Discharges Current, Emitted Light and Radiated Field in Power Transformer Insulating Oils

The present paper deals with current, emitted light and radiated magnetic field simultaneous measurements in power transformers liquid dielectrics. They have been analyzed in both temporal and frequency domains. The investigation focuses on the nanosecond scale for electrical signals and Megahertz scale for spectral signals. The results enlightened that many similarities exist between the three parameters. They are characterized by a powerful frequency activity between 25 and 120 MHz. Moreover, it has been found, thanks to a simple ANN, that when the magnetic field is known, it is possible to predict the light emission variation with a good accuracy, and vice versa.