Analysing of insulating system oil-paper of power transformers by frequency dielectric spectroscopy

Paper presents experimental diagnostics of insulating system oil-paper for power transformers, mainly by progressive frequency method – dielectric spectroscopy. The introduction of the article is described the base analysing for measurement insulating elements (oil and paper) of power transformers. The next part of article is described application of dielectric frequency domain spectroscopy (FDS) method for high-voltage power transformers. Diagnostic methods are used for measurement of insulating state of high-voltage devices with insulating parts as oil-paper. It was present that the values of these measuring results are highly impacted by the temperature of operating during the experimental diagnostics. Conductivity and moisture between dielectric transformer paper and insulating oil in an dielectric system are highly dependent from internal and ambient temperature. In the final section the article are presented experimental values of the diagnostic analysis for an operating oil traction transformer at different internal temperatures and conditions (with oil filling and without).