costs of emergency repairs and replacements, and the indirect costs associated with potential catastrophic failures of assets. Figure shows the risk cost if there is no investment for pole replacement. Figure : Risk Cost Replacement of under-performing assets Consequences of deferral will lead to increasingly poor reliability due to under-

50 EB-0-0 Exhibit D Page 0 of performing assets. For example, industry tests have shown that polymeric type assets have better performance than porcelain type. As these under-performing assets continue to deteriorate, there will be an increased probability of outages. Figure below illustrates the increasing quantity of outages related to insulators. Figure : Insulators Number of Outages 0 Rehabilitation of Worst Performing Feeders Ageing and deteriorating equipment is often the reason that certain feeders have experienced a high number of sustained outages year after year. Currently, more than 0 feeders have sustained seven outages or more during the past year. Depending on outage location, more than,000 customers can be affected. The feeders listed in Table require long-term solutions and significant capital investment in order to reduce the number of outages. Deferring the replacement of the feeders identified in the WPF projects will lead to continued poor, or even worsening,

51 EB-0-0 Exhibit D Page of performance. Figure illustrates the number of outages from 00-0 for the WPF. WPF Outages Figure : WPF 0-0 Outages Voltage Conversion Consequences of deferral would be high station maintenance costs since circuit breakers and station transformers will eventually need to be replaced at the station due to deteriorating asset conditions. The electrical equipment industry has moved away from

52 EB-0-0 Exhibit D Page of.kv equipment and as a result, spare parts for these assets are more expensive and more difficult to obtain. Thus the age of this equipment, its condition and the difficulty of repairing together mean that it will continue to negatively impact both CI and CHI until it is replaced as part of voltage conversion. 0 Feeder Automation Deferral of Feeder Automation (FA) expenditures will result in many peripheral open points in the areas where FA has already been implemented remaining as dead open point nodes. These nodes will not allow the feeders within the current FA scheme to effectively and automatically transfer load. On average, the presence of a dead open point on a feeder will lead to a percent reduction in potential reliability savings. FA is one of the most effective ways to reduce CI/CHI on the overhead system and its widespread adoption should help to mitigate deterioration of the overhead system. As a result, deferral of investment will decrease reliability in the future years. 0 As noted in Figure trunk-related outages are a major contributor to poor reliability. FA is a very effective means of improving reliability performance since the self-healing FA switches efficiently restore customers affected by trunk outages. The 0-0 capital plans for FA will complete the work undertaken since 00. In addition, the MOSCAD system in the western part of the city currently presents a high risk and requires replacement with FA. Not only are the existing automation switches at end-of-life, but the master radio system also is no longer supported by the manufacturer. Failure of the MOSCAD master radio system will lead to more than 0 switch locations becoming incapable of remote operation. Lack of Sufficient Tie-Points Additional tie-points are required to effectively implement FA and reduce the number of

53 EB-0-0 Exhibit D Page of 0 customers impacted by outages on feeders with an inadequate number of tie points. FA improves reliability by significantly reducing the restoration time for the majority of segments of the trunk portion of the feeder. In order to reduce restoration time, sufficient tie points must exist to support the required switching. Deferring investment in additional tie points would increase both the duration of outages and the number of customers likely to be impacted by certain outages. Overloaded Feeders There are presently feeders that have been identified as overloaded within the THESL distribution system. Deferring the work to relieve the feeders will result in longer than normal restoration times in the event of an outage. Insufficient Tree-proof Conductor The following Picture illustrates the close proximity of trees to critical overhead assets. Picture : Trees in Proximity to Distribution Equipment