Automated Capacitor Control Program at TXU Electric Delivery SWEDE May 1, 2006

2 Automated Capacitor Control Program Why capacitor automation? TXU ED’s capacitor automation system requirements System architecture System implementation considerations

3 Why Capacitor Automation ? Capital savings on future capacitor additions Reduced O&M costs Manpower savings Improved utilization of assets Ability to adapt to changing system needs Compensate for customer supplied capacitors Easier to make control setting changes Increased availability of information on capacitor bank status and operation Information available in a timely manner System reliability and losses

4 TXU ED’s Capacitor Automation System Requirements Centralized control Support multiple communications modes Control logic based on VAR flow limits using existing substation feeder/bank information (watts, VAR, voltage) Provide centralized control for Non-LTC stations (voltage control primary - VAR secondary) Identify specific banks requiring maintenance Provide information on the availability of capacitors Identify feeders with excess or deficiencies of capacitors at peak conditions Backup local control logic

5 System Architecture PI Database Yukon Workstation Paging Company 1 Paging Company 2 Central Database Feeder Breaker Watts & Vars CBC 7010

6 System Implementation Considerations Field trial – size and time frame Inform all groups effected by the project to gain support and get feedback System implementation time schedule - allow for issues identified during initial stages on project Manpower requirements for installation of controls and setup of central system (excellent OJT opportunity for system operators) Project implementation procedures which verify and document proper operation of all system components Field installations  Minor repairs identified during control installation  Who will perform control installations?  Detailed installation and documentation procedures Provide adequate training for installers and emphasize need to follow procedures

7 System Implementation Considerations (cont’d) Manpower shift with centralized control Who will run the system? Manpower requirements for day to day operation Maintenance procedures for banks identified by system in need of maintenance Contingency plans if central system goes down Changes in inspection cycles Reports to management

8 QUESTIONS?