Endurance characteristics of XLPE compounds under DC voltage

The voltage endurance lines under DC electrical stress obtained from accelerated life tests performed on specimens of a reference XLPE (extra-clean) and two XLPE-based compounds are reported in this paper. The two compounds differ from the base material by the introduction of additives having the purpose of modifying the conductivity and trapping states, thus resulting in dynamic space-charge trapping. Both constant-voltage life tests and tests with periodic inversion of DC voltage are considered. It is shown that the voltage endurance lines may significantly change for voltage-reversal tests, to an extent which depends on the type of material tested.