摘要
通过特高压工程的直流输电线路接地故障试验发现,当运行阀组数目较多的一极直流输电线路发生接地故障时,另外一极的电压突变量保护可能会发生误动。为了解决此问题,文中首先指出故障行波共模分量的传输速率要小于差模分量的传输速率,共模分量和差模分量到达保护测点处存在一个时间差。其次,分析出电压突变量保护误动的原因是共模分量和差模分量到达保护测点处的时间差大于电压突变量保护的时间定值。再次,提出将共模分量的极性作为识别故障极的判据并据此改进了电压突变量保护。最后,搭建了特高压直流输电实时数字仿真模型,验证了改进方法分析结果的正确性。
Ground fault tests of ultra-high voltage direct current(UHVDC)transmission line indicate that voltage differential protection of the other pole may be false tripped when the ground fault happens on the line of the pole with a larger number of operating valve groups.In order to solve this problem,it is pointed out that the transmission velocity of common-mode of the fault traveling wave is less than that of differential-mode,and there is a time difference between common-mode and differential-mode to reach the protection measurements.Then,it is analyzed that the cause of the voltage differential protection false tripping is that the time difference between common-mode and differential-mode to reach the protection measurements is longer than the setting time of the protection.In addition,the polarity of common-mode component is used as the criterion to identify the fault pole and the protection of voltage mutation is improved accordingly.Finally,a real-time digital simulation model of UHVDC transmission is established to verify the correctness of the analysis results for the impoved method.
作者
杨建明
张庆武
王杨正
邹强
王永平
YANG Jianming;ZHANG Qingwu;WANG Yangzheng;ZOU Qiang;WANG Yongping(NR Electric Co.,Ltd.,Nanjing 211102,China)
出处
《电力工程技术》
北大核心
2022年第3期102-109,共8页
Electric Power Engineering Technology
基金
国家重点研发计划资助项目(2016YFB0900600)
国家电网有限公司科技项目(52094017000W)。
关键词
电压突变量保护
共模分量
差模分量
传输速率
时间差
时间定值
极性
voltage differential protection
common-mode
differential-mode
transmission velocity
time difference
setting time
polarity
