substation reliability

Substation Reliability

Community Insights Conference

August 20-22, 2014

Vail, CO

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2014 Electric T&D Benchmarking

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Substation Agenda

◼ Overview Benchmarking Issues Key Findings and Trends

◼ Performance Profiles & Trends Reliability and Availability Measures

◼ 2014 Benchmarking Results Initiatives Analysis

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Overview

Key Issues in Reliability

Benchmarking Issues◼ Contribution to SAIDI, SAIFI as primary measure◼ Changed the profile last year to include Momentary, Sustained, and Total

Outage Frequency rates for Substation Equipment Failures + Protective System Failures, and remove the percent time transformers out of service measures

◼ Transmission vs. Distribution Split◼ Transformer Failures

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Substation Reliability

Statistics

◼ The impact of substation components on distribution reliability (customer interruption) statistics is of interest. These include SAIDI and SAIFI. The Substation SAIDI and SAIFI here is from causes that originate “within the substation fence”. An example of this follows: A cable failure outside the substation occurs, the protecting feeder breaker fails to trip due to a

relay mis-operation, and the back-up device trips out the substation transformer, causing an interruption to the original feeder with the cable fault, as well as 3 additional feeders on the same transformer. The outage of the feeder with the cable failure is not counted in “substation” (its cause is “distribution equipment failure”), but the outage of the other 3 feeders is counted in “substation”.

◼ Independent of customer outages, we have tabulated the % of time substation transformers are out of service, both automatic and non-automatic

◼ We are now able to show measures that relate to substation effects on Transmission Circuit outage rates using results from the Transmission Reliability survey.

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Summary and conclusions

◼ There has been little change in the initiatives to reduce frequency or duration of outages. Slight change in the list or order for “reduce frequency”

• No initiatives were listed under “Other” for “reduce frequency” Slight change in order for “reduce duration of customer outages”

◼ Distribution substation contribution to SAIDI and SAIFI increased this year over last.

◼ Transmission substation SAIDI and SAIFI top performers continue to perform well. Transmission substations are only significant for a few

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Profiles & Trends

Substation Reliability Profile

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2013YE 2012YE

Mean Q1 Q2 Q3# of Bars

Mean Q1 Q2 Q3# of Bars

Contribution to Network Reliability Substation Contribution to SAIFI 0.102 0.040 0.090 0.140 13 0.096 0.018 0.042 0.133 16

Transmission Substations - SAIFI 0.036 0.000 0.001 0.072 11 0.043 0.000 0.000 0.049 11

Distribution Substations - SAIFI 0.072 0.036 0.087 0.109 13 0.067 0.018 0.040 0.100 16

Substation Contribution to SAIDI 6.55 1.67 4.00 10.52 13 5.91 1.73 1.96 5.51 16

Transmission Substations - SAIDI 1.58 0.00 0.03 2.10 11 2.11 0.00 0.00 1.73 12

Distribution Substations - SAIDI 5.21 1.54 4.00 7.21 13 4.33 1.73 1.94 4.31 16

Substation Availability

Transformer failures per 1000 Transformers

Transmission Substations - Failures 25.78 0.00 4.05 26.37 11 26.96 0.00 8.28 32.01 10

Distribution Substations - Failures 9.07 0.00 3.43 4.59 12 9.84 0.89 4.86 7.82 14

SOF from Failed AC Sub Eq, plus Failed Prot Sys Eq <200kV

0.036 0.006 0.028 0.055 12 0.073 0.026 0.059 0.077 13

MOF from Failed AC Sub Eq, plus Failed Prot Sys Eq <200kV

0.030 0.004 0.020 0.045 10 0.019 0.007 0.015 0.030 12

TOF from Failed AC Sub Eq, plus Failed Prot Sys Eq <200kV 0.061 0.010 0.062 0.078 12 0.090 0.059 0.080 0.090 13

SOF from Failed AC Sub Eq, plus Failed Prot Sys Eq >200kV 0.041 0.000 0.029 0.052 11 0.076 0.041 0.085 0.098 10

MOF from Failed AC Sub Eq, plus Failed Prot Sys Eq >200kV 0.021 0.000 0.009 0.043 10 0.030 0.008 0.010 0.047 8

TOF from Failed AC Sub Eq, plus Failed Prot Sys Eq >200kV 0.060 0.000 0.062 0.088 11 0.101 0.084 0.093 0.137 10

T&D Substation Contribution to SAIDI

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Transmission Substations Distribution Substations

Substation Reliability Pg 6, 7Source: DR30

Distribution subs performance is not as good except for 1st quartile, transmission is worse due to high numbers from 6 companies, and all others were zero.

2013 2014

Mean 2.11 1.46

Quartile 1 0.00 0.00



2013 2014

Mean 4.33 5.07




Total Substation Contribution to SAIDI

10Substation Reliability Pg 5

Source: DR30

Total substation contribution to SAIDI stats show increased mean, similar top quartile, and significantly increased median and 3rd quartile.

2013 2014

Mean 5.91 6.33




Distribution Substation Contribution to SAIDI Trend

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The mean shows little change from 2009 to 2013. Top quartile slightly worse.

T&D Substation Contribution to SAIFI


Source: DR40

Generally the proportional contribution to total SAIFI is higher than that to total SAIDI because substation outages usually have a shorter duration than distribution caused outages (mean CAIDI for substation outages is 68 min. vs. 93 min. for all outages, excluding major events).

Mean was about equal to last year, but first and second quartile were worse.

2013 2014

Mean 0.096 0.100

Quartile 1 0.018 0.041

Quartile 2 0.042 0.090

Quartile 3 0.133 0.133

Distribution Substation Contribution to SAIFI Trend

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The mean shows little change from 2009 to 2013. Top quartile is somewhat better. Median is worse. Third quartile is virtually unchanged

Benchmarking Results

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Allocation of Substation Contribution to SAIDI


Source: SR20

On Average, the most predominant are:1. Failed Equipment2. Weather Related3. Foreign Interference4. Human Error

Allocation of Substation Contribution to SAIFI


Source: SR25

On Average, the most predominant are:1. Failed Equipment2. Weather Related3. Human Error4. Power System

Condition

Transformer Failure Rate per 1,000 Transformers

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Transmission Distribution

Substation Reliability Pg 8, 9Source: SR10, ST100, ST105

Several companies have zero rates, but a few are considerably higher. Apparently high rates in transmission are probably due to low total numbers of transformers.

2013 2014

Mean 27.0 25.78

Quartile 1 0.0 0.00

Quartile 2 8.3 4.05

Quartile 3 32.0 26.37

2013 2014

Mean 9.8 9.07

Quartile 1 0.9 0.00

Quartile 2 4.9 3.43

Quartile 3 7.8 4.59

SOF from Failed AC Sub Eq, Plus Failed Prot Sys Eq

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< 200 kV > 200 kV

Substation Reliability Pg 16, 17Source: ST120, TR25

Results are much better than last year.

2013 2014

Mean 0.073 0.0364

Quartile 1 0.026 0.0056

Quartile 2 0.059 0.0276

Quartile 3 0.077 0.0545

2013 2014

Mean 0.076 0.0408

Quartile 1 0.041 0.0000

Quartile 2 0.085 0.0286

Quartile 3 0.098 0.0519

MOF from Failed AC Sub Eq, Plus Failed Prot Sys Eq

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< 200 kV > 200 kV

Substation Reliability Pg 14, 15Source: ST120, TR35

Results were worse for <200kV, better for >200kV this year.

2013 2014

Mean 0.020 0.0299

Quartile 1 0.007 0.0036

Quartile 2 0.015 0.0200

Quartile 3 0.030 0.0454

2013 2014

Mean 0.030 0.0208

Quartile 1 0.008 0.0000

Quartile 2 0.010 0.0089

Quartile 3 0.047 0.0425

TOF from Failed AC Sub Eq, Plus Failed Prot Sys Eq

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< 200 kV > 200 kV

Substation Reliability Pg 18, 19Source: ST120, TR25, TR35

Results are much better than last year

2013 2014

Mean 0.091 0.0614

Quartile 1 0.059 0.0102

Quartile 2 0.080 0.0615

Quartile 3 0.090 0.0779

2013 2014

Mean 0.100 0.0597

Quartile 1 0.084 0.0000

Quartile 2 0.093 0.0615

Quartile 3 0.137 0.0876

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Most popular:1. Preventive maintenance2. Animal abatement3. Replace obsolete controls (last year 4)4. Root cause analysis (last year 3)5. No “Other”

Substation Reliability Pg 22Source: SR30

Most Successful Initiatives TO Reduce the Frequency of Outages to Customers (1 = Lowest, 3 = Highest)

Initiative 21 22 23 24 27 28 30 31 32 33 359 38 40 Total

Animal abatement 1 2 1 2 2 3 3 3 2 2 21

Replace obsolete controls 2 3 3 1 1 2 2 1 3 18

Preventive Maintenance 3 2 3 3 2 2 1 3 3 3 2 1 28

Root Cause Analysis 4 1 1 1 2 1 1 1 3 15

Other 0

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Initiatives to Reduce Duration of Outages to Customers Have Been the Most Successful (1 = Lowest, 3 = Highest)

Initiative 21 22 23 27 28 30 31 32 33 359 38 40 Total

Autochangeover schemes 1 2 3 2 3 1 3 3 3 21

Distribution automation 3 1 3 1 1 2 11

Relay faultlocating 2 1 1 3 1 2 3 2 15

Spare or mobile transformers 3 2 2 2 1 2 1 13

Other 1 2 3 6

Substation Reliability Pg 24Source: SR35

Most popular:1. Auto changeover Schemes (Last year 1)2. Relay Fault Locating (Last year 4) 3. Spare or Mobile Transformers (Last year 3)4. Distribution Automation (Last Year 2)5. “Other” inclluded

• Multi - shot reclosing• Redundancy in the system, SCADA

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Total reported sustained outage events from all respondents

Total Events = 118

About 21% of sustained outages are due to substation causes.

Thank you for your Input and Participation!

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First Quartile Consulting is a utility-focused consultancy providing a full range of consulting services including continuous process improvement, change management, benchmarking and more. You can count on a proven process that assesses and optimizes your resources, processes, leadership management and technology to align your business needs with your customer’s needs.

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About 1QC

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substation reliability

Documents

transmission substation

substation effects

substation fence

time substation transformers

distribution equipment

cable failure

total outage frequency

duration of outages