Control of three-phase converter for ground fault capacitive current compensation in ungrounded distribution networks

In this paper a control strategy of three-phase semiconductor converter of electrical energy for ground fault capacitive current compensation in ungrounded distribution networks is described. A mathematical average model of the inverter is obtained. Used decomposition method of the three phase voltage and current into instantaneous positive, negative and zero sequences based on Hilbert transform are described. A control algorithm of converter with using of three phase system decomposition into symmetrical components is designed. The controller of each sequence uses dq0 frame rotating and PI (proportional integral) controllers. The simulation results of inverter with capacitive current compensation in the short circuit mode are presented.