3-PHASE COMPENSATOR FOR LOAD BALANCING AND REACTIVE POWER COMPENSATION IN 3-PHASE, 4-WIRE ELECTRIC-POWER DISTRIBUTION-SYSTEMS

This paper deals with a three-phase active power compensator (APC) to compensate reactive power and to balance unbalanced loads in the three -phase four-wire electric power distribution system. An APC is realize d employing three single phase IGBT based VST bridges with a common de bus capacitor. Reference supply currents are estimated using P-I cont rol over the average de bus voltage and three phase supply voltages. A PC reference currents are derived from reference supply currents and l oad currents. A hysteresis rule based carrierless PWM current control is used over compensating currents of the APC and its derived referenc e currents. Simulated performance of the APC for the single phase, two -phase and three-phase lagging power-factor loads is illustrated to de monstrate the reactive power compensation and load balancing features of the APC.