Accuracy of the ageing parameters estimation during double-stress tests of metallized capacitors [insulation life testing]

The accuracy of the results of life tests performed on insulating materials or systems may be influenced by the testing procedure, particularly significantly under accelerated multistress conditions. The accuracy of the life-model parameters estimated from these tests depends on the number of stress levels, values of applied stresses, the number of samples, tools and methods for estimation and on kind of data (censored or not). In this paper, using the Weibull distribution function and scale or shape parameters estimated by maximum likelihood and least squares methods, the accuracy of the exponential double-stress life model for metallized capacitors is discussed