基于同步相量测量的N端输电线路故障测距新算法

A New Fault Location Algorithm for N-Terminal Transmission Lines Based on Synchronized Phasor Measurement

鉴于现有多端故障测距方法存在的缺陷,诸如采用未能真实反映实际情况的线路集中参数模型,在T节点附近高阻短路故障时有测距死区,算法过于复杂不易实现,受系统运行方式的影响等,在T节点附近发生高阻短路故障时,无法正确判别故障支路。针对该缺陷,提出一种N端输电线路同步故障测距新算法。首先,由离参考端最远的母线推算离参考端最近的T节点的电压、电流,在该T节点和参考端之间利用双端测距算法求出故障距离;基于该故障距离的分布特点将原N端输电线路的故障测距问题转化为一个T型线路的故障测距问题。然后,提出一种T型输电线路故障测距新算法。该方法无测距死区,克服了传统方法在T节点附近有测距死区的不足,测距精度受过渡电阻、故障类型和负荷电流的影响很小。EMTDC仿真结果表明新算法正确,具有很高的测距精度。

Due to the defects of existing synchronized phasor measurement （SPM） based fault location methods for multi-terminal transmission lines, such as the adopted lumped parameter models of transmission line cannot reflect correctly actual condition, there is dead zone of fault location while the high resistance fault occurred near the teed node, or the algorithm is too complex to implement, the adopted algorithms are affected by operation modes of power system, etc., the faulty branch cannot be correctly judged when high resistance fault occurred near the teed node. For this reason, in this paper a new fault location algorithm for multi-terminal transmission lines using SPM is proposed. Firstly, the voltage and current of the teed node that is the nearest to the reference bus are calculated by the voltage and current data of the bus that is the farthest to the reference bus, and by use of two-terminal fault location algorithm the fault location between the teed node and reference bus is solved; then based on the distribution characteristic of this fault location, the fault location problem of original N-terminal transmission lines is changed into the fault location of a teed transmission line; finally, a new fault location algorithm without dead zone for teed transmission line is given. The given algorithm remedies the defect of traditional fault location methods in which dead zone of fault location exist. The accuracy of the given algorithm is slightly affected by transition resistance, fault types and load current. The results of simulation by EMTDC show that the proposed new algorithm is correct and can locate the faults accurately.