1. NERC Event Analysis Overview ERCOT ROS Meeting Austin, Texas May 15, 2006

2. 2 Committees Program Groups Subject Matter Expert Groups President & CEO President & CEO Members’ Forums Compliance & Organization Certification Compliance & Organization Certification Situation Awareness & Infrastructure Security Standards Reliability Readiness Reliability Readiness Training, Education & Operator Certification Information Technology Legal & Regulatory Finance & Accounting Reliability Assessment & Performance Analysis Future Adequacy Benchmarking Event Analysis Human Resources Administration

3. 3 Overall Scope of RAPA Programs ● Reliability Assessment – Looking Ahead  Independently assess and report on reliability and adequacy of the bulk power system ● Events Analysis and Information Exchange – Looking Back for Lessons Learned  Analyze off-normal events and disseminate “lessons learned” to improve reliability performance ● Benchmarking – How are we doing?  Develop reliability performance metrics, trends, and benchmarks – requires system measurements

4. 4 Program Scope ● Investigate large-scale outages, disturbances, and near misses  Determine root causes and lessons learned ● Identify and monitor performance to detect emerging trends and signs of decline in reliability performance ● Communicate results, trends, recommendations, and initiatives to industry

5. 5 Events Under Investigation NERC “Action List” ● Los Angeles – Sept. 12, 2005  Blackout ● Denver – February 18, 2006  Rolling Blackouts ● NYPA / Ontario – March 29, 2006  Significant Generation Trip ● ERCOT – April 17, 2006  Rolling Blackouts

6. 6 Los Angeles – Sept. 12, 2005 ● Design Alert – Generation Design  Undersized exciter power supply cables on Haynes Unit 10 – resulted in tripping of ~ 500 MW of generation  Turnkey project  Similar problems on sister units installed by same A&E firm  Review design (as built) of generators to ensure they can reach rated reactive power output

7. 7 Sample Alert

8. 8 Potential Studies for “Actions List” ● Short-term demand forecasting  Contributory to 3 disturbances in 12 months ● Generation forced outages  Weather-related  Protection / control system coordination

9. 9 Questions