Harmonic resonance phenomena in STATCOM and relationship to parameters selection of passive components

As an important element of the STATCOM, the passive component plays an indispensable role in the process of active and reactive energy storing and exchanging. However the coupling of the AC inductance and DC capacitance may lead to harmonic resonance. In order to investigate its influence on STATCOM performance, a simplified per unit model of STATCOM is developed in this paper. The relationship of the resonant frequency and the magnitudes of resonant AC current and DC voltage to the parameters of passive elements are derived. The good agreements between the analysis and the experimental results show that the model proposed here can be used in the selection of the passive parameters in the design of an actual STATCOM.