PREDICTING HARMONIC PROBLEMS RESULTING FROM CUSTOMER CAPACITOR ADDITIONS FOR DEMAND-SIDE MANAGEMENT

The use of capacitors to correct for poor power factor is a well-estab lished and cost-effective means of reducing demand and system losses. Utilities routinely apply capacitors on transmission and distribution systems. Additional gains may be made by installing capacitors in cust omer facilities and many utilities are encouraging such installations for demand-side management (DSM) purposes. Unfortunately, many industr ial customers have serious problems with capacitor installations becau se of interactions with harmonic distortion from plant lends. Capacito rs may cause one or more harmonic to be accentuated through resonance. The capacitors themselves may be damaged or the resulting voltage dis tortion may make it impossible to operate some process equipment. It i s often difficult to predict which capacitor installations will be tro ublesome, particularly when there are numerous capacitors and harmonic -producing loads scattered over a plant's power system. A simplified a pproach that depends on less input data is described. The method is ba sed on the voltage distortion at the main bus and tire currents in the capacitors. Two test cases are presented.