Breakdown performance and electrical aging life model of EPR used in coal mining cables

Ethylene Propylene Rubber (EPR) with excellent dielectric properties has been widely used as cable insulation specially to be used where cables need to be moved frequently, such as in coal mine. Usually, theses cables will be bending excessively, coupled with the electric stress and thermal stress, the aging of the insulation tend to accelerate and the strength of insulation could decrease, with the time prolonging, breakdown may be happened. So, it is necessary to make research on the breakdown characteristics of EPR. To understand the breakdown performance, a step-stress test method is used in the accelerated life tests of EPR and WEIBULL distribution is used to analyze the test dates. Finally, based on inverse power life model, the voltage life index of EPR have been obtained. Finally, the electrical aging life model of EPR have be obtained. Research on the breakdown characteristics and the voltage life index of EPR is significance for insulation structure design and residual life assessment.