A review of electrical and thermal multistress aging models

A review of the methods and models used in lifetime studies of solid insulators under single- and multiple-stress conditions is presented. The statistical methods used with this type of data are briefly described. These statistical methods include the two-parameter Weibull distribution and log-normal distribution, which are the two distributions most frequently used in aging studies. The most attention is given to lifetime models under multiple stresses which have recently generated considerable interest. In particular, several models under combined electrical and thermal stresses are presented and their applicability is analyzed and discussed. These include the multistress models proposed by L. Simoni (1981) and T.S. Ramu (1985), both using the inverse power law for electrical aging, the exponential model by B. Fallou et al. (1979), and the probabilistic model by G.C. Montanari and M. Cacciari (1989). The trend in the development of these models is discussed