Frequency Diagnostics of Insulating System of Power Transformers

Abstract

Paper presents experimental diagnostics of insulating system oil-paper for power transformers by progressive frequency method. The first part of paper deals with the base information about diagnostics of power transformers. The second part of paper deals use of method of frequency domain spectroscopy (FDS) for power transformers. This method is used in analysis insulating condition of power transformer with system of oil-paper. It was found, that the results of these tests are highly impacted by the operating temperature during the experimental measurement. Moisture and conductivity between insulating transformer paper and oil in an insulating system are highly dependent from temperature. In the other part, the paper presents experimental results of the diagnostic measurement for a real traction transformer at different operating temperatures and states (with oil and without). Finally, the paper presents comparing measurement among several the same power autotransformers. In experimental measurements are shown a correlation between the measured values and the operational aspects of the individual transformers.