Property Changes of Transformer Oil during Limiting States of Transformer

Power transformer service availability is influenced by a condition of insulating and cooling medium - by transformer oil properties. The transformer is subjected to many untypical situations arising casually or due to changed operation conditions. Between the casual phenomena belongs e.g. an unbalanced loading, which causes phases overload etc. These situations reflect on the properties of cooling medium. Parameters such as an excessive formation of gasses in transformer oil, an increase of water presence in the oil or changes of temperature distribution along the winding of transformer can be changed during the operation. Monitoring of these changes is performed in our experimental department, which was developed directly for this purpose. Tested transformer is equipped with sensors for mentioned parameters monitoring. Information obtained from laboratory testing of the experimental transformer will be useful for assessment of processes proceeding in common operation of these devices.