Open-switch fault diagnosis and system reconfiguration of doubly fed wind power converter used in a microgrid

Microgrid is becoming more and more popular in the west and north of China, where there is abundant wind energy. For the microgrid, the faults in the wind generation system usually result in the power accidents. The open switch fault of wind power converter is one of the faults, and many diagnosing methods have been developed. To avoid the disadvantages of current open-switch fault diagnosing methods for a doubly fed wind power converter, an anti-false-alarm method, which can detect one or two open switch faults is proposed in the paper, which is based on the investigation of the characteristics of current signals. Simulations were carried out to test the method presented in the paper, and results indicate the diagnosing method cannot only detect one open switch fault, also two open switch faults at the same time. In addition, the false alarm caused by the open switch fault at the rotor side can be avoided. Finally, a system reconfiguration topology was designed to keep the doubly fed induction generator (DFIG) continue running after the open switch faults. Simulation results show that the method can detect the locations and styles of open switch faults precisely, and the system reconfiguration strategy can restart the DFIG rapidly.