Combined compensation structure of an SVC and an active filter for unbalanced three phase distribution feeders with harmonic distortion

A combined reactive power compensation method of a static VAr compensator (SVC) and an active filter is described in this paper for unbalanced three-phase distribution feeders with harmonic distortion. The SVC acts as a classic reactive power compensator for load balancing and power factor correction. The small rating active filter is used to improve filtering characteristics of the passive filter in SVC and suppress possible resonance between the system impedance and the passive filter. The control signals are derived from the calculation of instantaneous active and reactive powers of the distribution feeder. Simulation results performed by the Electromagnetic Transients Program (EMTP) show that the proposed reactive power compensation configurations can effectively balance currents, correct power factor, and eliminate harmonic currents.