Charge carrier transportation in the composite of Nano-MgO and cross-linking polyethylene

Space charge behavior of the composite of polyethylene and nano-MgO was investigated with pulsed electroacoustic method (PEA). It is found that space charge was well suppressed as the content of nano-MgO is less than 2.0% wt. Also it could be seen that bi-polar injection occurs in the composite as electrical stress increases to 60 kV/mm. Comparing to the amount of space charge in the short-circuited pure cross-linking polyethylene, it is very low in the composite. It is more interesting that semiconductive electrode has a great effect on space charge in both cross-linking polyethylene and the composite. In order to know space charge injection threshold, dc conduction was measured at various electrical stresses. And it is found that nano-MgO increases the threshold.