41 / 2021-05-25 19:42:31

Operating Status Analysis and Improvement Measures of Porcelain Insulator with External Zinc Ring for UHVDC Transmission Line

This paper statistically analyses the operating conditions of two extra-high voltage DC lines with zinc rings. It is considered that the horseshoe-shaped zinc ring structure defect is the main reason for its drop. In addition, the horseshoe-shaped zinc ring and the iron cap gap are not tightly combined during operation, and may not play the role of sacrificial anode. The electrolytic corrosion of the iron cap is still developing. It is proposed that the external zinc ring should be fully enclosed, and the inward force should be applied to keep the zinc ring tightly combined with the iron cap gap in operation. The structure should be simple and convenient for single-person installation at high altitude. Three modified zinc ring improvement schemes were designed, and electrolytic corrosion tests were carried out in the laboratory. The results show that the improved zinc ring can play the role of sacrificial anode under the condition of full enveloping, and the connecting members have better anti-corrosion effect and are easy to install.