基于零序有功的谐振接地电网选线新方法

By making a thorough analysis of active line selection principle and the course of factors affecting the accuracy of line selection, a novel zero-sequence active line selection method which can eliminate the influence of unbalanced current is proposed in this paper. In the method, the amplitude and phase of actual fault zero sequence current are calculated so as to eliminate the influence of unbalanced current in the grid and enlarge the differences of active component between the fault feeder and the sound feeder, thereby, improving the accuracy of line selection. The corresponding simulation is carried out by using PSCAD. Simulation results show that the selective protection principle based on the proposed method has a high accuracy and a great ability of anti-disturbance. It also applies to any distribution system with different grounding patterns and not be affected by the value of grounding resistance or the degree of fault phase.