Analysis and interpretation of dissolved gases in transformer oil: A case study

Condition monitoring plays a vital role in any asset management plan. Dissolved gas analysis is a routine test carried out on power transformers to monitor their condition. Four power transformers selected from a repository of power transformers due to their dissolved gas levels exceeding the normal levels are analyzed using the Key Gas Method, the Roger's Ratio Method and the Duval Triangle Method to diagnose any faults. The results show that for some transformers all three diagnosis methods agree on the type of fault, whilst for others it is not so straightforward in diagnoses. In this study, the condition of each power transformer is predicted using the above methods.