Time-frequency analysis of E-M signals emitted from a partial discharge occurring in GIS using wavelet transform

Diagnostic techniques have been investigated to detect a partial discharge (PD) associated with a dielectric material defect in a high-voltage electrical apparatus such as gas insulated switchgear (GIS). We propose a new method to detect the wide-band electromagnetic (E-M) waves emitted from PD using the wavelet transform The wavelet transform can provide a "dynamic spectrum" in the time-frequency domain. This paper experimentally shows the "dynamic spectrum" of the wide-band EM waves emitted from PD. This method is shown to be useful for detecting PD occurring in GIS.