Study on Electric Field Distribution and Metal Joints Optimization of Insulated Rods for UHV Live Working

The insulated rods for UHV transmission line live working commonly used with metal joints of the segmented structure. The distribution of electric field near the metal joint is uneven, and the phenomenon of discharge is easy to occur. In this paper, the electric field distribution simulation of insulated rod for 1000kV UHV transmission line live working under the typical operating conditions is performed. Aiming at the serious electric field distortion, the influence of the number of metal joints is discussed. An improved scheme of adding grading ring at the head metal joint is proposed. Simulation results show that the maximum electric field intensity of the insulated rod metal joint surface is 3816 kV/m during live work, which is 54% larger than that of transmission line surface in normal conditions(without insulated rod), and the increase of the number of metal joints has small effect. The maximum electric field intensity appeared on the grading ring after adding it to the outside of the head etal joint by 100 mm in cover depth and 60 mm in diameter, reducing to 2138 kV/m. The effect of electric field distribution optimization is obvious.