Evaluation of Polyolefin High-Voltage Insulating Compounds; Dendrite (Tree) Formation Under Highly Divergent Fields

A continuing investigation into the dielectric breakdown of polyolefin resin is reported. When sharp needle-point electrodes are embedded into solid resin, the highly divergent field allows relatively slow development of discharge channels, which can be observed as they grow to produce ultimate failure. The merits of two different electrode systems are discussed: (1) a single molded-in needle with a remotely located external ground, and (2) both high-voltage and ground electrodes, molded-in.