避雷器代替750 kV线路合闸电阻

为满足操作过电压设计限值的要求而使用合闸电阻存在诸多缺点,针对西北电网新建750 kV输电线路过电压水平,对沿线增设1组避雷器取代合闸电阻的想法进行了研究。以即将建成的兰州东-银川东750 kV输电线路工程为背景,利用电磁暂态计算程序(PSCAD/EMTDC)分别计算了沿线装设1组避雷器时,线路三相合空线、单相自动重合闸操作过电压水平。研究结果表明,不采取任何限制措施时,线路三相合空线和单相重合闸操作过电压标么值分别为1.94、2.01,超过线路设计要求1.80,而采用一组避雷器代替线路合闸电阻的方案后,则可改善线路过电压分布情况,并将过电压水平降至设计值1.80以下(三相合空线和单相重合闸操作过电压标么值分别为1.79、1.78)。

Adding One Group of Arresters to Replace Parallel Resistor in 750kV Transmission Line

How to restrict the swithing overvoltage is discussed recently because of the 750 kV transmission line project in Northwest China.Idea of increasing only one group of arrester installed along line replacing with parallel resistance in breakers to suppress switching overvoltage in 750 kV transmission line is realized in this paper.Based on the 750 kV Lanzhoudong-Yinchuandong transmission line project,effects of the arrestor's position on switching overvoltages,including three phases energizing line without load,single phase auto-reclosing are calculated by using the electromagnetic transient program PSCAD/EMTDC.The result shows that without any arresters installed along line,the maximal overvoltage of three phases energizing line with no load(1.94per unit),single phase auto-reclosing(2.01 per unit) are higher than the design limit value(1.80 per unit).Witi the help of one arrester installed along line,the switching overvoltages(the maximal overvoltage of three phases energizing line with no load and single phase auto-reclosing are 1.79 and 1.78 per unit) are acceptable.