Measurement of solid dielectric surface temperature increment arising from partial discharge activity

Measurement of the temperature increment of the dielectric surface caused by partial discharge activity was carried out by means of non-invasive measuring system which takes an amount of infrared radiation energy emitted by the surface. The experiment was run in a point-dielectric-plane electrode arrangement with AC voltage up to 22 kV and frequency range from 200 to 1200 Hz. Samples of Epoxy resin with an alumina filler (EP), Polytetrafluoroethylene (PTFE), and Polyethylene (PE) were investigated. It was found that temperature increment may be so high that thermal degradation of the dielectric is possible.