Influence of AC Voltage Frequency on Partial Discharge of Oil-Pressboard Insulation and Its Mechanism

The high frequency of harmonic voltage is more likely to cause partial discharge and insulation failure. The partial discharge experimental platform is built to study the partial discharge characteristics of oil-pressboard insulation under different frequency voltages. Based on the analysis of the obtained partial discharge information, it can be found that the spectrum changes with frequency. As the voltage frequency increases, the discharge quantity increases more steeply with the phase. The higher the voltage frequency, the larger the discharge quantity and discharge repetition rate, and the more serious the partial discharge. The accumulation and dissipation of residual charge have an important influence on the development of partial discharge. The higher the voltage frequency is, the slower the residual charge dissipation is, forming a residual electric field to promote partial discharge.