STUDY FOR NEGATIVE SEQUENCE CURRENT DISTRIBUTING AND GROUND FAULT PROTECTION IN MIDDLE VOLTAGE POWER SYSTEMS

How to detect and isolate earth faulty section is an important subject to realize distribution automation in ineffectively grounded systems. Traditional methods for faulty feeder protection based on comparing zero sequence currents are difficult to satisfy the requirement of distribution automation. Negative sequence current.distributing is discussed and new principle for faulty feeder protection based on negative sequence current is presented in this paper. The principle is verified by EMTP simulator and the prototype is developed, which has been tested in dynamic power system model.