Study of Measurement and Detection Algorithm of LVDC Residual Current

With the rapid development of dc system, the residual current in dc system has become an urgent problem to be solved. However, the type B residual current devices (RCD) for ac systems could not be directly used in dc systems. The ac residual current caused by distributed capacitance and the rectifier seriously interferes with the accurate detection of the dc residual current. A detection simulation model of dc residual current based on magnetic modulation was established. The authors also proposed detection algorithms based on Kalman filter and moving average filter separately. The experimental results showed that the proposed model and detection algorithms were effective. They could detect the residual current in the dc system under ac interferences.