critical issues – standardization · pdf file1 critical issues – standardization...

Toronto Hydro-Electric System Limited EB-2011-0144

Exhibit D1 Tab 10

Schedule 1 ORIGINAL of 34

CRITICAL ISSUES – STANDARDIZATION PORTFOLIO 1

2

THESL plans, designs and constructs distribution system assets, in accordance with 3

approved standards. The standards are intended to ensure that the distribution system is 4

safe and reliable in accordance with Ontario Regulation 22/04, which requires that 5

electrical distribution be built to the approved standard at the time of construction. 6

Standard designs also facilitate harmonization of inventory items, operating procedures 7

and maintenance procedures. 8

9

There are assets in service that were installed prior to the development and adoption of 10

the standards currently in use. These legacy installations were put into service prior to 11

amalgamation of the former utilities of Toronto Hydro, Etobicoke Hydro, North York 12

Hydro, Scarborough PUC, East York Hydro and York. THESL began work to 13

standardize transformer and SCADAMATE equipment in 2010 and continues that work 14

in 2011. THESL plans to continue standardization work in 2012-2014, to replace 15

completely self-protected (“CSP”) transformers and manual switches. Where it is 16

efficient to do so, CSP transformers and manual switches will be replaced as part of 17

other overhead capital work. Going-forward, THESL intends to integrate standardization 18

work into regular operational work for rebuild projects identified under the overhead 19

capital portfolio. 20

21

The Standardization Portfolio also includes plans for upgrading and replacing distribution 22

system components and legacy assets that are obsolete or considered inadequate for the 23

present purpose. Assets that have been identified for consideration under this portfolio 24

include: 25

• SCADAMATE R1 switches 26

• Transformer grounding components, and 27

• Standoff brackets and various overhead porcelain equipment 28


Exhibit D1 Tab 10


Given that the majority of these components have associated safety issues, system-wide 1

replacement programs have been established. Similar to the CSP transformers and 2

SCADAMATE standardization programs, where it is efficient, these assets will be 3

replaced as part of underground and overhead rebuild. 4

5

Table 1 below shows the number of specific assets planned to be replaced within the 6

Standardization Portfolio over the 2012-2014 test years. Table 2 presents the actual, 7

bridge and test year spending associated with this work. 8

9

Table 1: Planned Investment Schedule 10

2012 2013 2014

Completely Self-Protected (CSP)

Transformers 300 120 -

Manual Switch Replacements 110 55 -

SCADAMATE R1 Switches - 20 25

Grounding Compliance - 1,133 1,133

Porcelain Insulators - 400 400

Porcelain In-Line Switches - 20 25

Porcelain Pothead Terminations - 50 63

Standoff Bracket Replacements - 343 -

TOTAL 410 2,141 1,646


Exhibit D1 Tab 10


Table 2: Standardization Capital Summary ($ millions) 1

2008

Actual

2009

Actual

2010

Actual

2011

Bridge

2012

Test

2013

Test

2014

Test

Standardization - 5.7 30.2 21.7 9.1 10.3 6.1

Capital spending in 2010 funded the work required to support contact voltage 2

remediation efforts and upgrades of distribution assets supporting the streetlighting 3

system. Replacement of non-standard transformers, PMH switchgear installations, 4

SCADAMATE switches and overhead fuses was also included in the 2010 actual 5

spending. The $8.5 million reduction in the bridge year was due primarily to the re-6

classification of follow-up work associated with the handwell replacement program to the 7

Secondary Upgrades Portfolio. 8

9

The 2012 test year spending is focused primarily on CSP transformers and manual 10

switches. Contact voltage remediation work which made up a large portion of the 2011 11

spending was completed in 2011. Average unit costs for CSP transformers, and 12

standardizing manual switches, is expected to be $22,000, and $18,000, respectively. 13

14

Several multi-year standardization programs are planned for 2013, with expected capital 15

spending of $10.3 million. Transformer grounding compliance and porcelain insulator 16

replacements are estimated to cost $2.2 million and $520,000 annually, respectively, for 17

the planned number of units shown in Table 1. Replacement of SCADAMATE R1 18

switches, porcelain potheads and in-line switches is labour-intensive. THESL estimates 19

that the average unit costs for this work are about $60,000, $22,000 and $6,000, 20

respectively. For 2014, the decrease in capital spending of $4.2 million is due mainly to 21

the planned transition of CSP transformers and manual switch replacements into the 22

overhead capital portfolio. 23


Exhibit D1 Tab 10


CSP Transformers 1

CSP transformers are an obsolete transformer-type. These transformers contain fusing 2

inside the transformer tank and they are typically mounted on 35-feet poles. In 3

comparison, the current standard for overhead, pole-mounted transformers requires the 4

fuse to be externally-located, and that transformers be installed on taller poles. CSP 5

transformers are located mainly in north-central Toronto with a smaller percentage of 6

them located in the former distribution service areas of Etobicoke and Scarborough. 7

There are currently about 2,200 CSP transformers and a map of their locations is shown 8

below in Figure 1. 9

Figure 1: Map of CSP Transformer Locations 10

11

CSP transformer fuses cannot be replaced in situ. When they operate under fault 12

conditions, crews must replace the entire unit which extends the duration of the 13

associated outage. This type of transformer is being replaced on the worst performing 14

feeders mentioned in Exhibit D1, Tab 10, Schedule 32. 15


Exhibit D1 Tab 10


THESL plans to replace 1,275 CSP transformers as part of its work on the worst 1

performing feeders overhead rebuilds over the test years. An additional 420 CSP 2

transformers will be replaced within the Standardization Portfolio which in total accounts 3

for about 45 percent of the CSP transformers population. 4

5

Manual Switch Replacements 6

The SCADAMATE standardization program continues in the test years with the 7

replacement of manual loadbreak switches for added operational flexibility and increased 8

reliability. SCADAMATE switches allow THESL to better manage service interruptions 9

under outage events. There are about 1,280 three-phase manual switches whose locations 10

are shown in Figure 2. 11

12

Manual switches at feeder ties will also be replaced with SCADAMATE switches. 13

Station areas that are targeted for this work include Fairbanks TS, Bathurst TS, Horner 14

TS, Manby TS, Cavanagh TS, Malvern TS and Scarborough TS. Manual switch 15

replacements within the Standardization Portfolio focus on supplementing and bridging 16

these 27.6kV areas. The intent is to extend outwards from stations and continue 17

expanding the automation scheme, where appropriate and feasible. 18


Exhibit D1 Tab 10


Figure 2: Map of Three-Phase Manual Switch Locations 1

2

The feeder automation program addresses about 23 percent of the manual loadbreak 3

switches over the three test years. Based on the planned investment schedule listed in 4

Table 1, THESL plans to replace 165 three-phase manual, loadbreak switches 5

representing around 17 percent of the total population. 6

7

SCADAMATE R1 (“R1”) Switches 8

THESL intends to replace R1 units manufactured from S&C Electric with the newer, 9

SCADAMATE R2 models over the test years due to operational and safety concerns 10

arising from the corrosion of the motor units. Approximately 260 locations have been 11

identified where the R1 units have been installed. A map of these locations is shown in 12

Figure 3, along with major arterial highways shown in blue. In general, the population of 13

the R1 units is on average, approximately 15 years old based on the manufacturing date. 14

THESL plans to leverage on the existing insulator washing program and target select R1 15

locations in the former distribution service areas of Etobicoke and North York, before 16

addressing the remaining R1 locations in these areas, and then proceeding to other 17


Exhibit D1 Tab 10


concentrated areas of R1units across the rest of Toronto. Approximately 45 units are 1

planned for replacement over the three-year test period representing approximately 20 2

percent of the R1 population. 3

Figure 3: Map of SCADAMATE R1 Switch Locations 4

5

6

Grounding 7

A number of grounding improvements are required to bring existing installations up to 8

currently approved construction standards. Specifically, some submersible transformer 9

vaults and pole-mounted transformers are not adequately grounded. Figures 4 and 5 10

show the submersible vault and overhead pole locations targeted for grounding 11

improvements. 12

13

Residential, open-loop 13.8kV and 27.6kV single-phase submersible transformers in the 14

horseshoe area will be subject to this retrofit; in particular one of the main areas of focus 15

will be in the former distribution service area of Scarborough. In addition, pole-mounted 16

transformer grounding issues have been identified within the downtown core on older 17


Exhibit D1 Tab 10


4kV and box construction designs. The populations of submersible and overhead pole 1

locations that require grounding system improvements are approximately 8,000 and 2

8,900, respectively. It is estimated that 2,266 vault and pole locations will need to be 3

rebuilt over the test period through the Standardization Portfolio, which accounts for 4

about 13 percent of the total population requiring improvement. 5

Figure 4: Map of Targeted Submersible Vault Locations for Grounding 6


Exhibit D1 Tab 10


Figure 5: Map of Targeted Overhead Locations for Grounding 1

2

Grounding compliance is essential to ensure the safe and proper operation of distribution 3

system equipment. It involves electrically bonding all non-current carrying conductive 4

components together and establishing a sufficiently low resistance path to the earth. This 5

limits system voltages in fault conditions, ensures that fuses and circuit breakers operate 6

properly and protects workers and the public from potentially dangerous step and touch 7

potentials, in the event of a fault. 8

9

Porcelain Insulators 10

Historically, porcelain has been the material of choice for electrical distribution pole line 11

hardware such as insulators with an example shown below in Figure 6. As porcelain 12

insulators are exposed to environmental conditions and become contaminated, a lower 13

resistance path forms across the insulator that eventually allows for a voltage discharge, 14

or arc to ground. Ultimately, this leads to a semi-conductive track that, over time, further 15

weakens the insulator. There are approximately 162,300 porcelain insulators in the 16

overhead distribution system located across all of the former distribution service areas 17

and a map of these locations is presented in Figure 7. 18


Exhibit D1 Tab 10

Schedule 1 ORIGINAL

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Figure 6: Typical Porcelain Insulator 1

Figure 7: Map of Overhead Insulator Locations Along Various Conductors 2


Exhibit D1 Tab 10

Schedule 1 ORIGINAL

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Porcelain insulators are a known reliability concern. They are a major CI contributor to 1

defective overhead equipment, as shown in Exhibit D1, Tab 7, Schedule 3. THESL will 2

be focusing on replacing porcelain insulators on WPF feeders, other areas deemed to be 3

under-performing, older system configurations such as box construction, and congested, 4

heavily treed areas where the potential for failure is high and there may be associated 5

public safety risks. 6

7

There are approximately 8,200 locations with porcelain insulators that will not be 8

addressed through other overhead capital rebuilds during the test period. Approximately 9

800 of these locations, or ten percent, are planned for replacement in the Standardization 10

Portfolio during the test years. 11

12

Porcelain In-Line Switches 13

Porcelain in-line switches are a legacy standard. The majority of THESL porcelain in-14

line switches are old, with an average age of 39 years. Additionally, 30 percent of the 15

porcelain switch locations are 50 years of age or older, which is considered the typical 16

life for overhead switches. In comparison, in-service polymer in-line switches have an 17

average age of 13 years with 70 percent of these switch locations less than 20 years old. 18

19

Figure 9 is a map showing inline switch locations on the overhead distribution system; 20

approximately 1200 of those locations have porcelain in-line switches. Over the test 21

years, THESL plans to replace 45 porcelain in-line switches and will be targeting 4kV 22

and 27.6 kV locations across the system that either have porcelain switches or are past 23

their typical useful life. About 15 percent of installations with the greatest potential of 24

failing are planned for replacement over the test years. 25


Exhibit D1 Tab 10

Schedule 1 ORIGINAL

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Figure 9: Map of In-line Switch Locations 1

2

Porcelain Pothead Terminations 3

Porcelain potheads are used to terminate Paper Insulated Lead Cables (“PILC”) on 4

4.16kV and 13.8kV systems and are typically located on riser poles. The pothead 5

terminations consist of a cast iron body connected to one end of a wiping sleeve and the 6

other end to a porcelain connection, or other type of termination, depending on the cable 7

type. If these types of terminations fail in a catastrophic manner, there could be public 8

safety risks associated with falling debris and oil. THESL plans to replace these assets 9

proactively and transition from PILC to Cross-Linked Polyethylene (“XLPE”) cables 10

with polymer terminations. There are approximately 565 porcelain pothead locations and 11

a map of these locations is shown below in Figure 10. The majority of porcelain 12

potheads are located in the downtown core with the remaining locations dispersed across 13

the former distribution service areas of Etobicoke and Scarborough. THESL plans to 14

replace 103 units or approximately 20 percent of the total population by first targeting 15

public thoroughfare areas such as sidewalks, bus stops and school zones over the test 16

period. 17


Exhibit D1 Tab 10

Schedule 1 ORIGINAL

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Figure 10: Map of Porcelain Pothead Terminator Locations 1

2

3

Standoff Bracket Replacements 4

Fibreglass standoff bracket replacements are used to support the insulator that carries the 5

primary tree-proof covered conductor on the pole. These brackets are installed on the 6

overhead system, and are located mainly in heavily treed and congested areas. Recently, 7

THESL has identified 343 non-compliant brackets containing 5-3/8” pins that should be 8

replaced with units containing 6” pins. THESL plans to replace these brackets in 2013. 9


Exhibit D1 Tab 10

Schedule 1 ORIGINAL

of 34

DRIVERS OF THESL’S STANDARDIZATION WORK PROGRAM 1

2

CSP Transformers 3

Outage Duration 4

Standard pole-mounted transformers have external fusing so it is relatively simple to 5

replace fuses to restore power after an outage. CSP transformers have internal fusing and 6

the entire transformer must be replaced to restore power after an outage. When fuses 7

operate on standard-pole mounted transformers, in about 50 percent of the cases, they 8

operate again when they are replaced which indicates a problem within the transformer 9

itself and the transformer is subsequently replaced. Pole-mounted transformers take 10

slightly longer to replace than CSP transformers; however, they are replaced about half as 11

many times as CSPs since fuse replacement is effective in restoring power to standard 12

pole-mounted transformers about 50 percent of the time. Table 3 shows the improvement 13

in outage duration associated with the replacement of CSPs with standard pole-mounted 14

transformers. 15

16

Table 3: Outage Duration Impact of Standard Installations versus CSP 17

Installations 18

Standard Installation CSP Installation Standardization

Improvement

Minutes Out Due to

Blown Fuse (Typical) 15(0.5) + 195(0.5) = 1051 180 42%

Note: 1The value of 105 minutes is based on a typical replacement time of 15 minutes for the

external fuse and 195 minutes for the replacement of both the transformer unit and fuse.

Frequency of Transformer Failures 19

Figures 11, 12, and 13 show that the number of CSP transformer related outages and the 20

associated impacts on CI and CHI have been considerably higher than those related to 21

standard pole-mounted transformers for the past five years. The year-over-year 22


Exhibit D1 Tab 10

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percentage change in CI and CHI from 2009 to 2010 for CSP transformers was 34 1

percent, and 108 percent, respectively. In contrast, between 2009 and 2010, the percent 2

change in CI due to defective standard pole-mounted transformers decreased by 86 3

percent and the change in CHI increased marginally by 13 percent. 4

Figure 11: Summary of CI Due to Defective Overhead Transformers 5


Exhibit D1 Tab 10

Schedule 1 ORIGINAL

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Figure 12: Summary of CHI Due to Defective Overhead Transformers 1

Figure 13: Summary of Outages Due to Defective Overhead Transformers 2


Exhibit D1 Tab 10

Schedule 1 ORIGINAL

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2

Manual Loadbreak Switch Reliability 3

Exhibit D1, Tab 7, Schedule 3 shows the contribution overhead switches make to CI and 4

CHI. With the exception of 2008, CI and CHI have increased 15 percent, and 50 percent, 5

over 2006 levels, respectively, due to failure of overhead switches. Figures 14 and 15 6

show that although CI and CHI contributions from manual loadbreak switches have 7

remained fairly consistent over the last five years with an average of 19,410 and 7,340, 8

respectively, they account for about 29 percent of the CI contribution and 25 percent of 9

the CHI contribution of all overhead defective switches. 10

11

Manual loadbreak switches represent about five percent of the total loadbreak switch 12

population. However, Figure 16 shows that over the past five years, 69 outages, or about 13

20 percent of the total number of outages resulting from defective switches over that 14

period, have been attributed to the failure of manual loadbreak switches. 15

Figure 14: CI Comparison of Manual Loadbreak and Total Defective Switches 16


Exhibit D1 Tab 10

Schedule 1 ORIGINAL

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Figure 15: CHI Comparison of Manual Loadbreak and Total Defective Switches 1

Figure 16: Outage Comparison of Manual Loadbreak and Total Defective Switches 2


Exhibit D1 Tab 10

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Reliability Improvements Associated with Feeder Automation 1

Exhibit D1, Tab 9, Schedule 2, describes a feeder automation (“FA”) pilot project in 2

2010 that was successfully implemented on ten feeders. The pilot showed significant 3

reliability improvements under outage conditions, and it is anticipated that expanding to a 4

larger network of FA schemes on trunk portions of feeders would typically result in 75 5

percent of the customers being restored within one minute. Service restoration for 6

feeders without FA schemes take on average four hours, as construction staff have to 7

manually sectionalize feeders to isolate the fault and then restore service to the remainder 8

of the feeder. 9

10

SCADAMATE R1 Switches 11

12

Safety 13

Failure investigations and feedback from operating staff indicate that motor units on the 14

SCADAMATE R1 switches are susceptible to corrosion due to moisture ingress. Figure 15

17 illustrates one such example. The failure mode for these switches is a potential safety 16

concern for crews, as they have been shown to unexpectedly operate during routine 17

maintenance activities. 18

19

In 2008, THESL encountered two isolated incidents pertaining to the R1 units that were 20

targeted for maintenance and/or repair. In the first incident, operations staff had found 21

and confirmed that the switch was initially remotely opened. The crew then proceeded to 22

physically de-clutch and open the switch to view the visual open point. However, during 23

the de-clutching of the switch, the disconnection lever inadvertently closed. Unaware 24

that the switch had closed electrically, the crew worker continued to physically open the 25

manual disconnect portion of the switch. This caused a physical open point between the 26

two electrical contacts, drawing an arc and causing both breakers to open and lock out, as 27

a hold-off was in effect. This near-miss incident led to extensive damage of the switch. 28


Exhibit D1 Tab 10

Schedule 1 ORIGINAL

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Figure 17: Corrosion of SCADAMATE R1 Motor Unit 1

2

In the second incident, an R1 switch was remotely opened with the control box switch 3

indicator showing an “O” (Open) sign, and confirmed to be electrically open by 4

operations staff. The switch was then placed in the local remote position, as a current 5

check was being performed prior to manually opening the switch. Similar to the incident 6

described above, during the physical de-clutching of the switch via a disconnect 7

operating lever, the switch inadvertently closed. A crew worker then attempted to open 8

the switch both locally and remotely, but was unsuccessful. As the feeder breakers did 9

not lockout, a crew member was able to perform the necessary switching to allow safe, 10

electrical isolation of the defective switch. An attempt was made to physically open the 11

electrically de-energized switch, but the crew member was only able to open the 12

disconnect switch a few inches. Subsequently, the defective switch was replaced. 13

14

More recently, mechanical switch indicators at an R1 switch showed the switch to be 15

closed, which conflicted with SCADA readings observed by control room personnel. 16


Exhibit D1 Tab 10

Schedule 1 ORIGINAL

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Grounding 1

2

Safety 3

Submersible transformer vaults are small, underground enclosures that generally house a 4

single-phase transformers as seen in Figure 18. 5

Figure 18: Single-Phase Submersible Transformer Vault 6

7

When fault currents have no path to ground through a properly designed and maintained 8

grounding system, fault currents will find unintended paths that could present safety 9

hazards to the employees and the public. Additionally, a poor grounding system 10

increases the overall impedance of the path to ground, resulting in a potentially higher 11

than allowed (by the Ontario Electrical System Code (“OESC”) and Electrical Safety 12

Code (“ESC”)) voltage rise between parts of the station or vault and ground grid. 13

Existing submersible vaults identified for replacement require grounding upgrades to 14

bring them up to current standards, including additional ground electrodes. Figures 19 15

and 20 show the difference between a single-phase submersible transformer with one 16

ground rod, and the current THESL standard with four ground rods. 17


Exhibit D1 Tab 10

Schedule 1 ORIGINAL

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Figure 19: Single-Phase Submersible Transformer with One Ground Rod 1

Figure 20: Standard for Submersible Vault Transformer with Four Ground Rods 2


Exhibit D1 Tab 10

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Figure 21 below shows THESL’s grounding standard for overhead transformers. A 1

number of locations have been identified that require grounding improvements to bring 2

them up to standard including. Improvements include: 3

• Ground rods 4

• Transformer bonding to the system neutral 5

• Connector and wire upgrades 6

• Case or H2 grounding 7

8

A recent electrical contact investigation determined that a contributing factor to the 9

contact was a corroded aluminum connection that held the H2 primary neutral, case and 10

pole ground connections, as seen in Figure 22. The corrosion impeded conductivity on 11

the system neutral, resulting in some current flow through the pole ground that ran down 12

the length of the pole to the ground rod. In this case the ground wire had also been 13

broken as a result of earlier concrete repair to the base. 14

Figure 21: Standard for Overhead Pole-Mounted Transformer Grounding 15


Exhibit D1 Tab 10

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Finally, the pole ground was found to be in contact with a metal band that was used to 1

secure a grounded control box to the pole. At the point where the ground wire contacted 2

the banding on the pole, six of the seven strands of the ground wire were burnt, leaving 3

only a single strand remaining at a height of roughly six feet from the ground. This is 4

shown in Figure 23. 5

Figure 22: Close-up View of Corroded Transformer Overhead Connections 6


Exhibit D1 Tab 10

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Figure 23: Damaged Pole Ground at Point of Contact with Metal Band 1

2

THESL considers the integrity of the grounding system to be a very high priority and is 3

proactively addressing the matter. 4

5

Porcelain Insulators 6

7

Safety and Reliability 8

Over the last decade, porcelain has been phased out for new installations in favour of 9

polymer-based materials because of the following safety and system performance issues: 10

• Develop hairline cracks leading to failure 11

• Catastrophically failure resulting in shards of jagged debris 12

• Higher tracking, leakage current, and system losses 13

• Incompatibility with tree-proof conductors that are essential for improving feeder 14

reliability along heavily-treed areas (Feeders Experience Sustained Interruptions 15

(“FESI”) feeders, for example) 16


Exhibit D1 Tab 10

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Figure 24 shows a broken porcelain insulator. In addition to the safety concerns about 1

the shards and resulting debris, porcelain fragments can also trigger pole fires. 2

3

An asset management study was conducted by the Electrical Safety Authority (“ESA”) in 4

2010 of 40 serious incident reports (“SIRs”) from all utilities over a three-year period, for 5

installations 25 years and older. Figure 25 shows what the study indicated, i.e., “known 6

equipment weakness” included the following equipment: #6 copper solid conductor, 7

wooden insulator pins, porcelain line arresters, porcelain insulators and rotten poles. A 8

quarter of the SIRs analyzed included known equipment weakness as contributing 9

factors. 10

Figure 24: Broken Porcelain Insulator 11


Exhibit D1 Tab 10

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Figure 25: ESA SIR Data and Contributing Factors 1


Exhibit D1 Tab 10

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Porcelain In-Line Switches 1


Porcelain in-line switches are associated with similar safety and reliability concerns as 3

porcelain insulators. They are legacy materials in which tracking of dirt and debris can 4

result in equipment arcs causing the switch to fall and impact public safety. The 2010 5

ESA study revealed that “falling hazards” is the biggest factor impacting public safety. 6

In comparison, other factors such as “shocks” and “explosions” were found to impact 7

public safety 25 percent, and 23 percent, respectively. Figure 26 shows the breakdown of 8

these factors in greater detail. Over 30 percent of the porcelain switches in service at 9

THESL are either at, or beyond, the typical useful life. 10

11

A THESL construction worker recently detected a failed switch during a routine 12

switching operation. The single-phase switch had failed while restoring a normally open 13

point between 13.8kV feeders.. These particular switches are bracket-mounted and used 14

to supply and isolate equipment. The failure was found to be caused by a fracture along a 15

weak point where the porcelain mounts to the base. It was later determined that similar 16

switches can break off at various other points, as seen in Figure 27. 17


Exhibit D1 Tab 10

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Figure 26: ESA SIR Data and Factors Impacting Public Safety 1

Figure 27: Broken Porcelain In-Line Switches 2

3

4

Porcelain Pothead Terminations 5


Porcelain pothead terminations can fail in a catastrophic manner, releasing porcelain 7

shards and dispersing oil. This could lead to substantial collateral damage to other 8


Exhibit D1 Tab 10

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nearby electrical equipment and public property. In addition, the dispersion of oil from 1

the damaged terminations may result in a fire or environmental damage. 2

3

In 2009, THESL received a Public Safety Concern from the ESA as a result of a pothead 4

failure sending shards of porcelain onto the balcony of a nearby home, shattering the 5

window of the family room and causing damage to the windshield of a nearby police car. 6

The effects of the failure are seen in Figure 28. THESL replaced the failed porcelain 7

pothead with a new polymer termination shown in Figure 29. 8

Figure 28: Failure Effects of the Porcelain Pothead Terminators 9


Exhibit D1 Tab 10

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Figure 29: Replaced Porcelain Pothead Terminator 1

2

3


Safety 5

Figure 30 shows a standoff bracket with a 5/8” pin. These assemblies are sub-standard 6

and should be replaced. The pin is too short so the insulator does not fully connect to the 7

bracket and the whole assembly is compromised. These bracket assemblies do not adhere 8

to current CSA requirements and can potentially fail under heavy loading conditions that 9

could cause components to break off, and fall to the ground. 10


Exhibit D1 Tab 10

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Figure 30: Fibreglass Standoff Bracket and 18” Vertical Pin 1

2

3

CONSEQUENCES OF DEFERRING THE STANDARDIZATION WORK 4

PROGRAM 5

6

CSP Transformers 7

Reliability and Operations 8

CSP transformers will continue to fail at an increasing rate if this work is deferred. CSP 9

transformers are typically located on FESI feeders or areas with a relatively large number 10

of over-loaded or undersized transformers, and deferring this work reduces the 11

opportunity to directly impact system reliability and customer service. The poles used to 12

support CSP transformers are generally shorter than current standard pole heights used 13

for standard transformer and external fuse installations. Deferral of this work also means 14

THESL would have to continue with like-for-like replacements of these legacy assets and 15

maintain inventory for CSP transformers and associated poles. 16


Exhibit D1 Tab 10

Schedule 1 ORIGINAL

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Reliability and Customer Service 2

Feeder automation offers clear reliability and operational benefits. Deferring this work 3

would constrain THESL’s ability to improve the intelligence of its distribution system, 4

the pace of restoration, and harvest cost savings associated with control-room and other 5

remote switching as compared to crew dispatch. 6

7

SCADAMATE R1 Switches 8

Safety and Operations 9

Deferring this work would extend the time these switches are in service and prolong the 10

associated operational inefficiencies, and may increase the potential safety concerns 11

associated with them. More units would be used only for load transferring and 12

sectionalizing as operational staff may be reluctant to operate or work in proximity to 13

these switches. Consequently, for planned work, maintenance activities, and during 14

outages, construction crews could be required to travel further to locate the next available 15

operational switch. Finally, the radios in the newer SCADAMATE R2 switches are not 16

compatible with the SCADAMATE R1 switches that they replace, so feeder automation 17

is constrained. 18

19

Grounding Compliance 20

Safety 21

Proper grounding limits step and touch potentials to safe levels for THESL construction 22

staff and the public. Work in this area is a top priority. 23

24

Porcelain Insulators, Porcelain In-Line Switches, and Porcelain Potheads 25

Safety, Reliability, and Operations 26

Deferral of work in this area increases the potential risk to public and worker safety as the 27

equipment continues to age and failure rates climb. Falling debris, pole fires, and 28


Exhibit D1 Tab 10

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environmental risks are all potential risks associated with these assets. 1

2

Deferral of porcelain in-line switch replacement past the test years would create a 3

backlog with more than 50 percent of the overall porcelain switch population beyond 4

their useful life. 5

6

Porcelain potheads are legacy standards associated with PILC cables. Current work 7

practices require the use of XLPE cables with polymer terminations for most applications 8

since they are lighter, have improved electrical and thermal properties and require less 9

specialization for termination and splicing. Deferral of this work prolongs the use of 10

PILC, which has decreasing availability and requires worker specialization that cannot be 11

sustained. 12

13


Safety 15

Due to the existing length of the pin, the insulator could detach and fall off causing the 16

supported overhead primary conductor to swing freely in the air. The swing in the 17

conductor can increase the tension experienced by the adjacent insulators and can result 18

in a chain reaction of failures along the same pole line. Should this type of failure occur, 19

it could pose a serious public safety risk, and result in widespread power outages. 20

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