Transformer Reliability Survey: Interim Report

In 1983, CIGRE Working Group 12.05 published a report summarizing the results of the analysis of transformers that failed in the period 1968 to 1978. Thirteen countries from 3 different continents took part in this survey. The authors reported of difficulties to compile and analyse the data of the survey due to incomplete or incompatible responses. Ten years later, Working Group 12.14 attempted to upgrade this survey but it was unsuccessful due to similar reasons. Study Committee A2 also started an Advisory Group on Reliability and their findings were presented at the CIGRE 2006 session.