带并联电抗器线路单相永久性故障的识别方法

根据带并联电抗器超高压输电线路传输特性提出了一种基于分布参数模型的过渡电阻计算方法。鉴于永久性故障时,过渡电阻基本稳定在一较小值,而瞬时性故障熄弧以后,过渡电阻计算值迅速上升,据此可以通过过渡电阻的连续计算确定故障性质,同时还可以鉴别熄弧时刻。该方法只需要故障相跳闸后单端并联电抗器电流、单端健全相电流和故障测距结果即可实现判别,实际应用方便。电磁暂态程序仿真和分析表明,该方法在不同故障位置、不同负荷电流和不同过渡电阻情况下均能准确判断,且同时适用于单端和双端带并联电抗器的情况;此外,该方法具有一定的耐故障测距、线路参数和系统频率误差的能力。

An Identification Method of Single-phase Permanent Fault at Transmission Lines with Shunt Reactors

Based on the transmission characteristics of extra high voltage (EHV) transmission lines with shunt reactors, a new algorithm for calculating transition resistance through a distributed parameter model is presented. In view of the case of permanent fault where the transition resistance is basically fixed at a low value, whereas in the case of transient fault, where after the arc is extinguished, the calculated value of transition resistance immediately increases to a large value, we are enabled to distinguish the fault nature, and the extinction time of secondary arc as well. This method can work just by making use of the current of shunt reactors and the non-fault-phase at one terminal, and fault location results, and is easy to use. Electromagnetic transient program simulation results and analyses show that the method is hardly affected by fault location, load current and transition resistance, and can be applied to transmission lines with shunt reactors at one terminal and at both terminals. What's more, the method can withstand the inaccuracy of fault location, transmission line parameters, and system frequency to some degree. This work is supported by National Natural Science Foundation of China (No. 51107112).