一种基于微分方程法的串补线路精确故障测距算法

ACCURATE FAULT LOCATING ALGORITHM FOR SERIES COMPENSATED TRANSMISSION LINE BASED ON THE DIFFERENTIAL EQUATION METHOD

串联补偿电容的接入使得从线路两端测得的稳态时的电压电流关系不再一一对应,用代数法无法区分故障发生在串补电容的哪一侧,这给以前常用的代数方程定位算法增加了新的困难。文中利用在线路两侧同步采集(用全球定位系统(GPS)进行同步)的电压、电流信号,采用微分方程数学模型并结合串补线路的特点推导了一种新的故障定位算法。该算法分别假定故障点在串补电容的两侧,通过计算得到2个故障定位解,其中一个为真根,另一个为伪根。针对定位过程中出现的真伪根,由暂态过程中电容两侧发生故障时的电压波形不同这一事实,根据线路两侧获取的数据分别计算出的故障点电压应相等这一原理,提出了一种简单、可靠地找出真根去除伪根的方法,可正确判定事故地点。仿真研究表明,该算法具有较高的精度和较强的适应性,能可靠区分真伪根,精确确定事故地点。

Owing to the use of the series capacitor in the transmission line, the stable state V-I characteristics measured at both ends of the transmission line is no longer in one-to-one correspondence, hence the fault locating method based on an algebraic equation cannot be used for transmission lines with series capacitor compensation. A new fault locating principle for transmission lines with capacitor compensation is proposed in this paper. The mathematical model of the method is based on differential equations; the data are collected on both sides of a transmission line and synchronized by GPS. First, we can determine two fault points each located on one side of the compensation capacitor. Then, according to the principle that the voltages of the fault point calculated by the data collected on both sides of the transmission line must be equal, the real fault location can be determined. Both the principle of fault location and the corresponding algorithm are presented in detail, and the simulation results have proved the correctness and feasibility of the method proposed.