Design and Application of a Wireless Intelligent Detection System for Leakage Current of MOA

Metal oxide arrester (MOA) online monitoring systems are increasingly used in smart substations, but there are also some problems in project operation, such as difficulty in measuring reference voltage, inaccurate monitoring data, poor integration. In order to solve the above problems, this paper developed a high-precision wireless intelligent detection system for reference voltage and leakage current of MOA. It directly measures the bus voltage on the secondary side of the CVT, and transmit wireless signals for a long time as a phase reference for the whole station to use. The leakage current measurement is started at the voltage zero-crossing, and the dielectric loss angle is calculated through Hanning windowed interpolation fast Fourier transform (FFT) algorithm. The voltage and current measurement circuit contains automatic gain adjustment functions and self-calibration functions and the changes caused by the sensor and filter can be corrected by itself. Through comparative experiments in the laboratory, we have proved the effectiveness of the wireless intelligent detection system.