A Statistical Method to Evaluate the Working Life of MOV

Abstract

Metal Oxide Varistor (MOV) is the key component to suppress overvoltage and divert surge current in the electrical systems. The evaluation of the MOV working life is an expectation of MOV manufacturers and users. This paper provides a statistical method to evaluate the working life of MOV with the Weibull distribution. Firstly, the theories of the Weibull distribution and median rank regression (MRR) method are introduced. Then the procedure to evaluate the three parameters of the Weibull cumulative distribution function (CDF) is provided through a life-test experiment with the random-selected MOV samples. Finally, the evaluation procedure is concluded as four steps.