Research on Breakdown Characteristics of PP Films for Shunt Capacitors Under Multi-frequency Harmonic Voltages Group

High voltage AC shunt capacitors bear the electrical stress of power frequency superimposed harmonics when running in the field. With the increase of harmonic content in the power grid, the test of capacitor insulation increases. In order to study the breakdown characteristics of polypropylene film for high voltage shunt capacitors under the condition of power frequency superposition harmonics, this paper carried out the breakdown test of polypropylene (PP) film under different voltage frequency combination and different temperature and other influencing factors. The statistical analysis of the breakdown field strength data of the film was carried out by using Weibull distribution. The results show that the breakdown field strength of polypropylene film decreases with the increase of temperature. The breakdown field strength of power frequency superimposed harmonics is lower than that of power frequency, and with the increase of harmonic frequency, the decline of breakdown field strength decreases.