NERC / TVA STABILITY WORKSHOP CHATTANOOGA, TN MAY 23-24, 24, 2007 Robert Dintelman Utility System Efficiencies, Inc.
WECC Transmission System
1996 Western Outages July 2, 1996 July 3, 1996 August 10, 1996
Causes/Contributing Factors Initiating Outages Caused by Vegetation in Transmission Right of Way Relay Misoperations
Causes/Contributing Factors Inaccurate system models both load and generation Operating in unstudied system conditions
Causes/Contributing Factors Voltage Collapse Issues Lack of situational awareness of system operators and/or failure of system operators to act decisively to avoid wide-spread outages
Effects of the Outages July 2, 1996 5 Islands Formed 2.25 Million Customers Up to 6 Hours for Restoration August 10, 1996 4 Islands Formed 7.49 Million Customers Up to 9 Hours for Restoration
Formed Operating Capability Study Group to implement procedures and operating Nomograms. Implemented Policy Don t t Operate under Conditions that Have Not Been Studied. Developed and Implemented Minimum Reactive Reserve Margin Criteria and Voltage Collapse Methodology.
Implemented Recommendations from NERC Publication on Voltage Collapse Phenomenon UVLS Schemes Implemented. Initiated Annual Surveys to Identify Voltage Stability Problems. Coordinated and Implemented UFLS Program for Entire Interconnection Very Comprehensive Study.
Power System Stabilizers Properly Tuned In Service when Generator On Line Automatic Voltage Regulators In Service when Generator On Line Operating in Voltage Control Mode
Formed Operating Transfer Capability Policy Committee Approve Critical Transfer Limits before each Operating Season Approve Operating Procedures Each Season Implemented Generator Testing Program Units Stay on Line when Needed Achieve Needed Accuracy of Study results Steady State and Dynamic Reactive Capability
Enhanced Operator Training Programs Unusual or Stressed Operating Conditions Improved Communication and Coordination Across Areas Timely Reporting of Key Facility Outages Timely Actions to Preserve Reliability System Operator Certification Programs Implemented.
Implemented Controlled Islanding Schemes. Implemented Policies to Address Relay and SPS Misoperations. Developed and Implemented. Disturbance Monitoring Program
Implemented Policies for Timely Follow-up of Disturbance Recommendations. Implemented Three Reliability Centers to Monitor Overall System Operation and Direct Action as Needed. Addressed Vegetation Management Conduct Quarterly Survey
Implemented Reliability Management System to Enforce Compliance through Monetary Sanctions Enforcing: Transfer Capability Operating Reserve Control Performance PSS and AVR
Enforcing (continued): Certification of Relay Applications Certification of SPS Applications Relay Misoperations SPS Misoperations Communicating Operating Limits Operator Certification Tagging
Enforcing (continued): Transmission Line Loading Relief Transmission Maintenance
Closing Thoughts These blackouts have provided us with tremendous lessons learned. Let s s not forget the lessons as time goes by and let s s continue to work together to increase awareness throughout our industry.