Installing the rubber sheath on transmission line to improve the performance of external insulation of line insulator

A novel method, installing the rubber sheath on power transmission line near the insulator string to improve the performance of external insulation of line insulator, was proposed in this paper. The physical model of line insulator and transmission line installed the rubber sheath was shown, and the calculation formulas of the insulator voltage, the sheath voltage and the sheath capacitance value were given. Based on the physical model and the calculation formulas, the conclusions, changing the sheath capacitance value could improve the insulator performance, and altering the thickness, dielectric constant of sheath and the length of conducting layer on the surface of sheath could adjust the sheath capacitance value, were drawn. Taking the 220 kV composite insulator as an example, the results of computer simulation and experimental research indicate that theoretical basis is correct and installing the rubber sheath can improve line insulator performance.