Thermally stimulated current measurements on polymeric cable insulation The diagnostic aspect

摘要

The authors describe results of TSDC (thermally stimulated discharge current) measurements performed on XLPE (cross-linked polyethylene) cable insulation subjected to water tree aging in the laboratory. The measurements show consistent changes of the TSDC spectra with the aging time for both polarized and nonpolarized specimens. The changes observed, which include the reduction of the relaxation temperature with aging time, are more evident after the insulation is subjected to DC polarization stress. It is concluded that the observed changes of the TSDC spectra may prove to be an effective diagnostic tool for assessing the operating conditions of electrical insulation.