Study on the Effect of Pressure on Breakdown and Electrode Loss Behavior of Metallized Polypropylene Films

Owing to the property of self-healing, metalized film capacitors can be reliably used under high electric field. However, self-healing is at the expense of capacitance loss. High interlayer pressure is often promoted to reduce the capacitance loss. Research has shown that an increase in interlayer pressure can lead to a decrease in the breakdown field and self-healing area of the metallized film, and the impact of the two on capacitor performance is opposite. Therefore, further analysis is necessary. a metallized film breakdown platform was established. The breakdown probability distribution of the metallized film under different pressures were studied. Based on the experimental results of breakdown field and self-healing area, the loss area of capacitor electrode under different electrical field and pressure was calculated. The breakdown characteristics of metallized polypropylene film under the pressure of 20kPa - 1MPa were studied. The breakdown field of the metallized film decreases significantly with the increase of pressure. When the pressure exceeds 200kPa, the influence of pressure on the breakdown electrical field shows a saturation trend. There are two opposite effects of pressure on the capacitance loss of metallized film capacitors. Through theoretical calculation, it is found that the electrode loss increases with the increase of pressure under low electric field. But the electrode loss is very small at this time. The great electrode loss under high electric field can be inhibited by increasing the pressure. Therefore, increasing the interlayer pressure to a certain extent is beneficial to the reliability of the capacitor.