基于改进双端测距原理的带变压器线缆混合线路故障定位方法

Fault Location Method of Hybrid Line with Transformer Cable Based on Improved Two Terminal Distance Measurement Principle

针对架空线-电缆混合输电线路中在连接点处装设有变压器的线路故障测距问题,本文分析了行波经变压器传播时的波形特点,并提出了一种基于改进双端测距原理的故障定位方法。首先,通过HHT消除行波经变压器衰减导致各次行波波头幅值减小而无法准确提取的缺陷,获取行波到达线路两端的时刻并求取两端时间差值Δt;其次,通过将时间差值代入由整定值构造的时间轴,由Δt在时间轴上的位置得到故障点所在区间;最后,由计算公式求得故障距离。仿真结果表明本文中方法正确可行,适用于带变压器线缆混合线路类型,且具有较高的测距精度和可靠性。

In the Overhead line-cable hybrid transmission line, directing against line type of installing transformer at the connection point and solving the fault location problem of this line type, In this paper, the waveform characteristics of traveling wave passing through transformer are analyzed, and a fault location method for hybrid cable with transformer based on improved two terminal ranging principle is proposed. Firstly, the Hilbert-yellow transform is used to eliminate the defect which can not be extracted accurately by the attenuation of the traveling wave through the transformer, which reduces the amplitude of the wave head of each line. The time difference between the two ends of the line reached by the Hilbert-yellow transform is obtained at both ends of the line, and the difference between the two ends is Δt. Secondly, By bringing the time difference into the time axis constructed by the set value, the position of the fault point is obtained by the position of Δt on the time axis. Lastly, the fault distance is calculated by the formula. The simulation results show that the proposed method is correct and feasible. The method proposed in this paper is suitable for the type of hybrid line with transformer and cable, and It has higher ranging accuracy and reliability.