중성선 영상 고조파 전류 저감을 위한 하이브리드 전력 필터

According to the development of power switching device technology, the power conversion system is used from the small electric power units to the large industrial instruments. These instruments are operated as harmonic sources in the grid and the harmonics cause zero sequence harmonics in the neutral line. To reduce zero sequence harmonics, the zigzag transformer is used conventionally. But the zigzag transformer can reduce only 60∼70% of harmonics. In this paper, hybrid power filter for zero sequence harmonics reduction and the harmonic detection method are proposed.