Influence of Phase of Multi-frequency Harmonics on Breakdown Characteristics of Polypropylene Film for High Voltage Shunt Capacitors

Harmonics in the power grid distort the voltage at both ends of the high voltage shunt capacitor and affect the insulation of the polypropylene film inside the capacitor. In order to study the effect of the phase of harmonics on the insulation characteristics of polypropylene films, an experimental platform for breakdown of polypropylene films for high voltage shunt capacitors was established. The phase of the harmonics voltage was changed and record the breakdown field strength of the polypropylene film under different conditions. The effect of the phase of the harmonics voltage on the breakdown voltage of the polypropylene film was analyzed using the two-parameter Weibull distribution. The results show that the breakdown field strength of polypropylene film decreases with the increase of temperature, and the harmonics leads to the decrease of the breakdown field strength of polypropylene film. Moreover, the phase of harmonic voltages affect the breakdown characteristics of polypropylene films by changing the peak and rise rates of voltage.