Fault diagnosis for shunt hybrid active power filter with open-circuit fault based on voltage distortion

Switches in shunt hybrid active power filter are prone to damage. However, too much time is needed in traditional fault diagnosis methods with relatively high misdiagnosis rate. A new fault diagnosis method based on voltage distortion is proposed. Open-circuit fault is detected rapidly by catching the distortion of the capacitor voltage and comparing it with the normal value. At the same time, the faulty switch can be located. By this method, the fault location can be diagnosed accurately and rapidly in a half period. Simulation results for open-circuit fault occurred in different locations verified the effectiveness, validity and rapidity of the proposed method.