Reasons for benchmarking voltage sag performance

1. Calculating System Events and Using Voltage Sag Benchmarking as a System Performance Indicator – What are utilities doing?

2. Reasons for benchmarking voltage sag performance • Basis for evaluating ongoing system performance (based on events that impact customers – more than traditional reliability) • Basis for evaluating economics of power quality improvement options • Basis for implementing PQ-based contracts • Basis for attracting customers that are concerned about PQ levels • Can be basis for standards

3. Important Concept - Aggregation • Measurement aggregation • multiple phases or channels per measurement • Temporal Aggregation • breaker reclosing • Spatial Aggregation (system events) • multiple monitors per location

4. San Diego Gas & Electric? • Monthly reports on SARFI rates and power factor are distributed to power quality engineers, distribution engineers, grid operation engineers, and some customer reps. • The cause of every voltage sag below 0.90 per unit is tracked for periodic review. • Monitoring at over forty substation and customer locations

5. Baltimore Gas and Electric • In March 1996, BGE began a monitoring project at the substation busses of 40 distribution feeders. • Over three years of power quality disturbances and steady state samples collected to date constitute a five gigabyte database. • BGE has looked into using SARFI indices as a factor for determining where to allocate planning and maintenance dollars. • In June 1997, BGE placed an advertisement in their regional edition of the Wall Street Journal that quoted SARFI statistics.

6. THE WALL STREET JOURNAL, TUESDAY, JUNE 17, 1997 To assure quality and price, BGE’s power passes through this line first. For a special team of BGE experts, their most important job is keeping your business up and running. BGE’s dedicated Power Quality Team evaluates customer needs to improve your business operations. They do power quality metering. Visual and thermovision inspections. System evaluations. Substation reconfiguration. And more. That’s why BGE’s power quality is almost a third better — 27.7% fewer voltage sags — than the 24 other utilities studied by the Electric Power Research Institute. And we provide this extra power quality service while holding the line on electric rates. It all addsup to greater energy valuefor you and your business. www.bge.com

7. United Illuminating CompanyNew Haven, Connecticut • UI employs about 40 power quality monitoring instruments to monitor every bulk power substation and many key customers. • SARFI rates are computed regularly and tracked to determine where problem areas are in system. • Key customers have been presented monitoring and SARFI data when questions arise on whether UI is providing sub par power. • UI published its annual SARFI rates in an Edison Electric Institute journal article.

8. -SARFI70 =7.075 Faults on Own Feeder 12.03% Faults on Transmission System 31.54% Faults on Parallel Feeders 56.43% UI Example - Voltage Sags to 70% or Less Including Feeder Outages - 1998

9. UI Example – Using SARFI-70 to track individual substation performance

10. Detroit Edison Company • Detroit Edison’s monitoring system includes over 136 monitors for the purpose of administering its contracts at 58 locations operated by Ford Motor Company, General Motors Corporation, and DaimlerChrysler. • The contracts require payments when excessive numbers of interruptions and/or voltage sags are tallied during a calendar year, using a “sag score” to track the payments.

11. Example Sag Score Report from PQView

12. PowerGrid (Singapore) • Continuous benchmarking of voltage sag performance due to importance of semiconductor industry customers. • Developed to concept of a SARFI Map to characterize the different expected voltage sag performance characteristics for different parts of their system.

13. SARFI Map

14. Integrated Monitoring System (e.g. PQView and PQWeb)