Parallel operation of passive power filter and hybrid power filter for harmonic suppression

Harmonic pollution has been serious in recent years. Passive filters have been used to suppress harmonic current conventionally. However, passive power filters have the problem of resonance. To solve the resonance problem, active power filters and hybrid power filters were developed. After considering the power capacity and cost, the hybrid power filter is the better choice for the future. Many passive power filters have already been installed in the industry power systems. However, the elements of these passive power filters are often destroyed due to the resonance or the harmonic current injection of a neighbouring harmonic source. To improve the performance of passive power filters, a small capacity of hybrid power filter is proposed to connect in parallel with the existing passive power filters. In this paper, the combined power filter system, which contains the parallel operation of existing passive power filters and hybrid power filters, is analysed and simulated. The simulation results show that the filter performance and resonance problem of existing passive power filters can be improved by applying the hybrid power filter.