Online Monitoring Device for Partial Discharge in High-Voltage Switchgear Based on Capacitance Coupling Method

There are many problems in traditional manual inspection, such as poor real-time performance, complex operation and large environmental impact on monitoring results when using ultrasonic and ultra high frequency (UHF) inspection methods. In order to realize online monitoring of partial discharge (PD) in high-voltage switchgears, a live display capacitance sensor equipped with high-voltage switchgear is proposed to acquire discharge pulse and monitor the discharge information of switchgear in real time. With the technology of FPGA, the sampling frequency of 50MHz is used to collect one million data points in 10 milliseconds and a half cycle. Hanning window function data processing technology and fast Fourier transform (FFT) technology are used to obtain the high frequency discharge spectrum of the internal ports and insulators of high-voltage switchgear cabinet, thus realizing the online monitoring of PD, and greatly reducing the cost of the monitoring circuit. It is convenient for popularization and application, and meets the online monitoring requirements of PD through practical tests.