INSULATION DEGRADATION DETECTION METHOD OF SWITCH

PURPOSE:To easily detect, from the outside the insulation status of any sealed electric equipment in its connected state, by detecting the high-degree, high-frequency component in the leakage current flowing in a grounding wire and finding out the content ratio of higher degree, high-frequency wave with a high frequency wave of a certain degree as a reference. CONSTITUTION:An insulation resistor 4a composed of an insulation material and an electrostatic capacitance 4b are interposed between the tank 1 of a vacuum switch and a main circuit conductor 3. Another electric equipment is connected to a grounding wire 6, and the insulation resistor 7a and an electrostatic capacitance 7b of those electric equipment exist between the conductor 3 and the grounding wire 6. A current converter 8 is connected to the grounding wire 6, the power of which is supplied to a high-frequency analyzer 10. The leakage current flowing in the grounding wire 6 is detected by means of the current converter 8, and the high-degree, high-frequency component included in the leakage current is detected. The insulation degradation and humidity status inside the equipment can be detected by monitoring the change of a higher-degree high frequency wave with a high frequency wave of a certain degree as a reference.