Research on leakage protection method based on double terminal residual current sudden changes

In order to overcome the shortcomings of the existing single terminal leakage protection methods, the leakage protection technology based on multi-terminal information should be studied. Based on the analysis of the characteristics of singlephase leakage faults in low-voltage distribution lines, a leakage protection method based on double terminal residual current sudden changes is proposed in this paper, which uses the amplitudes of the double-terminal residual current sudden changes of the protected section as the protection criteria. The protection will act when the double terminal criteria both meet the requirements of their respective setting thresholds. The realization processes and performances of the method are given in the paper. The double terminal residual current information of the protected section is comprehensively utilized by this method, which can effectively eliminate the influence of unbalanced leakage current of line during normal operation and other factors, reduce protection maloperation and improve the utilization rate of protection. It doesn't need multi-level protection delay coordination and has fast action speed; and it has low setting thresholds and high sensitivity. The effectiveness of the method is verified by MATLAB simulation.