Reliability Analysis of Low-Voltage Metal-Oxide Surge Arresters Using Accelerated Failure Time Model

Failure progression of metal oxide-based surge arresters in response to exposure to harmonics is modeled using the accelerated failure time model. Multistress accelerated ageing tests, with and without ac distorted voltage stress, are conducted on arrester samples sourced from different suppliers to obtain baseline and harmonic-factor logarithmic life and reliability functions. A maximum likelihood approach is taken to estimate the accelerated failure time model parameters based on the failure time data. The modeled harmonic-factor reliabilities prove metal oxide varistors life acceleration and show multiplicative failure progression of up to 41 times faster for a total harmonic distortion (THD) content of 8.52% in the applied voltage stress.