Fuzzy logic based automatic capacitor switching for reactive power compensation

To cope with the growth of load demand, it is known that one of the power utilities in Hong Kong tried to implement an automatic scheme for capacitor switching. However, due to the frequent switching which occurred, resulting in hunting, and the difficulty in determining suitable ON/OFF settings, the scheme was unsuccessful. The authors propose a pragmatic design of a capacitor switching controller which has been successfully tested. Besides power factor, the control signal also incorporates MVAr and the advantages are highlighted. To improve the reliability and robustness of the system, fuzzy logic has been introduced. The performance is described based on both the conventional step control and the continuous TCR/TSC (thyristor controlled reactor/thyristor switched capacitor) control.