串补线路的数学形态学行波测距法研究

因存在串联电容及其并联保护元件MOV,带串联电容补偿装置的输电线路的高度非线性特性对故障测距和继电保护产生了较大影响,使常规的故障测距和距离保护算法均已不再适用。为此,讨论了串联电容补偿对输电线路行波法测距的影响,并提出了一种基于数学形态学梯度技术的串补线路行波法故障测距新算法,该算法不受MOV非线性特性的影响。相对于小波变换等积分运算来说,形态学对突变信号检测能力强,对噪声不敏感,算法简单,耗时较小,易于硬件实现。ATP仿真结果表明,该算法具有很好的准确性和鲁棒性。

New Algorithm of Traveling Wave Fault Location for Series Compensated Line Using Mathematical Morphology

It is very difficult for series compensated power transmission line to locate the fault occurred on it and to set the protective relaying.Because of the high non-linear characteristic of MOV parallel installed with capacitor,there is a great impact on protection and fault location,and the conventional algorithm for fault location is not suitable for series compensated lines.This paper put emphasis on the influence of series capacitor compensation on the traveling wave fault location of HV transmission lines,and a lot of simulations are carried out to analyze the influence of MOV on traveling wave fault location.This paper also presents a new traveling wave fault location algorithm for series compensated lines based on mathematic morphology gradient technology which can efficiently extract the fault characteristics of transient traveling wave and reflects the time of refraction and echo of fault traveling wave.Since only the data at two milliseconds after MOV operation are used,MOV's nonlinear characteristic does not need be considered in this algorithm.Furthermore compared with the wavelet transform modulus maxima theory,detection capability of signal using mathematical morphology gradient technology is stronger,and is not sensitive to noise.The algorithm is simple,time-saving and easy to apply for hardware.In this paper,transmission line is expressed using distributed parameters model.The MOVs are simulated by exponential model;the presented algorithm has been extensively tested using the ATP model of a 500kV 300km transmission line.The simulation results show that this algorithm has not only high accuracy but also robustness.