Assessing the Significance of Electro-Thermal Stress on Varistor Arresters Using Kruskal-Wallis H-Test

In this study, the effect of electro-thermal stresses on the microstructure of low-voltage zinc oxide varistors is experimentally investigated. Accelerated ageing tests, based on continuous ac voltage stress at several thermal points, are conducted prior to linear intercept on scanning electro microscopy-based micrographs. The Kruskal-Wallis H-test is used to assess the extent of microstructural changes in the tested varistor arresters. Results obtained show significant change in the microstructure of the varistor arresters as a result of electro-thermal treatment.