LAUSR

Residual current device is an important switch apparatus to ensure the safe and reliable operation of the power distribution system. This article proposes a novel fault leakage current detection method to eliminate the protection deadzone that is typically associated with the classical leakage current detection method. The proposed method takes the leakage current variation in addition to the instantaneous root-mean-square (rms) value of the leakage current as the indicator of leakage fault. Three mathematical models of leakage current variation calculation are illustrated in detail and a multilevel leakage fault protection strategy is proposed. Simulation and experimental results are presented to validate the effectiveness of the proposed leakage current detection method, and a comparative evaluation of the classical and the proposed leakage current detection methods is conducted to verify the superiority of the proposed method.