Thermally stimulated discharge current observation of cross-linked polyethylene

As cross-linked polyethylene (XLPE) is the most typical and suitable insulating material for electric power cables, various studies on its physical properties have been reported where a thermally stimulated discharge current (TSDC) observation method was found to be very effective for understanding chemical contamination and structural change, such as additive effects and X-ray radiation damage. The authors observed such TSDC of charged XLPE films or an actual power cable from room temperature (about 20 degrees C) to 100 degrees C to understand the AC stressing effect. Corona charging and typical DC field charging in hot air, SF/sub 6/, or oil were tested to make charged samples. In gas, the degradation effects caused by AC stressing were identified by the TSDC as a heterocurrent peak shift from 60 to 80 degrees C. However, in the oil test, the annealing effect is found to be dominant for the TSDC and a pure field stressing effect is not recognized. >