Withstand voltage testing in combination with PD measurements of XLPE cables under damped alternating voltage on-site

Abstract

As an after-laying test, withstand voltages and PD measurements of XLPE cables on-site have been finished respectively for many years. Standard test procedures using continuous AC voltages are very cost intensive due to the high capacitive power demand of the cables and the resulting large sizes of the test sets. The contribution paper presents that withstand voltage testing in combination with PD measurements of XLPE cables will be done at the same time under damped alternating voltage on-site. Based on the field experiences including withstand voltage testing and PD detections, a damped alternating current (DAC)voltage generator and a transducer of PD pulse measurement were developed in the laboratory. We established a typical defects model of 10 kV XLPE power cables. For these samples, the applied voltage peak value is from 14-34 kV, simultaneously the PD is measured. The insulation conditions of the samples can be evaluated according to the records of withstand voltage tests and non-destructive dielectric tests. Based on these test models, this paper deems that the damped alternating voltage is an effective test method showing a very high sensitivity of PD detection and recognition of electrical treeing for XLPE cables on-site. using the damped alternating voltage, Both voltage withstand testing and partial discharge testing are made at the same time, we can confirm roundly and accurately the situation of XLPE cables. The future work is that a large of field data based on real XLPE cables needs to accumulate for a long time. In particular, the database of PDs need to set up.