Abstract:
The transient earth voltage (TEV) method is studied in detection performance for switchgear partial discharge, and compared with the pulse current detection method. In addition, the detection capabilities of the two methods are studied for different types of partial discharge, and the similarities and differences of the PRPD (phase resolved partial discharge) spectra of four partial discharge types measured by two methods are analyzed. The variations of the detection results with the applied voltage are analyzed through calculating the statistical characteristics. The results show that, compared with the conventional high-frequency current transformer (HFCT) method, the TEV method has a lower signal-noise ratio in detecting switchgear partial discharge with a slightly inferior detection performance, but it is more suitable for detecting weak tip discharge; in terms of PRPD spectra, the two methods have strong consistency in pulse amplitude characteristics and phase intervals for different types of partial discharge, but there are some differences in pulse concentration and other aspects. With the change of applied voltage, TEV and HFCT methods have the same variation trend of skewness and steepness, and both methods can effectively reflect the discharge characteristics of partial discharge.