A Novel Three Tuned Filter for Power System

With the characteristics of traditional single tuned filter and double tuned filter analyzed,a novel three-tuned filter for power system is proposed.The filter is equivalent to three single tuned filters.It is constructed with three capacitors and three conductors.Its impedance and frequency curve are also analyzed.Algorithm for determining the filter's parameters is presented.The inductances and the capacitances can be calculated from the given data such as rated voltage,tuned frequencies,parallel resonant frequency and reactive compensation capacity.A three-tuned filter for a 110kV power grid is designed,simulated and tested.The results show that the filter can filter three different given frequency harmonics,the frequency error is no more than 2Hz, and the filter has better performance than that of three single-tuned filters in filtering harmonics,lower power loss, lower space,lower price,only one reactor subjected to power line-voltage and one switchgear needed.The novel three-tuned filter will be implemented on the power system in China.