Estimating aging parameter of XLPE and its nanocomposites under AC voltage using step-stress test

Our previous studies showed that the aging parameter, i.e. the n-value, of XLPE was quite different from that of XLPE nanocomposites. In order to investigate the effects of space charge on aging parameter under DC voltage, the n-values of XLPE and its nanocomposites were measured under AC voltage in this report, because few space charge exits in the sample under AC voltage. Step-stress tests were carried out under AC voltage to measure the n-value. The results showed that the aging parameters of XLPE and its nanocomposites under AC voltage were close, i.e. 7.3 and 6.6, respectively. This suggests that space charge accumulation plays an important role in DC aging.