AbstractResonant harmonic filters (RHF) commonly used for reducing waveform distortion in distribution systems have a number of disadvantages. Their effectiveness degrades with an increase in the distortion of the distribution voltage. The current harmonics other than those to which the filter is tuned can be amplified. Filter performance is very sensitive, usually, to reconfigurations in the distribution system. Active harmonic filters are alternative for RHF. They have high complexity, however, and their dissemination in distribution systems seems to be rather slow. This paper investigates another alternative for RHF, namely a harmonic blocking compensator (HBC) built of a shunt capacitor and a series resonant link tuned to the fundamental frequency. This paper compares properties of RHF and HBC, provides fundamentals for the design of HBC and illustrates their properties with results obtained with a laboratory prototype.