Research on resistive residual current detection technology based on fast fourier transform

The resistive leakage current caused by the insulation damage or aging of the elevator line is the main monitoring target of the electrical fire detector. However, due to the influence of the capacitance component of the elevator power supply cable and the motor to the ground, the detector is prone to false alarms. In this paper, the fast Fourier transform is used to analyze the phase of the residual current and the neutral line voltage, and the detection and protection methods of the slowly varying resistance residual current and the abrupt resistance residual current are proposed. The experimental results show that the method can effectively detect the elevator resistance residual current and improve the accuracy of the protector action.