Discharge current method-a test procedure for plastic-insulated medium-voltage cables

The diagnostic method for medium voltage cables based on the method of discharge current is an integral measurement technique, which means that the dielectric properties of an insulating material can only be measured in general, singular vacancies cannot be detected. The nonlinear correlation between charging voltage and discharge current is a criterion for the state of ageing of the insulating material and gives information about its condition. The authors briefly discuss the determination of ageing of plastic insulated cables and the course of measures as follows: period of charge; period of self-discharge; and period of discharge