Fault Analysis of Power Transformers from North Eastern Region by Dissolved Gas Analysis

The Dissolved Gas Analysis (DGA) is an effective technique for transformer fault diagnosis in oilimmersed transformers. The presence of certain key gases is monitored and quantified. Numbers of methods are used to analyse and interpret the gases formed inside the transformer. Key gas, rogers ratio, IEC ratio and Duval Triangle are the most frequently used methods. The DGA data of around 255 power transformers from the utilities of the North Eastern Region are analysed to interpret the transformer condition. The types of fault and their probability with transformer service life, power and voltage ratings are discussed.