特高压变电站中带跳线Ⅱ形耐张瓷绝缘子串的均压特性

Voltage-Sharing Characteristics of Ⅱ-Shaped Tension Ceramic Insulator String With Jumpers in UHVAC Substation

由于电压等级高,组装形式多样,受上下层构架塔、相间、导线及跳线等的影响,1 000 kV变电站内盘形瓷绝缘子串的分布电压和高压侧的电场分布很不均匀,需要对其均压特性进行研究。运用三维有限元法,考虑构架塔、导线、跳线、金具及相间等的影响,仿真计算1 000 kV特高压变电站采用的带跳线Ⅱ形耐张绝缘子串的电位和电场分布,研究均压环对其分布电压的影响,比较位于不同位置的绝缘子串的电位和电场分布差异,并通过优化最终给出适用于带跳线Ⅱ形耐张瓷绝缘子串的均压环配置方案。所得研究成果对于提高特高压变电站绝缘子的安全运行可靠性,改善特高压变电站内外的电磁环境具有重要意义,已经成功应用于我国特高压交流试验示范工程,经现场观测,运行效果良好。

In view of high voltage grade and complex structure in UHVAC substation and due to the impacts of upper and lower layer truss towers phase-to-phase spacings, conductors and jumpers, the voltage distribution of dish-shaped ceramic insulator strings located inside UHVAC substation as well as the electric field distribution at the high voltage side of the substation are extremely non-uniform, so it is necessary to research the voltage-sharing characteristics of II-shaped tension ceramic insulator strings inside 1000kV AC substation. Utilizing three-dimensional finite element method and considering the impacts of truss towers, phase-to-phase spacings, conductors and jumpers, the potential and electric field distribution of the If-shaped tension ceramic insulator string with jumpers is simulated and computed; the influence of grading ring on voltage distribution of the insulator string is researched; the differences of potential and electric field distribution Of the II-shaped tension ceramic insulator string located at different positions are compared; and by means of optimizing configuration parameters of grading ring, finally the configuration scheme of grading ring for the II-shaped tension ceramic insulator string with jumpers is given. Results of this research are significant for enhancing the reliability of secure operation of insulator strings of UHVAC substations, improving electromagnetic environment inside and outside UHVAC substation, and have been successfully applied to China＇s UHVAC pilot power transmission project and on-site observation shows that application effect of the proposed configuration scheme of grading rings is satisfied.