A Study on the Extraction Method of Partial Discharge Features in Gas Insulated Switchgear Based on Ultra-High Frequency Signal Envelope

Abstract

Because the UHF detection method has the advantages of wide detection range and high sensitivity, it is of great significance for partial discharge detection and defect type identification in gas insulated electrical equipment. Therefore, this paper proposes a new type of partial discharge UHF signal pattern recognition algorithm, which can effectively identify the type of partial discharge defects. The low frequency signal modulated by high frequency signal is demodulated by Hilbert transform. This paper presents a method to extract the time domain characteristics of UHF signals emitted by gas insulated switchgears (GIS) partial discharge (PD). By using the Hilbert transform, the envelope of partial discharge signal can be obtained, and then the key points related to features in time domain can be obtained. The artificial insulation fault test platform is developed. Experimental data of three typical partial discharge signals are obtained, and the algorithm is analyzed and verified. The result shows that the method can recognize different types of PD well. So it is practical and effective.