Harmonic Voltage Effect on Partial Discharge Characteristics of Oil-Paper Insulation Under Non-uniform Electric Field

In the new power system, the harmonic source and the content increase, which puts forward a new test to the oil-impregnated paper insulation performance of the transformer. Therefore, this paper carries out the research on the effect of harmonic voltage on oil-impregnated Paper insulation partial discharge (PD) by means of the partial discharge platform under the action of harmonic voltage, and analyses the influence law of harmonic voltage frequency on partial discharge parameters. The results show that the harmonic voltage changes the partial discharge inception situation for the oil-impregnated paper due to the differences in harmonic polarity at different frequencies from the 50 Hz-industrial voltage. The split-peak phenomenon appears in all of the PD patterns of the oil-impregnated paper under the action of harmonic voltages and it is more obvious in the higher harmonic frequency. The harmonic voltage causes the maximum and average discharge magnitude increases, whereas the number of discharge pulses and discharge repetition rate decreased under the positive and negative discharge.