High-capacity hybrid power filter for harmonic suppression and reactive compensation in the power substation

A practicable high-capacity hybrid power filter system, with low cost and small bulk, is proposed, which is able to compensate harmonic currents and reactive power simultaneously in the high-voltage power substation. The proposed system consists of a group of high-capacity passive filters and an active filter with a series resonance injecting circuit interface which is assumed by one branch of the passive filters. Reactive power compensation and most of harmonic current suppression is assumed by the passive filters. The active filter in the proposed system is mainly used to improve the characteristics of the total filter system but not dedicate to compensate reactive power, and it doesn´t support the line voltage directly, so the DC-link voltage and the power rating requirement of the power stage is low. At the same power rating, it has the ability to provide larger compensation capacity in higher voltage power system than the usual ones. The operating principle, analysis and control of the proposed system are deeply discussed in the paper. The engineering application is also stated in detail. In the end, the experimental results are given to verify that the proposed system has good characteristic of reactive power compensation and harmonic filter