Initiation and growth of electrical trees in LDPE generated by impulse voltage

The initiation and growth of electrical trees generated by impulse voltages were studied in a molded low-density polyethylene (LDPE) specimen with a metal foil electrode. The Weibull plots of the number of impulse voltage shots to the tree initiation and the puncture of the specimen were analyzed. The difference between the plots of positive and negative impulses demonstrates the difference between the initiation and growth of positive and negative trees. Taking account of the estimation of the electric field strength in the vicinity of the electrode, the tree initiation process was examined. Through the examination of the Weibull plots of the number of impulse voltage shots up to the puncture of the specimen the deterioration of LDPE caused by the impulse tree was analyzed.