1. Palmer House Hilton – Private Dining Room 9
A Comparable Method for Benchmarking the Reliability Performance of Electric Utilities
Dan Kowalewski
IEEE PES 2002 Summer Meeting
Chicago, Illinois
Palmer House Hilton – Private Dining Room 9
Monday, July 22, 2002 – 2:00 to 5:00 PM

2. Overview Criteria and Desired Elements Analysis Conclusions Approach
Alternatives Considered
Proposed Application Rules
Calculation Specifics
Analysis Results
Conclusions

3. Event Criteria Create Event Exclusion Criteria
Facilitates Consistent Exclusions
Allows “Fair” Benchmarking
Provides Information to Understand Performance Trends
Repeatability of Results

4. Desired Elements Has Clear Rules for Application and Exclusion
Removes Subjectivity
Scales to Various Sized Utilities
Removes Outlying Events
Removes Major Weather Variability
Allows Trends to Appear
Balances Operational Concerns
Frequency
Duration
Allows for Consistent Results
Ease of Calculation

5. Analysis: Approach Compare Proposed Methods to Understand
Consistency and Understandability
Differences of Exclusions
Impacts on Different Sized Companies
Variability of Results
A Great Deal of Confusion Initially
Methodology and Calculation Approach was Not Clear
3 Years vs 5 Years of Historic Data
Log vs Non-Log Data
Basis Unclear: SAIDI, SAIFI, Customer Minutes
Had to Apply Data to Understand
Traded Methodology and Results
Ensures Consistent Application
Expanded Understanding with Broader Data Set

6. Analysis: Alternatives Considered
Traditional 10% IEEE Definition
ComEd Region
ComEd
PECO
Bootstrap
3 Year Historic
5 Year Historic
2.5 or 3 Beta (SAIDI per Day)
6 Beta (SAIDI per Day)
Other Analysis
SAIDI per Calendar Day
Start Time of Interruption
Customer Interruption Minutes Experienced per Day
Rolling 24 Hour Window

7. Alternative Comparison
Removes Weather Variability
Clear Rules for Exclusion
Removes Subjectivity
Removes Outliers
Balances Frequency
Balances Duration
Ease of Calculation
Allows Trending
Scalability

8. ComEd Major Event Days * * * * * * * Based On Outage Start Date
* * Customer Interruption Minutes by Calendar Day
* * * Based on 24 hour rolling customer outages

9. * Based On Outage Start Date
ComEd Major Event Days *
* Based On Outage Start Date

10. 3 Beta SAIDI Day -Threshold Calculation
IEEE data (all outages > 5minutes)
Five years of most recent historic SAIDI per day data
Take the log of SAIDI per day values
Calculate the mean
Calculate the population standard deviation
Calculate the mean plus 3 times the standard deviation
Convert back to SAIDI per day values by taking the exponential of the calculated mean plus 3 times the standard deviation number
Results in a Threshold Exclusion value
Threshold value is applied to the year following the five-year data analysis period
All days with SAIDI greater than or equal to the calculated Threshold value are considered Major Event Days

11. Thresholds of Daily SAIDI (3 Year Rolling)

12. Thresholds of Daily SAIDI (5 Year Rolling)

13. Variability of Thresholds

14. PECO - Variability of Thresholds
Bootstrap
3 Beta
3 Beta
Bootstrap
Bootstrap Thresholds can be highly volatile, especially with few years of data (the saturation effect).

15. ComEd Daily SAIDI ( )

16. ComEd Daily SAIDI ( )

17. ComEd Daily SAIDI ( )

18. Conclusions Recommend 3 Beta SAIDI per Day Achieves Objectives
Consistent
Facilitates Fair Benchmarking
Provides Information to Understand Performance Trends
Repeatability of Results
Proven with REAL Data