Detection of wide-band E-M signals emitted from partial discharge occurring in GIS using wavelet transform

Recently, diagnostic techniques have been investigated to detect a partial discharge (PD) associated with a dielectric material defect in a high-volta ge electrical apparatus. Gas Insulated Switchgear (GIS) is an important equ ipment in a substation, it's highly desirable to measure a partial discharg e (PD) occurring in GIS which is a symptom of an insulation breakdown. As i t is important to develop a noncontact method far detecting the insulation fault, this paper proposes a new method to detect the wide-band electromagn etic (E-M) wave emitted from PD using the Wavelet transform. The Wavelet tr ansform provides a direct quantitative measure of spectral content, "Dynami c spectrum," in the time-frequency domain This paper experimentally shows t he "Dynamic spectrum" of the wide-band E-M wave emitted from PD in the time -frequency domain. This method is shown to be useful for detecting the symp tom of the insulation breakdown occurring in GIS.