Voltage and frequency dependence of tree growth in polyethylene

Accelerated life tests of polymer insulation is used to get rapid life distribution data. Low-density polyethylene (DED 2005) used as the specimen was heated for 15 min at 130°C. A needle electrode was then inserted into the specimen. The needle tip was ground to an angle of 30° and a radius of curvature of 5 μ. The arrangement of electrodes in the specimens is shown in Fig. 1. The test frequencies were 50, 300, 1000, 3000, and 10,000 Hz.