高压输电线路单端测距新原理探讨

突破了传统的利用工频分量的单端测距概念和利用初始行波与故障点反射行波到达测量点的时间差进行单端测距的概念,提出了一种新的单端故障测距原理。该原理利用单端电压电流计算沿线电压对距离导数的范数在线路上的分布进行故障点的定位。通过对故障线路的分析发现,利用单端量对全线路的电压分布进行计算,其结果在故障点后方,是“虚假”的,但这个“虚假”的电压分布对距离的导数与真实的电压分布对距离导数有相似的变化规律。同时还发现,故障线路上电压对距离导数的范数（有效值）在故障点呈现最小值,那么,利用单端量计算的电压分布导数的范数最小值点就是故障点,EMTP对该原理的初步仿真证明,该算法具有比较高的准确度,但还有一些问题需要进一步的研究。

A NOVEL PRINCIPLE OF SINGLE-ENDED LINE FAULT LOCATION TECHNIQUE FOR EHV TRANSMISSION SYSTEMS

A new fault location algorithm using derived information of one terminal is proposed in the paper, based on distributed parameter line model. As to a healthy line, using traveling wave theorem, one can get the voltage profile along the line using single-ended data. However, it is not the ease to a faulted line, the computed voltage at the point behind the fault point using the single-ended data is not true, we call the computed voltage profile as "Fictitious Voltage Profile". By our analyzing the relations between the "Real Voltage profile" and "Fictitious Profile", it is concluded that, the minimum norm value of derivative of real voltage profile and fictitious profile to distance is at the same point, that is, at fault point. Therefore, the fault location algorithm is proposed as following: (i) compute the fictitious voltage profile along the line using the single-ended data; (ii) compute the norm value of derivative of the fictitious voltage at each point and search the minimum point, which is the fault point. The EMTP simulation tests show that the algorithm has the quality of more accurate; however, some problems should be solved later.