Research on Feeder Zero Sequence Overcurrent Protection Adaptive to Network Topology Changes

The wiring in A+ and A power supply areas is complex and the operation modes are diverse. The neutral point is mostly grounded by low resistance. Based on distribution automation, the principle of feeder zero-sequence overcurrent protection based on adaptive network topology change is proposed. The influence of distribution network topology change on feeder grounding fault zero-sequence current is analyzed. And the adaptability evaluation method of feeder zero-sequence overcurrent protection is proposed. For the distribution network using local feeder automation, the feeder zero-sequence overcurrent protection is circumvented by prohibiting certain operation modes; for the distribution network with feeder automation with communication function, the network topology is judged by using the information collected by distribution automation, and the zero-sequence overcurrent protection setting is modified online after the network topology changes to avoid the feeder zero-sequence overcurrent protection from malfunctioning. The distribution network model is established using PSCAD, and a large number of fault simulations are performed. The results show that when the the distribution network topology changes, the proposed adaptive zero-sequence overcurrent protection will not malfunction.