Statistical considerations on impulse breakdown characteristics of cross-linked polyethylene insulated cables

This paper describes a statistical analysis of impulse breakdown stress of cross-linked polyethylene insulated cable (XLPE cable) with the concept of weak-point distribution in insulation. The dependence of breakdown stress on cable size is presented. Comparing them with failure data, it is found that the breakdown stress depends not on maximum stress at the conductor but on average stress throughout the insulation Weibull distribution location parameter is estimated. The relation between breakdown stress and cable length is presented considering the lowest value. Breakdown characteristics caused by repeated impulse application are also investigated.