行波相关法的输电线路故障定位

This paper introduced correlation method to locate transmission line fault.First it described the principle of transmission line fault location based on traveling waves.The principle of correlation analysis is introduced,then the method using correlation analysis in fault location is given.Transmission line model is established with EMTP-ATP.Basing on the model,some kinds of fault are simulated.The feasibility of this algorithm is proved based on simulation results.By comparing with the classical wavelet analysis,this paper gave the advantages of this algorithm in two cases:noise influence suppression and accuracy of near distance fault location.Experiment is established to simulate transmission line grounding fault.The experiment result showed the correlation algorithm’s validity.All the analysis result indicated that the correlation algorithm have a high precision.     

基于故障点电压的单相自适应重合闸判据

A new adaptive single-pole autoreclosure technique based on the magnitude of fault point voltage is presented.After fault phase tripping,the fault point voltage of transient faults is essentially different from that of permanent faults,so the magnitude of fault point voltage is used to distinguish fault nature.Fault point voltage can be calculated through uniform transmission line equation.Considering that fault point voltage changes with fault location and transition resistance,a concept of real-time action voltage setting is put forward.The technique solves the problem that criterions based on terminal voltage could be easily affected by inductive coupling voltage and transition resistance.Simulation results show that the method is reliable.     

Robust fault analysis in transmission linesusing Synchrophasor measurements

As more electric utilities and transmission system operators move toward the smart grid concept, robust fault analysis has become increasingly complex. This paper proposes a methodology for the detection, classification, and localization of transmission line faults using Synchrophasor measurements. The technique involves the extraction of phasors from the instantaneous three-phase voltages and currents at each bus in the system which are then decomposed into their symmetrical components. These components are sent to the phasor data concentrator (PDC) for real-time fault analysis, which is completed within 2–3 cycles after fault inception. The advantages of this technique are its accuracy and speed, so that fault information may be appropriately communicated to facilitate system restoration. The proposed algorithm is independent of the transmission system topology and displays high accuracy in its results, even with varying parameters such as fault distance, fault inception angle and fault impedance. The proposed algorithm is validated using a three-bus system as well as the Western System Coordinating Council (WSCC) nine bus system. The proposed algorithm is shown to accurately detect the faulted line and classify the fault in all the test cases presented.     

带并联电抗器的交流特高压输电线路单相自适应重合闸故障识别方法(英文)

In order to avoid single-phase adaptive reclosure overlap in a permanent fault,accurate identification of the fault types on transmission line is necessary.We present a fault nature identification method for ultra-high voltage alternating current(UHVAC) transmission lines with shunt reactor.The voltage amplitude ratios of the neutral small reactance voltage to terminal voltage under transient fault and permanent fault are calculated.The significant differences of the ratio under the two faults have been analyzed.It is found that the ratio can be a criterion to distinguish the fault type,transient or permanent,accurately.Additionally,we also proposed a method that delays a beat frequency oscillation cycle to decide the fault types for the existence of beat frequency oscillation which will cause misidentification on transient faults.Abundant simulation results of ATP/EMTP show that the voltage amplitude ratio under transient fault is between 0.6 and 0.7,which is bigger than 2.5,the ratio under permanent fault.     

FAULT LINE SELECTION BASED ON CURRENT TRAVELING WAVES AND WAVELET TRANSFORM FOR NON SOLID GROUNDED SYSTEM

Detection and selection of singlephasetoground fault in distribution system with nonsolidgrounded neural are difficult. A new principle based on transient current traveling waves is presented to solve the problem. Through comparing the first current travelling waves of different lines at the bus bar, the fault line, whose first current travelling wave is of the reverse polarity and higher amplitude, is selected. In order to clearly recognize the traveling wave signal generated by fault, a new analysis tool, the wavelet transform is adopted. The new principle is also suitable for application to distribution and transmission system with solid grounded neutral. Extensive theoretical studies and simulations using EMTP have proven the feasibility of the proposed fault line selection method.     

基于粗糙集理论的配电网故障诊断规则提取方法

As the first step of service restoration of distribution system,rapid fault diagnosis is a significant task for reducing power outage time,decreasing outage loss,and subsequently improving service reliability and safety.This paper analyzes a fault diagnosis approach by using rough set theory in which how to reduce decision table of data set is a main calculation intensive task.Aiming at this reduction problem,a heuristic reduction algorithm based on attribution length and frequency is proposed.At the same time,the corresponding value reduction method is proposed in order to fulfill the reduction and diagnosis rules extraction.Meanwhile,a Euclid matching method is introduced to solve confliction problems among the extracted rules when some information is lacking.Principal of the whole algorithm is clear and diagnostic rules distilled from the reduction are concise.Moreover,it needs less calculation towards specific discernibility matrix,and thus avoids the corresponding NP hard problem.The whole process is realized by MATLAB programming.A simulation example shows that the method has a fast calculation speed,and the extracted rules can reflect the characteristic of fault with a concise form.The rule database,formed by different reduction of decision table,can diagnose single fault and multi-faults efficiently,and give satisfied results even when the existed information is incomplete.The proposed method has good error-tolerate capability and the potential for on-line fault diagnosis.     

A Novel Fault Location Algorithm for Double-Circuit Transmission Lines based on Distributed Parameter

1 IntroductionWith the development of the power system,thedouble circuit transmission lines have been widely used.The increased complexities of power transmission systemmake the transmission line fault location studies morecomplicated and important.The fault location for thesemore complex lines has raised great attentions.Differentfault location algorithms can be developed depending onthe extracted data from one or both ends of thetransmission lines.The method using one end data isaffected by…     

基于小波神经网络和D-S证据理论的电力变压器故障诊断研究

>Transformer faults are quite complicated phenomena and can occur due to a variety of reasons.There have been several methods for transformer fault synthetic diagnosis,but each of them has its own limitations in real fault diagnosis applications.In order to overcome those shortcomings in the existing methods,a new transformer fault diagnosis method based on a wavelet neural network optimized by adaptive genetic algorithm(AGA)and an improved D-S evidence theory fusion technique is proposed in this paper.The proposed method combines the oil chromatogram data and the off-line electrical test data of transformers to carry out fault diagnosis.Based on the fusion mechanism of D-S evidence theory,the comprehensive reliability of evidence is constructed by considering the evidence importance,the outputs of the neural network and the expert experience.The new method increases the objectivity of the basic probability assignment(BPA)and reduces the basic probability assigned for uncertain and unimportant information.The case study results of using the proposed method show that it has a good performance of fault diagnosis for transformers.     

A simple decision tree-based disturbance monitoring system for VSC-based HVDC transmission link integrating a DFIG wind farm

Fault detection and classification is a key challenge for the protection of High Voltage DC (HVDC) transmission lines. In this paper, the Teager–Kaiser Energy Operator (TKEO) algorithm associated with a decision tree-based fault classi f ier is proposed to detect and classify various DC faults. The Change Identification Filter is applied to the average and differential current components, to detect the first instant of fault occurrence (above threshold) and register a Change Identified Point (CIP). Further, if a CIP is registered for a positive or negative line, only three samples of currents (i.e., CIP and each side of CIP) are sent to the proposed TKEO algorithm, which produces their respective 8 indices through which the, fault can be detected along with its classification. The new approach enables quicker detection allowing utility grids to be restored as soon as possible. This novel approach also reduces computing complexity and the time required to identify faults with classification. The importance and accuracy of the proposed scheme are also thor oughly tested and compared with other methods for various faults on HVDC transmission lines.     

基于分布参数模型的高压输电线路故障测距算法

输电线路故障定位一直是电力系统亟待解决的难题,快速准确的故障定位对电力系统有极为重要的意义,由于传统的单端法故障测距易受过渡电阻和对端肋增电流的影响,基于集中参数电路模型的故障测距算法又不适用于长线路测距,中提出一种只使用输电线路参数和２端电气量的基于分布参数电路模型的输电线路故障这位方法。并利用相模变化来减少实际线路的不换位和线路参数不平衡的影响,最后在模域求解故障距离。ＥＭＴＰ仿真结果表明,     

基于分布参数线路模型的精确故障测距算法

为消除负荷电流和线路模型不准确给双端量故障测距带来的影响,提出一种基于分布参数线路模型的精确测距算法。算法以均匀传输线的波动方程(长线方程)为基础,利用线路两端电压、电流的正序故障分量以及线路正序参数直接计算故障距离。算法无需故障类型判别,不受系统阻抗、故障电阻、负荷电流以及分布电容的影响。基于EMTP的数字仿真结果验证了该算法的正确性和高精度。     

基于分布参数模型的串联补偿双回线单线故障定位算法

对于装设串联补偿(串补)装置的输电线路,由于与串联电容并联的保护元件金属氧化物可变电阻(MOV)的非线性特征,使得串补线路无法直接使用常规的输电线路故障测距方法。为此,提出了一种基于分布参数模型的串补双回线故障定位算法。按照故障点相对于串补的位置分为两个子算法,利用从本端、对端推算得到的故障点处电压相等的特点,消去串补装置近故障一侧的电压,结合故障点处过渡电阻的纯电阻性和故障序网边界条件,构造故障定位函数。该方法不依赖串补装置模型,不受MOV非线性的影响,无需预知串补装置相对于故障的位置,同时不存在伪根判别问题。EMTDC/PSCAD和MATLAB仿真结果计算验证了该方法的正确性。     

Accurate fault location algorithm for double-circuit series compensated lines using a limited number of two-end synchronized measurements

This paper presents a new fault location algorithm for double-circuit series compensated lines based on synchronized phasor measurements. Only the sequence current phasors from both ends of the line and the sequence voltage phasors from one local end are taken as input, limiting thus the amount of data needed to be exchanged between the line terminals. In addition, the proposed algorithm does not utilize the model of the series compensation device, eliminating thus the errors resulting from modeling such devices. The new algorithm consists of three steps. In the first step, the fault type and the circuit(s) involved in the fault are determined using a synchrophasor-based fault type selection method. In the next step, the algorithm applies two subroutines designating for locating faults on particular line sections which are defined according to the series compensation placement along the line. In these subroutines, the sequence voltages and currents at the fault point are expressed with respect to the known sequence voltages and currents at the two measuring ends and the distance to fault. Then, using the fault boundary conditions that exist for a given fault type, the fault location is solved by an iterative method. Finally, in the last step a procedure for selecting the valid subroutine is applied. Due to zero sequence mutual coupling, it is not straightforward to express the zero sequence voltage and current at the fault point as a function of the zero sequence voltages and currents at the measuring ends and the distance to fault. To overcome this problem, a modal transformation matrix is introduced to obtain the modal networks, which are decoupled and can be analyzed independently. Based on distributed parameter line model, the proposed algorithm fully considers the effects of shunt capacitances and thus achieves superior locating accuracy, especially for long lines. Mutual coupling between circuits, source impedances and fault resistance does not influence the locating accuracy of the algorithm. Simulation results using ATP-EMTP and MATLAB demonstrate the effectiveness and accuracy of the proposed algorithm.     

10kV或6kV直配线路单相接地故障测距的新算法

基于多导体传输线理论，针对配电线路的特点，提出了直配线路单相接地测距的新算法。大量的计算机仿真和于仿真线模型上的模拟故障诊断试验表明该算法有效。     

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。     

基于故障定位算法的配电网自动化

对配电网的故障定位问题进行了分析,针对我国配电网网络结构和基于FTU的馈线自动化自动控制模式的特点,提出了一种能适合树型配电网故障定位的新算法,建立了停电呼叫和故障诊断两种子算法模型,并通过一个实例算例证明了这种新的故障定位算法的可行性.     

基于双频法的树形配电线路单相断线兼接地故障诊断

针对树形配电线路特点，建立分布参数电路模型，利用故障后线路起始端的电压，电流相量，提出了树形配电线路单相断线兼接地故障定位新算法。本方法将始端相量逐分支向后传递故障点逐分支探索的方法实现故障测距，并利用双频法识别真伪故障。     

基于单端电气量的故障测距算法

本文提出了一种单端故障测距算法。根据零序电网不含负荷的特点，利用故障相电路和零序等值电路，推导出了一个精确的接地故障测距模型，消除了接地过渡电阻和对端运行状况的影响。本算法不同于以往的基于频域的正弦稳态算法．利用拉氏变换与Z-变换的关系，由频域变换到Z域，再进行Z反变换转换到时域，是一种基于时问域的测距算法。文章先对该方法进行了理论推导，然后利用EMTP对其进行数字仿真，结果证明了该算法的正确性。