Electroluminescence test to evaluate dielectric property at the interface between semiconductive shield and insulation

The electroluminescence test is a relatively new technique to investigate the dielectric performance of semiconductive shields and crosslinked polyethylene insulation interfaces. It is based on the electric field (voltage) at which light emission occurs as a result of charge injection and carriers recombination for a given sample geometry. A standardized sample geometry with a semicon needle-plane electrode was utilized under amplified voltage in a dry condition to monitor the electroluminescence inception voltages of crosslinked polyethylene (XLPE) and tree retardant crosslinked polyethylene insulation (TR XLPE). It resulted that EL inception voltage of TR XLPE is higher than that of XLPE. In water tree growth test, TR XLPE demonstrated to retard water tree growth under the wet aging condition.