Residual Lifetime Estimation by the Mixture Weibull-Power-Law Model

Abstract

A new statistical estimation method of the lifetime of the insulation which had been used for a long period by using the probabilistic mixture model of the Weibull-power-law is shown in this paper. The cross-linked polyethylene insulated cables which are used under the ground are considered to be deteriorate at various rates in accordance with their stress circumstances. Such a phenomenon leads us to propose the mixture model. This method can be applied to the residual lifetime estimation of the removed cables which had been used under the specified service voltage stress for a long period. For example, the parameters and the residual lifetime estimates are obtained for 22 kV and 33 kV cables which had been used for decades by classifying the whole samples into four groups. The estimated deterioration rates totally differ from those obtained by the conventional accelerated life tests.