Development of Partial Discharge Diagnostic Method for Switchgears with Noise Reduction and Classification Technology

Partial discharge (PD) detection is one of the effective method for switchgear's insulation assessment to prevent unexpected power outages. Among many PD sensors, transient earth voltage (TEV) sensor has some advantages for on-site PD testing because it can detect PD signals by just attach to enclosure wall of switchgears without outages, and small size, easy handling, etc… This paper presents an insulation diagnostic technology with TEV sensor in combination with noise reduction and PD identification methods. Discrete wavelet transform and k-means method are applied to noise reduction and classification for PD diagnostic system respectively and result indicates effectiveness of proposed method.