Review on condition monitoring and life extension of transformer

The leading cause of transformer failure is ‘insulation failure’, which includes oil contamination. Cause of transformer failure due to inadequate operation and maintenance has to bear the blame for not discovering incipient troubles when there was ample time to correct it. Regular sampling and testing of insulation oil taken from transformer is a valuable technique in a preventive maintenance program. If a proactive approach is adopted based on the condition of the transformer oil, the life of the transformer can be extended. This paper presents a simplified overview on the importance, major protection accessories, various tests and their significance related to transformer oil, to facilitate the operator to review the options and make a decision on how to treat the oil. Finally a brief description and method is explained to measure transformer oil Interfacial Tension (IFT) by ring method and it's relation to Neutralization Number (NN) along with technical details of an instrument to measure IFT.