DISTRIBUTION SYSTEM ASSET CONDITION ASSESSMENT UPDATE

Transcription

1 EB-0-0 Exhibit D Page of DISTRIBUTION SYSTEM ASSET CONDITION ASSESSMENT UPDATE 0 EXECUTIVE SUMMARY Background Over the past number of years, THESL has put considerable effort into its Asset Management Program. In 00, a full Asset Condition Assessment ( ACA ) for key distribution assets was conducted by Kinectrics Inc. ( Kinectrics ). Between 00 and 00, THESL took steps to adopt the recommendations prescribed by the 00 ACA and to improve the quality of its asset condition data. Further, THESL developed the Health Index Calculator, an application that evaluates the Health Indices of assets based on current and best available inspection data. 0 In 00, using this Calculator, an ACA was again conducted by THESL. Kinectrics was engaged to audit the progress that THESL had made between 00 and 00, and to compare the results of the 00 and 00 ACA. Between 00 and 00, THESL continued to improve and to adopt the recommendations of the 00 audit. Kinectrics was asked to assess the changes and ACA results between 00 and 00 and produced a report describing the findings, the 00 ACA Audit. THESL continued to focus on the quantity and quality of data available to the ACA and has made further improvements in 0. This schedule shows a comparison of the ACA results between 00 and 0 and describes the changes. Key Achievements Between 00 and 0 Key achievements are highlighted below: Considerable efforts were made to increase the number of installed and inservice assets with sufficient information for condition assessment.

2 EB-0-0 Exhibit D Page of 0 0 Monthly tracking of maintenance program execution to ensure that all assets which were inspected per their maintenance cycle in the previous month had all inspection data recorded so that a health index is able to be calculated for that asset. Processes initiated to catch and reject maintenance records where the inspection data was incomplete, which and would lead to an asset having insufficient data to calculate a Health Index. This will force a crew to go back to that asset and complete the inspection record in its entirety before it can be submitted for completion and approved. A mobile inspection program was started for some of the maintenance inspections. Inspections are recorded on a handheld device instead of paper, which provides the ability to make inspection fields required by the ACA mandatory for completion, thus preventing inspectors from leaving inspection fields blank. More Wood Pole data has been migrated into the Asset Registry (Ellipse). Detailed assessments were conducted to determine which asset classes currently have data available in Ellipse such that dominant factors could be included in the calculation of the Health Index. For asset classes where there is insufficient data to implement the latest recommended Health Index formulations, THESL is in the process of including the new parameters in the maintenance inspection process. The calculator itself, which is now a Business Intelligence ( BI ) report, is enabling employees across the organization to see near real time asset conditions as the data is updated every hours. This facilitates efficiencies in capital projects as engineers can see which assets need to be addressed sooner based on the most current condition information.

3 EB-0-0 Exhibit D Page of 0 0 Comparison of 00 and 0 ACA Methodology Health Index ( HI ) formulation and results from 00 and 0 were compared for the same Asset Categories that were analyzed in the 00 ACA Audit: Stations Power Transformers Station Switchgear Air Blast Circuit Breaker Air Magnetic Circuit Breaker Oil Circuit breaker Oil KSO Circuit Breaker SF Circuit Breaker Vacuum Circuit Breaker Network Transformers Submersible Transformers Vault Transformers Pad-mounted Transformers ATS (Automatic Transfer Switch) Cable Chambers Wood Poles Phase Overhead Gang (Remote) Switches Phase Overhead Gang (Manual) Switches SCADAMATE Pad-mounted Switches Network Vaults Underground Cables (Direct-Buried XLPE) For all asset classes, the 0 assessments were made using the new business rule for capturing data from the last inspection date.

4 EB-0-0 Exhibit D Page of Audit Results This section describes the results of the 0 Audit. Changes in Health Index Formulation There have been no changes between 00 and 0 with respect to Condition Parameters, Weights and Condition Criteria for any of the assets in the ACA. 0 Changes in Asset Category Granularity The assets within each asset category do not represent a homogeneous set of equipment as there are variations in manufacturers, models, types, ratings, installations, environments, etc. All of these factors have impacts on the condition of individual assets and their corresponding Health Index. Changes in Population and Sample Size Table summarizes the changes in population and sample size included in the ACA between 00 and 0. Graphical representations of the data are given on Figure and Figure. 0 With the exception of Direct-Buried ( DB ) XLPE cable, all data used to calculate the population size, sample size and health index distribution comes from Ellipse. This is the enterprise resource planning ( ERP ) system which THESL uses to schedule the maintenance inspections for and record the inspection results of all assets that have regularly scheduled maintenance. The data used to calculate the Health Index for DB XLPE cable was extracted from the THESL GIS system called GEAR. This data was compiled and assessed separately, using the same methodology and formulation as before.

5 EB-0-0 Exhibit D Page of Table : Summary Changes in Population and Sample Size Population Sample Size % % Sample Population Asset Population Sample Sample Size Count Change % Size Size Change % Stations Power Transformers 0.% 0.%.% 0.% Station Switchgear 0.%.0%.%.% Air Blast CB 0.%.%.% Air Magnetic CB -.%.%.%.0% Oil CB.0%.0%.0% -.% Oil KSO CB.%.%.%.0% SF CB.%.%.0% -.% Vacuum CB 0.% 0.% 0.% Network Transformers -.%.0% 0.%.% 0 Submersible Transformers 0.%.%.%.0% Vault Transformers -0.%.%.0%.% Pad-mounted Transformers 00.0%.%.%.0% ATS -.%.%.%.% Cable Chambers 0 0.%.0%.%.% Wood Poles 00.%.%.%.% ф OH Gang (Rem) Switches 0 -.%.%.% 0.% ф OH Gang (Man) Switches.0%.%.0% -.% SCADAMATE Switches.0%.%.%.% Pad-mounted Switches -.%.%.% -.00% 0 Network Vaults 0 -.0%.0%.%.% UG Cable - DB XLPE.%

6 EB-0-0 Exhibit D Page of Changes in Population Network Vaults Padmounted Switches.0%.% SCADAMATE Switches.0% ф OH Gang (Man) Switches.0% ф OH Gang (Rem) Switches.% Wood Poles Cable Chambers.% 0.% ATS.% Padmounted Transformers Vault Transformers Asset Submersible Transformers Network Transformers 0.%.%.0% 0.% Vacuum CB SF CB.%.% Oil KSO CB.% Oil CB.0% Air Magnetic CB.% Air Blast CB Station Switchgear Stations Power Transformers 0.% 0.% 0.% 0% 0% 0% 0% 0% 0% 0% 0% 00% Population Change between 00 and 0 by Percentage Figure : Changes in Population

7 EB-0-0 Exhibit D Page of Changes in Sample Size UG Cable DB XLPE Network Vaults Padmounted Switches SCADAMATE Switches ф OH Gang (Man) Switches ф OH Gang (Rem) Switches Wood Poles Cable Chambers Asset ATS Padmounted Transformers Vault Transformers Submersible Transformers Network Transformers Vacuum CB SF CB Oil KSO CB Oil CB Air Magnetic CB Air Blast CB Station Switchgear Stations Power Transformers.00%.%.%.%.%.%.%.%.%.%.0% 0.%.%.%.%.0%.%.0%.% 0.%.0%.%.0%.0%.% 0.%.%.%.%.0%.%.%.0%.% 0.% 0.%.%.%.%.% 0% 0% 0% 0% 0% 0% 0% 00% 0% Percent Data Availability 0 00 Change between 00 and 0 Figure : Changes in Sample Size

8 EB-0-0 Exhibit D Page of 0 Changes in Population Population sizes have increased for some asset classes due to capital expenditures to improve system reliability. Of particular note are the population increases for padmounted transformers and SCADAMATE switches. Pad-mounted transformers have increased in population slightly due in part to installing pad-mounted transformers instead of submersible transformers in areas prone to flooding. The population of SCADAMATE switches has increased considerably as THESL continues its efforts to automate the distribution system. Automating these three-phase switches enables power system controllers (or automated software) to isolate faulted sections of feeders within minutes of a fault happening. This greatly reduces customer interruption time compared to the use of manual switches that require a crew to be dispatched. Improvement in data quality has led to changes in populations for manually and remotely operated overhead gang switches. Corrections to classification of switch type within Ellipse has led to a decrease in the population of remotely operated units which has translated to an apparent increase in both manually operated switches as well as SCADAMATE switches. 0 A decrease is also seen in the population of pad-mounted switches, as more robust equipment is being used as replacement in the event of equipment failure. For example, air-insulated pad-mounted switches are being replaced with sealed SF insulated type switchgear for improved reliability. Also SCADAMATE switches are being installed to replace legacy manually or remotely operated overhead gang switches as they reach endof-life to improve system reliability. Changes in Sample Size Efforts focusing on quality improvement have resulted in a sample size increase for out of 0 asset classes as outlined in the above tables.

9 EB-0-0 Exhibit D Page of Network Vaults and Transformers shows significant increase in sample size, due in part to the lack of completed inspection results at the time when the last audit was completed. Sample sizes increased significantly for ATS, Station Switchgear, Air Magnetic circuit breakers ( CB ) and Vacuum CB. 0 0 Generally, a sample size of ten percent is required to extrapolate ACA results over an entire population. The sample size for Station Switchgear, previously less than ten percent, has increased significantly to over percent. Manual Overhead Switch sample size remains below ten percent and showed a small decrease in sample size while remotely operated switches showed a slight increase in sample size. This can be attributed to improvements made in the identification of switch type via field checks; some switches previously recorded as manual were in fact remotely operated while some that were identified as remotely operated were in fact SCADAMATES. This is also a contributing factor to the large decrease in population size for remotely operated overhead gang switches. In summary, the transition of the ACA to a single uniform report accessible to all applicable groups was a large undertaking and a success. Though it is clear that further revisions of the Health Index Calculator are required to make use of all available inspection data, much time and effort is saved by the BI tool, as opposed to manually operating on Ellipse data in an MS Access database. Health Index Distribution Analysis The changes in Health Index distribution between 00 and 0 are summarized in Table.

10 EB-0-0 Exhibit D Page 0 of Table : Summary of Health Index Distribution Asset Year Very Poor Poor Fair Good Very Good % Sample % Change % Sample % Change % Sample % Change % Sample % Change % Sample % Change Network Transformers %.0%.0%.% -.% 0.% 0.%.0% -0.0% Submersible Transformers 00 0.%.%.0% 0.0% 0.%.% 0 0.0%.%.%.% -.% Vault Transformers 00 0.%.0%.%.% 0.% -0.% 0.% 0 0.%.%.%.% -0.% Padmounted Transformers 00 0.%.%.% 0.%.0% 0 0.%.%.% -.% ATS Cable Chambers Wood Poles 00.%.0%.%.% 0.%.% -.%.% 0 0.%.% 0.% 0.%.0% 00 0.%.%.%.%.% -0.0% -0.0% 0.0%.% 0 0.%.0%.0%.%.0% 00.%.%.%.%.% 0.%.% -.0%.% 0.%.%.%.%.% -.% -.% -.% ф OH Gang (Rem) Switches 00.%.%.% -.% -.0% 0.%.%.%.% ф OH Gang (Man) Switches 00.%.%.% -.00% -.% 0.%.%.%.% 0 SCADAMATE Switches 00.% 0.%.% 0.% -0.%.% 0 0.%.%.%.% -.%

11 EB-0-0 Exhibit D Page of Asset Year Very Poor Poor Fair Good Very Good % Sample % Change % Sample % Change % Sample % Change % Sample % Change % Sample % Change Padmounted Switches 00 0.%.0%.0%.% 0.% -.%.% 0 0.%.%.0%.% -.% Network Vaults 00.0%.0%.0%.0%.0% -0.% -0.% -.0%.% 0.%.% 0.0%.%.% -.% Stations Power Transformers 00.0%.%.%.%.% -.%.0% -.%.0% 0.%.00%.00%.%.%.% Station Switchgear Air Blast CB Air Magnetic CB Oil CB Oil KSO CB SF CB 0 Vacuum CB 00.%.%.%.%.% -.%.0% 0.0%.% 0.%.%.%.% 00.%.% 0.%.%.% -.% -.0% 0.0% 0.%.%.0% 00.%.%.%.%.%.% -.% 0.00%.%.%.00% 00 0.%.0%.%.% -0.0% -0.0% -0.% 0.% 0 0.%.%.%.0% 00.0%.0%.0%.0% -.% 0.% -.0% 0.%.%.00%.% 00.%.% -0.% -.% 0.%.%.% 00 0.%.% 0.% -0.0% -.0% -.% 0 0.%.%.%.%.% -0.% -.% -.%.0%.% UG Cable - DB XLPE 00.00%.00%.00%.00%.% -.0% -.0% -.% 0.%.0%.0%.%.0% -0.0%

12 EB-0-0 Exhibit D Page of The general trend for asset classes listed above is that the number of units in Good and Very Good condition is decreasing, while the number of units in Fair, Poor and Very Poor condition is increasing. This is representative of THESL s ageing infrastructure. UG Cable - DB XLPE Vacuum CB SF CB Oil KSO CB Oil CB Air Magnetic CB Air Blast CB Station Switchgear Stations Power Transformers Network Vaults Padmounted Switches SCADAMATE Switches ф OH Gang (Man) Switches ф OH Gang (Rem) Switches Wood Poles Cable Chambers ATS Padmounted Transformers Vault Transformers Submersible Transformers Network Transformers % 0% 0% 0% 0% 00% 0% 0% 0% 0% 0% 00% Very Poor Poor Fair Good Very Good Figure : Health Index Distribution Change Assets within the Health Index Calculator can be grouped into four main categories, stations assets, network distribution, overhead and underground. Though some asset classes can be found in more than one grouping, for instance cable chambers are found in

13 EB-0-0 Exhibit D Page of the network system and also in underground looped distribution, grouping the assets into these categories will assist with the overall system condition analysis. 0 Stations Assets Critical stations assets which the Health Index Calculator computes health indices for are: Stations Power Transformers Station Switchgear Air Blast Circuit Breaker Air Magnetic Circuit Breaker Oil Circuit breaker Oil KSO Circuit Breaker SF Circuit Breaker Vacuum Circuit Breaker 0 Over the last year the number of power transformers in good and very good condition has increased marginally; however there has been a noteworthy shift in the number of units in fair condition, a decrease of over four percent. As transformers have degraded from fair to poor condition, percent of these transformers are now rated as poor. This brings the total to station power transformers that are now either in very poor or poor condition. Very poor units pose the greatest risk to system reliability as they are the nearest to endof-life. These units need to be scheduled for replacement immediately so that plans can be created to replace these units within the next year. Units currently in poor condition are likely to degrade further into very poor condition; as such replacement for these units should be scheduled as soon as practicable as they will be the next units most likely to fail and cause power outages once the units in very poor condition have been replaced. Despite the large number of units in poor and very poor condition, it is important to note that percent of this asset class or power transformers, are currently in fair condition. An important decision must be made for a long-term plan to either increase

14 EB-0-0 Exhibit D Page of the maintenance work performed on these units to extend their useful life, or have them scheduled for replacement as soon as they have degraded into poor or very poor condition. 0 During the 00 audit, over half of the station switchgear asset class was listed in very poor condition. At that time, there was a lack of infrared scan inspection results to use as part of the HI calculation as recommended by Kinectrics. This data has since been acquired and entered into Ellipse. As a result, the number of units previously listed in very poor condition has been reduced to zero. These advanced inspection techniques and their results have enabled THESL to more accurately identify asset condition. THESL will be continuing to seek out new technologies, where applicable, that can be incorporated into maintenance practices with the benefit of developing a more rigorous Asset Management practice. 0 Despite this apparent improvement in the condition of station switchgears, almost 0 percent of the switchgears are still in poor condition. The replacement of these units is a significant challenge to THESL as switchgear decommissioning and replacement requires load transfers to adjacent feeders and stations which may not have available load capacity. To accommodate this work it is possible that other projects, such as voltage conversion, may be required to alleviate the amount of load that needs to be transferred so that the switchgear may be replaced. Long-term plans for increased maintenance on and/or replacement of the 0 units currently in fair condition must also be considered. Though the units are currently in fair condition, within the next ten years they may pose significant risk to system reliability as they degrade into poor and very poor condition. As can be seen from the asset class descriptions, there are currently six types of circuit breakers in use within THESLs distribution system. Despite the difference between the arc-quenching medium used in each type of breaker, all circuit breakers essentially serve the same purpose. As such analysis of the condition of circuit breakers will group

15 EB-0-0 Exhibit D Page of 0 together all types from this point forward. Combining the condition data of all types, 0 units are currently in poor condition and two are in very poor condition. Plans for replacement of the units in very poor condition should be started immediately as these units pose the greatest risk to system reliability of all circuit breakers in the ACA. Plans for the replacement of the 0 units currently in poor condition should be developed as soon as practicable as it is possible that these units may degrade further, into very poor condition, over the next three years. Replacement of 0 poor condition units presents the same challenges as the replacement of station switchgear in that surrounding feeders may not have the load capacity to absorb load transfers to accommodate the breaker replacement. Other developmental work, such as new feeder construction or voltage conversion, may need to first take place. Special attention should be given to the larger volume of circuit breakers (,0 units) currently in fair condition. These breakers will likely degrade into poor and very poor condition, over the next ten years. Long-term plans must be developed to ensure these units are either maintained to delay degradation or replaced after they move to poor and very poor condition. Given the significantly large number of units to eventually replace and the current system load capacity limits, gradually phasing out the units in the worst condition over time may be the only option, short of new station construction. 0 Network Assets Critical network assets which the Health Index Calculator computes health indices for are: Network Vaults Cable Chambers Network Transformers ATS

16 EB-0-0 Exhibit D Page of 0 Since the 00 audit, the number of vaults in poor and very poor condition has shown little change. Of all in-service network vaults, are currently in very poor condition while are in poor condition. Structural repair of these vaults poses a significant challenge in that many are located under main streets in the downtown core. Work to maintain the structural integrity of these vaults may create traffic and pedestrian obstacles and delays. Consequently, THESL may be limited to only working on a specific number of vaults per year to keep the traffic disruptions to an acceptable level. Given that, development of long term plans to repair the vaults currently in fair condition is critical as they continue to deteriorate to poor and very poor condition over the next decade. The shifting of over two percent of vaults from very good to good condition over the past year is also an indicator that some vaults which only last year were in very good condition, are already starting to deteriorate. 0 Over the last year, there has also been a significant shift of Network Transformers from good to fair condition. In total, of these transformers are currently in fair condition. Replacement of these units requires very detailed planning as their replacement may need to happen in conjunction with network vault rebuilds or cable replacement. During this time a network may be running under contingency for extended amounts of time while the improvement work is executed. This may require that other projects designed to increase the load capacity or contingency capability of the network be executed before actual transformer replacements. However, as the condition of these units deteriorates, plans should be made to maximize economies of scale in the replacement of other network components, in addition to the select transformers. The ATS grouping has continued to see asset condition degradation to the point where over percent of the asset class is now in poor or very poor condition. This amounts to eight units in very poor condition and in poor condition. Given the extremely high impact of failure of network electrical components, the units in very poor condition

17 EB-0-0 Exhibit D Page of 0 should be replaced within the next year as the probability for failure is high. The units in poor condition should be scheduled for replacement as soon as practicable, given the high impact that a failure could create. The shifting of condition for this asset class to poor and very poor has resulted in a reduction of the number of units in fair condition; this now stands at eight. Long-term plans should be developed to phase out these units over the next number of years as they degrade to poor and very poor condition. Given the obsolescence of these components due to their age, it may be beneficial to replace some of the units in conjunction with other network projects such as vault rebuilds or transformer replacements. This will help to gain efficiencies in terms of project planning, scheduling and coordination between groups within and external to THESL. Overhead Assets The Health Index Calculator computes health indices for the following critical overhead assets: Wood Poles Phase Overhead Gang (Rem.) Switches Phase Overhead Gang (Man.) Switches SCADAMATE 0 After continuing the migration of wood pole inspection data to Ellipse so that health index scores can be calculated, a slight decrease can be seen in the percentage of population in fair condition. This reduction of units in fair condition actually shifted to an increase in the percentage of population in poor and very poor condition. Currently over percent of the population of wood poles are either in poor or very poor condition. Though this percentage may seem small, one must take into account the fact that the population itself is very large at 0,0 wood poles. This brings the number of poles in very poor condition to, and the number of poles in poor condition to,. In addition to these poles, almost 0 percent of the population is listed as fair condition

18 EB-0-0 Exhibit D Page of amounting to, poles. The replacement of, poles over the next three years together with developing long-term plans to replace over,000 poles over the next ten years presents a significant challenge for THESL. In addition to all other civil work being completed by THESL, such as cable duct bank, pad and vault installations, pole replacements will create an extremely large volume of permits that will need to be acquired before construction can begin. This has the potential to limit THESL s ability to maximize efficiencies that can be gained by the replacement of all poles close to end-oflife that are along the same street as opposed to spot replacement of only the poles in the worst conditions. 0 0 Though pole condition itself is a major factor in the decision to replace a pole, other factors such as the condition or obsolescence of attachments, or other work required in the area, may also be taken into account. For example, it may not make sense to rehabilitate a single pole that still has porcelain insulators and is near its end-of-life to accommodate a new tree-proof conductor when it is on a street where all other poles are at end-of-life. The risks of failing to replace that pole along with all the others may be much greater than the potential savings from deferring its replacement to a later date. In this example, the outage that could result from the failure of that pole would negate all of the effort expended to replace the other end-of-life poles as the customers would still experience a power interruption. Overhead ganged switches, both manual and remotely operated, are used within the distribution system to isolate faulted sections of the feeder. They are connected to the trunk of the feeder and actuate all three phases simultaneously to either isolate or restore power to a section of the trunk. Given the potential impact to thousands of customers in the event of a switch malfunction, routine maintenance and testing of these switches is performed to ensure seamless operation, if and when required in the future. Currently none of these switches are in poor or very poor condition; however, nearly percent of

19 EB-0-0 Exhibit D Page of 0 0 all manually and remotely operated overhead gang switches are in fair condition. This amounts to units which are likely to degrade into poor and very poor condition over the next ten years. Given the reliability impact of a switch failure, long-term plans should be made to phase out these switches as they degrade into poor and very poor condition. If these long-term plans incorporate replacing these end-of-life switches with automated ones capable of inclusion in feeder automation, great improvements to overall system reliability may be achieved. SCADAMATE switches differ from remotely operated overhead gang switches in that they have the capability to be included in automatic restoration schemes; this is commonly referred to as feeder automation. Feeder automation allows for teams of switches to automatically isolate faulted sections of the system and maximize the load restored within one minute of a fault occurring. These switches have great potential for improving system reliability and as such are a critical component for the modernization of the grid. Currently there are two switches in poor condition which should be replaced as soon as practicable and ten switches in fair condition which may degrade into poor and very poor condition over the next ten years. Overall percent of SCADAMATE switches are either in good or very good condition. Given the reliability improvement potential of these switches, efforts should be made to ensure the continued good health of this asset class. Underground Assets Critical underground assets which the Health Index Calculator computes health indices for are: Vault Transformers Pad-mounted Transformers Submersible Transformers Pad-mounted Switches

20 EB-0-0 Exhibit D Page 0 of Cable Chambers Underground Cables (Direct-Buried XLPE) 0 The vault transformers asset class has seen a slight shift from very good to good, and from fair to poor condition over the last year. Currently there are vault transformers listed in poor condition. These should be replaced as soon as practicable as they are likely to degrade to very poor condition over the next three years. Though the percentage of this asset class in fair condition is only slightly over percent, due to the large population this amounts to,0 vault transformers which may degrade to poor and very poor condition over the next ten years. Replacement of these transformers will be a challenge to THESL as these transformers are often the only source of power for the buildings in which they are located. Long duration outages will need to be scheduled on a customer by customer basis over the next ten years to address all units currently in fair condition. For some customers who operate on a / basis, alternative solutions to power outages may need to be found, such as supplying temporary backup generators to maintain power while the vault transformers are being replaced. Having to supply and fuel a generator for the customer will increase the overall cost of the transformer replacement. 0 The vast majority of pad-mounted transformers are in good or very good condition; however over the last year there has been a significant shift from very good to good condition and a slight increase was also seen in the percentage of units in fair condition. There are currently units in fair condition which need to have long term plans in place for replacement over the next ten years as they degrade to poor and very poor condition. Despite the large volume of new submersible transformers being installed in the system, dramatic shifts are still taking place from very good to good condition. There is currently only one unit listed in poor condition and 0 units in fair condition. The standardization

21 EB-0-0 Exhibit D Page of and reliability improvement programs to replace non-switchable transformers with standard switchable ones is helping to keep the number of units in poor and very poor condition at a minimum; however, despite this, submersible transformers continue to be a contributing factor to underground reliability issues. Efforts will be made to improve the inspection process and asset health calculation so that the ACA more truly reflects the reliability performance of this asset class. Notwithstanding these actions, long-term plans are still needed over the next ten years to replace the units currently in fair condition as they degrade to poor and very poor condition. 0 0 A significant number of pad-mounted switches have shifted from very good to good condition over the last year. There has also been a large shift from fair to good condition, due in part to the increase in maintenance activities on this asset, such as more frequent infra-red inspections as well as more frequent cleanings. Despite these improved maintenance practices, some units have shifted from fair to poor condition. Currently there are five units in poor condition that need to be replaced as soon as practicable. Padmounted switches are connected to the trunk of underground feeders and serve the same purpose as overhead gang switches do for overhead feeders; they isolate and restore power to sections of the feeder by operating all three phases simultaneously. Isolation of these pad-mounted switches can be very time consuming as they may feed multiple distribution sub-loops. Careful planning of switching order and feeder contingency operation is required before replacement can take place. A particular challenge for THESL will be in addressing the units currently in fair condition. Long-term plans for phasing out these units as they degrade over the next ten years are required. Cable chambers, typically located near roadways, may cause significant traffic disruption during their repair or replacement. Currently there are units listed in very poor condition and in poor condition. These units must be addressed in the very near future. In addition, the cable chambers currently in fair condition are a significant

22 EB-0-0 Exhibit D Page of part of the total population. Similar to network vaults, long-term plans must be in place to address these cable chambers as they deteriorate into poor and very poor condition over the next decade. 0 Direct-buried XLPE cable has seen very significant deterioration into the very poor category over the last year. Almost 0 percent (kilometres) of direct-buried XLPE cable is rated as very poor. Despite the fact that significant capital has been invested to remove this direct-buried cable from the system, the number of faults in 00 from primary cables and splices remains the same as it was in 00. At this point, less than seven percent of direct-buried cable in the system is in very good or good condition, while over percent of these cables are in fair, poor or very poor condition. Essentially, all direct-buried cable will need to be replaced within the system over the next ten years with over half of that cable currently at the highest risk of failure and therefore having the highest probability of negatively impacting reliability. Without replacement, reliability impacts will continue to increase as the remaining direct-buried cable in the system deteriorates. 0 Conclusions THESL s Asset Management Program has improved between 00 and 0 in the following ways: Efforts have been made to consolidate asset information as Wood Pole data continue to be migrated into Ellipse. All Health Index calculations are now computed by a single tool which is accessible to everyone in the organization. This not only improves the ACA itself, but the degree to which it is utilized by THESL as an organization in planning asset renewal and replacement.

23 EB-0-0 Exhibit D Page of By focusing on last inspection data, the Health Index Calculator is helping to drive improvements in overall data quality by identifying assets with incomplete inspection records within hours of data entry. Over half of the asset categories showed an increase in the number of assets that had sufficient data to calculate a Health Index. Efforts are underway to implement newer formulations of the Health Index for certain asset classes as recommended by Kinectrics.