Distribution and effect of space charge on dielectric properties in modified XLPE by chlorinated polyethylene

The cross-linked polyethylene (XLPE) is modified by a small amount of chlorinated polyethylene (CPE). The space charge distribution in the samples is measured with electroacoustic pulse method. The relation of space charge densities with content of CPE is explored and its optimum content for decreasing space charges is determined. The effect of CPE on the initiation voltage of short circuit treeing after pre-stress of dc voltage is studied. It is shown by test result that when the content of CPE is 10%, the 50% treeing initiation voltage, depending on the polarities of dc voltage, are increased by 42.3% and 35.5% respectively. Finally, the other dielectric properties of samples are measured and the electrical stress distributions distorted by space charges in samples are calculated. The relative mechanism is discussed.