Structure and parameters design of output LC filter in D-STATCOM

This paper proposes a novel and practical method to design the parameters of LC filter in distribution STATCOM. The filter parameters are mainly determined by four factors: the resonant frequency, the harmonic distortion rate, inductance fundamental voltage drop, and the reactive power compensation ability. The proposed method in this paper is that selecting larger filter inductance and capacitance on condition that the inductance fundamental voltage drop does not exceed about 20% of the system voltage and that the fundamental current flowing through the capacitance is not more than about 5% of the STATCOM rated output current in order to get a better filtering effect. In addition, this paper points out that connecting a small inductance in parallel with the damping resistance will not only greatly reduce the power loss, but also be good for the filtering effect. Simulation results show that the designed filter structure and parameters have good effects.