Fault Diagnosis of Three-phase Four-wire Active Power Filter Based on Current Feature Extraction

This paper proposes a fault diagnosis algorithm for three-phase four-wire active power filter, which can improve the reliability of active power filter (APF) operation. The algorithm analyzes the current output from the ac side of the APF, integrates the current to obtain the characteristic quantity. Compare the characteristic value before and after the fault, and sets a reasonable threshold. By changing the threshold before and after the fault, the fault can be accurately and quickly located. This method can be applied to single-tube and multitube open-circuit fault diagnosis, has good speed and high reliability, and is suitable for two-level and three-level three-phase four-wire APF systems. The simulation verifies the effectiveness of the proposed algorithm.