Analysis on IIDG's negative-sequence current upon asymmetric fault

As a large number of distributed generations (DG) are connected to the distribution network, the fault current of the distribution network has been changed, and the reliable operation of relay protection in the distribution network has been influenced. In the background whether the negative-sequence current protection can be used in the distribution network containing inverter interfaced DG (IIDG), this paper studies the mainstream method of controlling the fault characteristics of inverter based on negative-sequence component, analyzes and deduces a negative-sequence control structure, demonstrates the inhibitory effect of negative sequence control algorithm on the fault current, and has important reference value in proposing the protection principle for IIDG-containing distribution network. Finally, RTDS test simulates the asymmetric short-circuit fault conditions of the photovoltaic inverter, to verify the conclusions of this paper.