Trap and carrier transport of pristine and aged silicone rubber by surface potential measurements

Silicone rubber is widely used in power equipment such as cable joint. In order to get better performance of insulator, it is significant to evaluate the insulation condition of aged silicone rubber insulators. Thus in this paper, surface potential decay measurement has been applied to investigate the performance of pristine and aged silicone rubber. Pristine and aged silicone rubber samples are charged by positive and negative corona discharging. Then the surface potentials are measured by a non-contact probe. It is found that surface potential in aged rubber decays faster, which is resulted from more shallow traps generated during ageing process, for electrons are easier to migrate or even trap out of the shallow traps. Additionally, carrier mobility shows an increase in aged rubber for both positive and negative charges, which may be resulted from the increase in shallow traps in the material. As regards to conductivity, it turns out that conductivity in aged rubber is higher than that in pristine one, which indicates charges in aged rubber migrate faster and further proves the conclusion mentioned that shallow traps increase in internal material.