A Diagnostic Technique to Detect Abnormal Conditions of Contacts Measuring Vibrations in Metal Enclosures of Gas Insulated Switchgear

Better reliability in gas insulated switchgear is the goal of a diagnostic technique for abnormal conditions at large current conducting contacts. The detection of peculiar vibrations from artificially simulated abnormal contacts during current conducting and their measurement in metal enclosures, and distortion of the voltage waveform across the abnormal contacts and their analysis are shown. Fig. 1 shows the contacts used in this experiments. The peculiar vibration in metal enclosure is shown in Fig. 2(a) and its FFT analized results is shown in Fig. 2(b). According to the dependence between vibrations and contact voltage shown in Fig. 3, the vibration peak values at 600 Hz which is even integer times current frequency are increase as the contact voltage increases. As the results, there is a possibility to detect abnormal conditions of contacts by the measurement of metal enclosure vibrations.