输电线路雷击的电磁暂态特征分析及其识别方法研究

STUDY ON CHARACTERISTICS AND IDENTIFICATION OF TRANSIENTS ON TRANSMISSION LINES CAUSED BY LIGHTNING STROKE

雷击未造成故障引起的行波,在多次折、反射后将最终要衰减为零,因此其表现在时间轴上为正负交替变化,而雷击造成故障与线路故障引起的行波在故障后较短时间内变化趋势总的来说是单调的。根据这一特征,文中用一条直线对故障后的行波进行拟合,并进一步提出了波形一致性系数的概念,依此系数的大小来判断行波是故障行波还是非故障行波。该方法的理论基础较为直观,并通过大量的暂态仿真验证了论文所提出的新方法可靠、有效,而且该方法适用于一切暂态量保护的雷击干扰识别。

The travelling wave, which is caused by lightning stroke without fault generated, will decline to zero after many refractions and reflections. So the waveform of the travelling is alternative around the time axis. However, the travelling wave that is caused by faults and lightning stroke with fault generated, in a whole, will change monotonously in short time. Therefore, a line is used to fit the travelling wave, and the conception of “coefficient of waveform coordination” is presented. According to the value of the coefficient, travelling wave caused by faults can be distinguished from travelling wave caused by others. Lots of simulation show that the presented method is reliable and effective. Further more, this method can be used in any relay based on transient component.