Polypropylene film is used widely solid insulation and monobenzyltoluene as liquid insulation between the poles of high voltage power capacitor and performance of the power capacitor is therefore improved greatly.However

such faults as oil leakage and moisture are inevitably occurred due to a large number of capacitors in operation.The capacitor

in this case

must not have expansion failure.Therefore

the insulation performance of the insulation between poles under the moisture condition is of great importance for safe operation of power capacitor.In this paper

the insulation strength of natural damped capacitor element is obtained by way of natural moisture of the power capacitor

the withstanding performance of the insulation between poles of high voltage capacitor is judged by such data so to provide reference for the manufacture and operation of powercapacitor.