摘要
深入分析了超高压线路差动保护中电流互感器(TA)饱和时的2个重要特征:一是区外故障时TA的工作磁链需要一定的时间累积才能达到饱和点,故障发生初始时刻并不会马上饱和;二是TA在每个周期内由于工频交流分量的负向去磁作用,TA总是一段时间内工作在线性区,一段时间内工作在饱和区。在此基础上,提出了综合利用附加制动区判别法和短数据窗自适应差动保护算法,利用附加制动区来判别区内、区外故障,当区外故障时一旦工作点进入附加制动区,则自适应增大出口判别次数,利用短数据窗差动保护算法本身的线性区范围性能保证保护可靠不误动;当区内故障时,出口判别次数自适应减少,保证差动保护快速动作。动模数据验证结果表明所提出的方法是可行、有效的。
Two important features of current transformer saturation in EHV transmission line differential protection are detailed analyzed. One is that the magnetic flux linkage of current transformer takes certain time to reach the saturation point, that is, the current transformer isn＇t saturated in the beginning of a fault. Another is that the current transformer works in the linear region alternated with saturated region during each cycle due to the negative component of input AC. Based on the above analysis, a short data window based adaptive differential protection algorithm with additional restrained region is presented. The internal fault and external fault can be distinguished by additional restrained region. Once the working point of the differential protection enters the additional restrained region, the operation judgment number is adaptively increased to avoid mal-operation of differential protection. Otherwise the operation judgment number is decreased to ensure a immediate response of protection. Physical dynamic data testing result shows that the proposed method is practicable and effective..
出处
《电力系统自动化》
EI
CSCD
北大核心
2005年第21期67-73,共7页
Automation of Electric Power Systems
关键词
线路差动保护
电流互感器饱和
附加制动区
短数据窗算法
line differential protection
current transformer saturation
additional restrained region
short data window based algorithm
