Quality of service improvement opportunities with advanced capacitor controls

Opportunities to improve the quality of service to electric system customers by introducing advanced control relays for switched capacitor banks are discussed. The major emphasis is on substation applications, although distribution system applications are also discussed. The developmental background, measurement techniques, control features, and several specific applications of the control relay are described. The control relay responds to the actual measured power factor with voltage override and load current-following capability, which allows it to respond differently during light and heavy load conditions. The control has optional time-of-day and day-of-week voltage biasing capability. Use of additional control inputs such as a temperature override function to allow the switching of capacitor banks in anticipation of weather related load is also described