Influence of load characteristics on the applications of passive and active harmonic filters

Passive filter and active filter are two alternative strategies to suppress harmonics in the electrical distribution system. The passive filter is economic and efficient but it may cause resonance problems. The active filter has become a mature technology and will considerably be generalized in the near future. In this paper, a laboratory which consists of 110 kVA six-pulse rectifier loads, one 50 kVA active filter, and six-step 54 kVAr passive filters has been constructed. Characteristics of harmonic voltage source and harmonic current source are investigated by experiment and simulation. The passive filter and active filter are applied to different harmonic sources by turns and the harmonics after compensation are measured. It is observed from the experimental measurements that application of passive filter or active filter to harmonic voltage source will amplify the harmonic currents at the load side and a larger capacity of filter is needed