High Temperature Breakdown Characteristics in Polyethylene Film with Fixed Electrodes

Electrical breakdown was investigated in films of low-density polyethylene by the application of both pulsed waveform and ramped voltages. Stainless-steel ball electrodes and the film to be measured were embedded in a thermoset resin. The breakdown strength FB increased with temperature T, ∂FB/∂T>0, between about 80°C and 100°C by application of impulse voltages. This temperature range corresponds to a region of heat absorption in DSC curves. We believe that the input energy rate from impulse voltage melts the crystalline lamellae and causes an increase of electrical breakdown strength.