Failure Mode Distribution of Transformers in Thailand

This paper evaluates the uptime distribution or failure mode distribution of 22 and 33 kV distribution transformers of the provincial electricity authority of Thailand (PEA). Aging data of 5,343 distribution transformers recorded during 1977-2005 has been used in failure mode distribution evaluation. From uptime data testing, the failure mode of distribution transformers can be represented by the Weibull distribution using curve fitting. From the results, the uptime of distribution transforms installed in later years is constantly higher than the uptime of those installed earlier.