Study on the Mitigation Method of Zero-Sequence Harmonic Current in Building Electric System

The tuned harmonic filter in series with the neutral line is an effective method for zero-sequence harmonic mitigation. However, the series tuned filter not only has the de-tuning problem but also inject fundamental impedance into the neutral line. In order to mitigate those negative effects, a continuous auto-tuning zero-sequence harmonic filter based on an active reactor was presented in this paper. Based on the active reactor used harmonic magnetic flux compensation, the simulation system of the series zero-sequence harmonic filter with continuous auto-tuning function was further designed. The simulation results show that this filter can suppress triple-harmonic current, compensate fundamental reactance, and adapt variation of filter parameter.