An Attempt to Investigate Transformer Failure by Dissolved Gas Analysis

Reliable and continued performance of power transformer is the key to profitable generation, transmission & distribution. Power transformer failures lead to power supply interruptions in developing nations like India. DGA technique plays an important role in nullifying these unforeseen interruptions. One of the best methods of detecting certain problems which can lead to failure of the transformer is dissolved gas analysis (DGA). failure rate of transformers is very high in India - 25% per annum which is not favorable compared to international failure rate of 1-2%. To prevent failures, effective analysis and diagnosis needs to be investigated. Transformer failures presented in this paper are catastrophic and of high interest. Case studies are presented here for the transformers which have higher fault gas concentrations.

An attempt has been made in this paper to assess in-service transformers, new transformers after factory tests and internal condition of service on load tap changers by dissolved gas analysis.