Relationships between space charge accumulation and electrical or water treeing in improved PE and XLPE by ethylene-acrylic acid copolymer

Polyethylene and cross-linked polyethylene have been improved by various contents of ethylene-acrylic acid copolymer (EAA). The electro-acoustic pulse method is used to observe the space charge distributions in samples. The treeing initiation voltage of samples, DC pre-stressed after short-circuiting, is measured. The water treeing in samples being developed under a number of AC voltages is detected. It has been found by test results that there is a certain relationship between the space charge accumulation and the 50% initiation voltage of short-circuit treeing and the water treeing with the contents of EAA. The space charge accumulation can be regarded as a measure of resistance to electrical and water treeing in samples.