Improvements for pilot protection in distribution grid with full converter wind turbines

Wind power gradually occupies important proportion in modern power grid. The influence of wind turbine generator (WTG) for protective relays has been studied in recent years, but a very few papers are presented to study relative influence to primary protection. This paper proposes a detailed analysis for the operating characteristic of transmission line primary protection in power network which are connected to wind farms. When fault occurs on tie lines, fault current is fast restricted by the regulating effect of full power converter and the operation of chopper protection. Consequently, indispensable improvements are illustrated to overcome the sensitivity deficiency of primary protection. Simulation tests based on IEEE 34-bus system with high wind penetration demonstrate the validity of presented methods.