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。     

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。     

A new fault location method for distribution networks using sparse measurements

In response to the growing demand to improve reliability and quality of power supply, distributed monitoring devices are gradually being implemented in distribution networks. On the other hand, utilities are demanding more accurate and reliable fault location systems to reduce the economic impact of power outages. This paper presents a novel method that takes full advantage of all available measurements to provide an accurate fault location. The developed method first uses an iterative state estimation based algorithm to find the nearest node to the fault location. It then examines all lines connected to the selected node and locates the fault. The performance of the proposed method is studied by simulation tests on a real 13.8 kV, 134-node distribution system under different fault scenarios. The results verify the accuracy of the algorithm and its robustness even under uncertain measured data. The method robustly handles measurement errors, and is applicable to any distribution network with laterals, load taps and heterogeneous lines.     

Improved fault location algorithm for radial distribution systems with discrete and continuous wavelet analysis

This paper presents a novel wavelet based approach for fault location using voltage transient waveforms in power distribution systems. The proposed method includes two main stages. Firstly, the approximate location of the fault or fault section is determined using a new algorithm with discrete wavelet transform. The difference between arriving times of transient components in different measurement units is used for this purpose. The accurate location of the fault is determined in the second stage. Depending on the determined fault section, the difference between arriving times of transient components in different measurement units or the frequency content of the voltage transients are used. The time difference and frequency content are calculated using discrete and continuous wavelet transform (DWT and CWT) respectively. The proposed technique is implemented on an unbalanced 34 bus distribution system with two distributed generation units which is simulated in ATP–EMTP. The comparison of the results of the proposed method with previous works verifies its better accuracy and more robustness to fault conditions including fault inception angle and fault resistance.     

10kV直配线路单相接地故障测距的新算法

提出了10kV直配线路的单相接地故障测距的新算法,该算法利用故障时接地倒相开关将另一非故障相进行一次瞬时接地所构成的零序故障回路,将单相接地故障转化为两点异相接地故障,从而实现对单相接地故障的准确测距。该方法成功解决了中性点不接地系统单相接地故障时,由于没有故障电流回路而造成测距困难的问题。理论分析和仿真结果证明本文提出的算法原理完善,概念清楚,具有很高的测距精度,而且不受过渡电阻和负荷电流的影响,具有很好的实用性。     

10kV直配线路单相接地故障测距的新算法

提出了10 kV直配线路的单相接地故障测距的新算法,该算法利用故障时接地倒相开关将另一非故障相进行一次瞬时接地所构成的零序故障回路,将单相接地故障转化为两点异相接地故障,从而实现对单相接地故障的准确测距.该方法成功解决了中性点不接地系统单相接地故障时,由于没有故障电流回路而造成测距困难的问题.理论分析和仿真结果证明本文提出的算法原理完善,概念清楚,具有很高的测距精度,而且不受过渡电阻和负荷电流的影响,具有很好的实用性.     

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。     

A new PMU-based fault location algorithm for series compensatedlines

This paper presents a new fault location algorithm based on phasor measurement units (PMUs) for series compensated lines. Traditionally, the voltage drop of a series device is computed by the device model in the fault locator of series compensated lines, but when using this approach errors are induced by the inaccuracy of the series device model or the uncertainty operation mode of the series device. The proposed algorithm does not utilize the series device model and knowledge of the operation mode of the series device to compute the voltage drop during the fault period. Instead, the proposed algorithm uses two-step algorithm, prelocation step and correction step, to calculate the voltage drop and fault location. The proposed technique can be easily applied to any series FACTS compensated line. EMTP generated data using a 30-km 34-kV transmission line has been used to test the accuracy of the proposed algorithm. The tested cases include various fault types, fault locations, fault resistances, fault inception angles, etc. The study also considers the effect of various operation modes of the compensated device during the fault period. Simulation results indicate that the proposed algorithm can achieve up to 99.95% accuracy for most tested cases     

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.     

含分布式电源配电网多重故障定位的研究

为适应含有分布式电源(DR)的配电网发展需求,提出了一种较简洁的基于矩阵算法的含分布式电源配电网多重故障定位(可含有馈线末端故障)的方法。该算法首先对无关信息排除精简,然后根据网络描述矩阵形成故障判别矩阵,最后给出障定位的统一判据。还对故障信息畸变的情况给出了解决对策。算例测试结果验证了该方法的正确性和可行性。     

配电网故障定位容错算法

非健全故障信息下故障区段的快速准确定位对于提高配电网供电可靠性具有重要作用。分析首端电压、电流量和短路回路等值电抗的关系,提出基于径向基函数(RBF)神经网络的短路回路等值电抗估计方法,仿真分析表明短路回路等值电抗估计结果受故障距离、过渡电阻的影响较小。然后,以馈线终端设备(FTU)故障信息和短路回路等值电抗为故障特征,应用改进的BP神经网络构建故障区段定位模型。对大量测试样本的分析表明,改进的BP神经网络建立的故障区段定位模型比极限学习机网络算法的定位精度高、泛化能力好,短路回路等值电抗能够辅助修正FTU故障信息的畸变,提高BP神经网络故障定位的容错性。     

配电网故障定位容错算法

为了兼顾配电网故障定位的速度和容错性,提出了一种先故障定位后信息畸变判断的新方法.根据馈线终端单元(FTU)反馈的故障信息,采用基于子节点数搜索的基本定位算法,得到故障区段向量;对故障区段向量进行逆运算得到期望故障信息;将期望故障信息和FTU反馈的故障信息进行比较,根据信息畸变数最小和故障区段最少原则确定最佳故障区段.仿真结果表明,该算法有效减少了基本定位的搜索次数.而且,对于信息缺失畸变情况下的多故障定位,也具有很好的实时性和容错性.     

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     

An improved fault analysis algorithm for unbalanced multi-phasepower distribution systems

The results of an improved method for fault calculations in unbalanced multi-phase power distribution systems containing nonutility generators and large induction motor loads are presented in this paper. The method utilizes a combined time- and frequency-domain analysis approach to produce results that are superior to those obtained in “classical” fault analysis without the large increase in computer time with complete time-domain solutions. Sources and loads can be represented by either classical frequency-domain models or detailed differential equation models. The potentially unbalanced power distribution system is represented by an admittance matrix formed using a linear graph-based application of AC circuit theory. The time-domain differential equation source and load models are interfaced with the frequency-domain distribution system model using time series analyses to estimate equivalent voltage and current phasors from discrete data sets     

分布式发电条件下配电网故障定位的矩阵算法

分布式发电(DG)接入配电网后,配电网变成了多电源复杂网络,传统的故障定位算法不再适用.本文提出了一种能解决多电源复杂配电网多重故障定位(可含有馈线末端故障)的矩阵算法.该算法对于故障信息不完备和故障信息畸变的情况同样适用.算例测试结果验证了该方法的正确性和可行性,在配电网实时故障定位的应用中具有很大的潜力.     

配电网具有容错性的快速故障定位方法研究

为实现非健全故障信息下配电网的快速容错故障定位,提出在终端开辟空间储存采集的三相电流信息,并上传主站。故障后,主站利用配电网故障后各馈线开关上报的遥信量各相故障报警信号之间,遥测量三相故障电流之间以及三相故障电流与各相故障报警信号之间的相关性,对终端设备上报的存在漏报、误报的故障报警信号进行修正。然后,提出通过分析配电网的拓扑结构,将配电网划分为独立的最小配电区域,并提出了综合最小配电区域端点上报的校正后的故障报警信号,快速实现故障区段定位的方法。结合具体实例对所提算法进行了详细的说明,分析表明该算法能有效校正漏报、误报的故障报警信号,快速实现配电网故障区段的容错定位。     

A new single ended fault location algorithm for combined transmission line considering fault clearing transients without using line parameters

In this paper a new single ended fault location method is proposed for underground cable combined with overhead lines. In this algorithm fault clearing high frequency transients are used instead of fault-generated transients and the line parameters are not needed. In the proposed algorithm, samples just from voltage transients generated by fault clearing action of circuit breaker are taken from the sending end of the cable line. Applying wavelet transform, the first three inceptions of traveling waves to the fault locator are detected. Using these, the proposed algorithm at first identifies fault section, overhead or cable, and then wave speed is calculated and at last location of fault is determined accurately. Because of using only voltage samples taken from one terminal, it is simple and economic and does not need to GPS and data communication and synchronization. Extensive simulations carried out using SimPowerSystem toolbox of MATLAB, confirm the capabilities and high accuracy of the proposed method under different system and fault conditions.     

配电网故障区间定位的改进矩阵算法

分析目前配电网故障定位算法中存在的不足,结合配电网的结构特点,提出网络关系矩阵概念和用于故障定位的改进矩阵算法。该算法与之前的矩阵算法及其他改进矩阵算法相比,具有原理简单,无须复杂的运算且运算量小,实时性好的特点。不仅适用于单电源供电的简单配电网故障定位,也适用于多电源供电的复杂配电网故障定位。不仅可以快速准确地定位单点故障,也可以快速准确地定位多点故障。甚至各台柱上FTU上传主站的信号发生畸变时,仍能快速准确地定位故障,具有非常好的容错性能。实例分析和案例仿真表明该算法的可行性与准确性。     

多目标配电网故障定位的Pareto进化算法

提出一种用于配电网故障定位的多目标优化模型,采用带精英策略的快速非支配排序遗传算法(NSGA-Ⅱ)进行求解.传统多目标优化问题通过加权方式转换为单目标问题,对权值比较敏感,且每次只能得到一种权值下的最优解.NSGA-Ⅱ则避免了传统加权求解时权值的选择和解的偏好性.该算法采用快速非支配排序机制,计算复杂性低;同时考虑个体拥挤距离,从而保证种群的多样性;最后,提出适用于故障定位的最优解集处理方法,便于从多目标最优解集中筛选出唯一符合故障情况的解.算例测试分别模拟单点、多点故障,以及信息完备和部分信息畸变的情况,测试结果表明,所提方法均能准确地定位故障区段.