A New Method of the Touch/Leakage Protection without Dead-Zone Considering the Phase Characteristics

Abstract

After investigating the residual current protection and its major deficiencies, it is found out that the touch/Leakage current could be separated from the total residual current by the current separation technology , which is based on the phase relationship between normal residual current and touch/leakage current. A novel leakage current protection principle without protection dead-zone is proposed .The proposed method, which is put into practice on DSP , proves to be accurate and feasible in digital simulations. Compared to the existing techniques based on the residual current amplitude or its variation,the proposed method can eliminate protection dead-zone effectively and improve the reliability of protection devices drastically.