Space Charge Characteristics of SiR Insulation of 220 kV AC Cable Joint Accessories

As a potential insulating material, the physical and chemical properties and dielectric properties of silicone rubber (SiR) are being widely studied. Up to now, most scholars are studying the charge transport mechanism and space charge accumulation phenomenon of SiR under DC electric field, and lack of research on this characteristic under AC electric field. Therefore, this paper takes the SiR material in the 220kV AC cable joint as the test object, and studies the space charge accumulation phenomenon of the sample under the 50 Hz frequency, <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$1-20 \text{kV} / \text{mm}$</tex> field intensity sine wave polarization electric field through PEA method, and reveals the mechanism of the space charge storage of the SiR sample under the AC electric field affected by the field intensity change. The results show that under the AC electric field, the charge polarity and charge amount accumulated in the SiR sample change with the phase change of the sinusoidal voltage, and with the increase of the field strength, the space charge accumulation of the SiR sample gradually increases, and it is mainly based on the same polarity charge injection.