According to Ronaldo Bertoldi, Engineering Manager at WEG Transformers Africa, testing transformer oil is a key function end-users should build into their maintenance programmes, as it speaks volumes about the condition of the transformer itself. Access to regular oil test results makes it easier to identify potential problems arising in transformers, and to take corrective action to avoid expensive damage or unplanned downtime.

Testing transformer oil is essential“The dissolved gas analysis (DGA) test is one of the most important for a customer to conduct, as it provides the first available indication of malfunction within a transformer unit. The DGA indicates the internal condition of the unit, and identifies degradation taking place. It is therefore essential for effective monitoring and trend analysis,” Bertoldi says.

“It is also important to measure the amount of cellulose in the oil, as this is an indication of the extent to which the paper around the winding is degrading and turning to sludge. Judging by how much cellulose is in the oil, a prediction on the life expectancy of the transformer can be provided. Even the simple oil colour test has a useful function in showing oil quality, indicating that further investigation may be necessary to keep the transformer well maintained.”

Bertoldi adds that as one of the largest manufacturers of transformers in South Africa, WEG Transformers Africa has a state-of-the-art oil laboratory at its production facility in Heidelberg, and offers an extensive range of services to transformer owners. The laboratory is able to perform a range of important routine tests. These include the ‘kV’ test which passes current through the oil to test its insulative properties and a water test to measure the parts per million of water in the oil. As a conductor of electricity, high levels of water become damaging and dangerous to the transformer’s continued operation.

“All test results are kept in our extensive database, which allows a history of the trend analysis to be available to each of our customers. We use these figures daily in developing trends for a particular customer or even a particular transformer unit,” Bertoldi concludes.

Image credit:  Copyright: federicofoto / 123RF Stock Photo


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