特高压变压器中性点经小电抗接地及其过电压保护研究  

Research on Neutral Point Grounded by Small Reactance and Its Overvoltage Protection of UHV Transformer

作　　者：赵宏成 张旭航 曹炜 陈宗正 高生凯 ZHAO Hongcheng;ZHANG Xuhang;CAO Wei;CHEN Zongzheng;GAO Shengkai(School of Electrical Engineering,Shanghai Electric Power University,Shanghai 200090,China;State Grid Shanghai Electric Power Company Economic and Technical Research Institute,Shanghai 200120,China;State Grid Hebei Electric Power Company Handan New District Power Supply Branch,Handan 056107,China)

机构地区：[1]上海电力大学电气工程学院,上海200090 [2]国网上海市电力公司经济技术研究院,上海200120 [3]国网河北省电力公司邯郸市新区供电分公司,河北邯郸056107

出　　处：《电瓷避雷器》2022年第3期109-115,共7页Insulators and Surge Arresters

基　　金：国家自然科学基金青年自然基金项目(编号:51807114)。

摘　　要：特高压变压器中性点经小电抗接地在降低线路单相短路电流的同时,提高了中性点的过电压水平,为中性点配置合适的过电压保护十分重要。本研究运用EMTP对华东某特高压变电站进行等值建模,对变压器中性点串接多个阻值小电抗后限制短路电流能力进行量化分析,从而确定中性点小电抗的最佳取值。根据工程实际,变压器中性点串接小电抗后,在中性点并联氧化锌避雷器和放电间隙可以提供一定的过电压保护。由于避雷器动作后残压过高,会使放电间隙击穿放电,考虑用可控避雷器替代氧化锌避雷器以实现最佳的绝缘配合。The neutral point of the UHV transformer is grounded with a small reactance to reduce the single-phase short-circuit current of the line and increase the overvoltage level of the neutral point. It is very important to configure appropriate overvoltage protection for the neutral point. The author uses EMTP to perform equivalent modeling on a UHV substation in East China, and quantitatively analyzes the ability to limit the short-circuit current after connecting a series of multiple resistance small reactances to the neutral point of the transformer to determine the optimal value of the neutral point small reactance. According to the actual project, after the transformer neutral point is connected in series with a small reactance, parallel connection of zinc oxide surge arresters and discharge gaps at the neutral point can provide certain overvoltage protection. Since the residual voltage is too high after the arrester operates, the discharge gap will break down and discharge. Using a controllable arrester to replace the zinc oxide arrester can achieve the best insulation coordination.

关 键 词：小电抗 中性点 变压器 过电压保护 放电间隙 避雷器 

分 类 号：TM41[电气工程—电器] TM862