A new accurate fault locating algorithm for series compensatedlines

This paper presents a new, accurate and robust fault locating algorithm for series compensated lines. The algorithm is developed as a one-end fundamental frequency based technique and offsets both the series compensation effect and the reactance effect resulting from the remote end in-feed. The method uses phase coordinates (abc) instead of symmetrical components (012). The basic algorithm is presented for a line compensated by one three-phase bank of series capacitors. The presented fault locating method has been extensively tested using the EMTP model of a 400 kV 300 km transmission line. The enclosed results demonstrate very high accuracy and robustness of the algorithm     

基于PMU的多端传输线路故障定位新方法

提出一种基于PMU的多端传输线路故障定位新方法;该算法基于线路分布参数线路模型和同步附加正序分量,通过故障区域判断指标,准确找到故障支路,然后将非故障支路化简合并,应用双端测距算法进行高精度的故障测距.本算法的测距不受故障类型、故障阻抗、系统阻抗及负荷等的影响,PSCAD仿真结果验证了所提算法的正确性和高精度性.     

A WAMS/PMU-based fault location technique

A WAMS (wide-area measurement/monitoring system)/PMU (phasor measurement unit)-based fault location technique is proposed in this paper. The technique uses synchronized fault voltages of two nodes of the faulted line and their neighboring nodes for fault location. Based on these fault node voltages measured by PMUs, line currents between these nodes can be calculated. Then, node injection currents at two terminals of the faulted line are formed from the line currents. Based on the calculated fault node injection currents, fault node can be deduced or fault location in transmission lines can be calculated accurately. Fault location formulas are derived in full details. Case studies on IEEE-14-bus system and a testing network with 500 kV transmission lines including ATP/EMTP simulations are given to validate the proposed technique. Various fault types and fault resistances are also considered.     

分布式发电系统故障定位新算法

分布式电源(Distributed Generation,DG)接入配电网后,配电网由单电源辐射状网络变成了分布电源供电的复杂网络,保护的运行环境发生了深刻变化.根据分布式发电系统结构和特点,提出一种基于分布决策的故障定位新算法,进行网络划分形成智能电子装置(IED)的关联区域,利用关联区域边界节点信息完成故障初步定位,再根据故障关联区域的节点连接关系,利用各区段两端节点信息精确定位故障.算法采用静态区域划分,划分结果可动态修整,降低了实时性要求且对IED信息缺失及DG投切造成的电网结构变化具有一定的适应性;故障一次和二次定位原理清晰,信息和计算量小.通过对算法的算例分析,验证了算法的正确性.     

A new PMU-based fault detection/location technique for transmission lines with consideration of arcing fault discrimination-part II: performance evaluation

The theory and algorithms of the proposed technique have been presented in Part I of this two-paper set. In Part II of this two-paper set, the proposed technique is evaluated by considerable simulation cases simulated by the Matlab/Power system Blockset simulator. For the proposed fault detector, the trip time achieved can be up to 3.25 ms and the average value of trip times is about 8 ms for both permanent and arcing faults on transmission lines. For the proposed fault locator, the accuracy can be up to 99.99% and the error does not exceed 0.45%. Moreover, the proposed arcing fault discriminator can discriminate between arcing and permanent faults within four cycles after fault inception. It has proven to be an effective tool to block reclosing on the permanent faults in the computer simulations. The simulation results also demonstrate that the presented extended discrete Fourier transform algorithm eliminates effectively the error caused by exponentially decaying dc offset on fundamental and harmonic phasor computations. Finally, a test case using the real-life measured data proves the feasibility of the proposed technique.     

A new fault location algorithm for radial transmission lines withloads

Conventional fault location schemes do not take loads and their variable impedance behavior into account. This leads to unacceptable errors in the case of radial transmission lines with loads, commonly found at the 120 kV and lower levels. A novel method for such lines is proposed. The fault distance is obtained by solving an implicit equation. Single-phase-to-ground, phase-to-phase, and three-phase-to-ground faults are treated. The effect of the scheme is illustrated by simulated faults     

A new PMU-based fault detection/location technique for transmission lines with consideration of arcing fault discrimination-part I: theory and algorithms

A new fault detection/location technique with consideration of arcing fault discrimination based on phasor measurement units for extremely high voltage/ultra-high voltage transmission lines is presented in this two-paper set. Part I of this two-paper set is mainly aimed at theory and algorithm derivation. The proposed fault detection technique for both arcing and permanent faults is achieved by a combination of a fault detection index |M| and a fault location index |D|, which are obtained by processing synchronized fundamental phasors. One is to detect the occurrence of a fault and the other is to distinguish between in-zone and out-of-zone faults. Furthermore, for discriminating between arcing and permanent faults, the proposed technique estimates the amplitude of arc voltage by least error squares method through the measured synchronized harmonic phasors caused by the nonlinear arc behavior. Then, the discrimination will be achieved by comparing the estimated amplitude of arc voltage to a given threshold value. In addition, in order to eliminate the error caused by exponentially decaying dc offset on the computations of fundamental and harmonic phasors, an extended discrete Fourier transform algorithm is also presented.     

A performance oriented impedance based fault location algorithm for series compensated transmission lines

This paper proposes a performance oriented fault location algorithm for series compensated transmission lines. The algorithm estimates the fault location based on the calculated fault voltage and current using two end measurements and line parameters. Fault location computations are carried out considering faults existed before or after the compensator location on the line. The calculated MOV impedance is the key factor in determining whether or not the fault is located in front of the compensator. A 380 kV transmission line with a series capacitor and an MOV has been tested for various fault types, fault locations and fault resistances. The results show that the algorithm accurately estimates the fault location for all cases.     

高压线路双端测距新算法

提出了一种新颖的超高压输电线路故障双端测距精确算法.该算法采用相-模变换技术和分布参数线路模型,考虑了双端数据的不同步问题,运用拟牛顿法迭代求解非线性方程组.仿真计算其表明具有很高的精度.     

高压线路双端测距新算法

提出了一种新颖的超高压输电线路故障双端测距精确算法。该算法采用相-模变换技术和分布参数线路模型,考虑了双端数据的不同步问题,运用拟牛顿法迭代求解非线性方程组。仿真计算其表明具有很高的精度。     

一种新的输电线路双端测距算法

提出了一种新颖的超高压输电线路故障双端测距精确算法。该算法采用相—模变换技术和分布参数线路模型,考虑了双端数据的不同步问题,运用拟牛顿法迭代求解非线性方程组,仿真计算表明具有很高的精度。     

A new fault location algorithm using direct circuit analysis for distribution systems

The unbalanced nature of distribution systems due to single-phase laterals and loads gives difficulty in the fault location. This paper proposes a new fault location algorithm developed by the direct three-phase circuit analysis for unbalanced distribution systems, which has not been investigated due to high complexity. The proposed algorithm overcomes the limit of the conventional algorithm, which requires the balanced system. It is applicable to any power system, but especially useful for the unbalanced distribution systems. Its effectiveness has been proved through many EMTP simulations.     

基于抗差估计理论的输电线路故障定位新型算法

针对采样中出现的粗差,提出了一种基于抗差估计理论的故障定位算法.通过等价权原理,将抗差估计理论和最小二乘法有机的结合起来,有效地避免了粗差的影响.算法采用微分方程作为数学模型,并利用相模变换解耦;然后,在模域采用输电线路双端信号列写故障点方程;最后,用抗差最小二乘法求解.经过RTDS实验表明,该算法结果稳定,具有很好的准确性和抗干扰能力.     

高压输电线路单端故障测距新方法

提出了一种新的单端故障测距的方法,根据故障发生后的故障附加网络,利用单端故障电压电流计算沿线故障电压对距离的导数,然后再求其范数在线路上的分布,根据其分布特点确定故障点的位置,实现测距.仿真证明该新方法具有较高的准确度和稳定性.     

基于Stehfest算法的配网单相接地故障双端测距方法

提出了一种基于Stehfest算法的双端测距方法。该方法采用配网单相接地故障后半周期内的零序电压、电流暂态信息,由Prony算法得到其时域表达式,利用零序网络以及线路分布参数的象函数模型,在不考虑线路零序参数的频率特性和考虑其频率特性两种情况下,分别列写出线路的象函数测距方程。通过Stehfest算法对测距方程进行数值反演计算,并用搜索法求取区间内测距方程的最小值,得到方程的数值计算矩阵,进而以该矩阵行元素平方和最小为目标,确定故障距离。大量的EMTP-ATP仿真实验验证了该方法的正确性。     

高压输电线路单端故障测距新方法

提出了一种新的单端故障测距的方法,根据故障发生后的故障附加网络,利用单端故障电压电流计算沿线故障电压对距离的导数,然后再求其范数在线路上的分布,根据其分布特点确定故障点的位置,实现测距。仿真证明该新方法具有较高的准确度和稳定性。     

基于抗差估计理论的输电线路故障定位新型算法

针对采样中出现的粗差,提出了一种基于抗差估计理论的故障定位算法。通过等价权原理,将抗差估计理论和最小二乘法有机的结合起来,有效地避免了粗差的影响。算法采用微分方程作为数学模型,并利用相模变换解耦;然后,在模域采用输电线路双端信号列写故障点方程;最后,用抗差最小二乘法求解。经过RTDS实验表明,该算法结果稳定,具有很好的准确性和抗干扰能力。     

基于改进RL模型的串联补偿线路单相接地故障测距新算法

基于RL模型算法的测距式继电器是我国最早开发成功并获得广泛应用的微机线路保护继电器,但其直接应用在串联电容补偿线路中具有一定的局限性。基于此,针对常见的单相接地故障类型,给出了一种基于改进RL模型的串联补偿线路故障测距算法。该算法考虑了故障过程中MOV动作及串联电容对线路实际阻抗值的影响。与传统的串联补偿线路故障定位方法相比,该算法无需判断串联补偿装置是否在故障回路中,也无需知道串联补偿装置的相关参数和其具体工作状态,就能简单准确地实现串联补偿线路的故障测距。EMTDC/PSCAD和Matlab仿真计算结果表明,所提出的算法能够获得比传统算法更加准确的测距结果。     

基于改进RL模型的串联补偿线路单相接地 故障测距新算法

基于RL模型算法的测距式继电器是我国最早开发成功并获得广泛应用的微机线路保护继电器,但其直接应用在串联电容补偿线路中具有一定的局限性。基于此,针对常见的单相接地故障类型,给出了一种基于改进RL模型的串联补偿线路故障测距算法。该算法考虑了故障过程中MOV动作及串联电容对线路实际阻抗值的影响。与传统的串联补偿线路故障定位方法相比,该算法无需判断串联补偿装置是否在故障回路中,也无需知道串联补偿装置的相关参数和其具体工作状态,就能简单准确地实现串联补偿线路的故障测距。EMTDC/PSCAD和Matlab仿真计算结果表明,所提出的算法能够获得比传统算法更加准确的测距结果。     

基于分布参数模型的混合线路故障测距新算法

通过研究基于分布参数模型的传统架空线路双端电气量测距方法,针对混合输电线路电气参数不一致的问题,提出了一种基于连接点电压比较分段故障定位的双端测距新方法.该算法基于混合输电线路分布参数模型,通过双端电流、电压值及不同线路电气参数推算各连接点处电压并比较其幅值大小,确定故障发生区段,利用故障区段两端连接点电压、电流按传统单一输电线路双端电气量测距原理计算故障距离.理论分析和ATP/MATLAB仿真表明,该方法能够准确确定电缆-架空线混合输电线路故障位置,并适用于更为复杂的多段混合输电线路.