A Relay Scheme for Distribution Networks Considering the Control Mode of Inverter-Based Distributed Generator
In the distribution system including distributed generators, it is difficult to meet the requirements of selectivity and sensitivity for traditional current protection. Currently, inverter-based distributed generators (IBDG) are widely used in distribution systems. The transient process of IBDG is rapid, and its transient characteristics are influenced by the control strategy. The controlled current source equivalent model of IBDG with positive-sequence P-Q control is put forward. After analyzing the fault characteristics, the protection scheme using negative sequence current is proposed, which can be used in the distribution systems including IBDG under positive-sequence P-Q control. The simulation results on a 10kV distribution system have verified the correctness of faults characteristics and the effectiveness of protection scheme.