Numerical algorithm for adaptive autoreclosure and protection of medium-voltage overhead lines

In this paper, a new numerical algorithm for medium-voltage overhead lines, autoreclosure, is described. The subfunction of the autoreclosure scheme that would inhibit the first shot after detecting a solid fault (as compared with an arc fault) is evaluated and presented. It is based on one terminal data processing and it is derived in the time domain. In the algorithm the fault nature (arcing or arcless fault) is estimated using linear least error squares estimation technique. The arc, occurring on the fault point during arcing faults on overhead lines, is included in the problem consideration. In addition, by introducing the prefault load current in the existing model, better algorithm performances and a more reliable adaptive algorithm for autoreclosure are achieved. The algorithm is derived for the case of three-phase symmetrical fault. The results of the algorithm testing through computer simulation are presented. Particularly the algorithm sensitivity to arc elongation effects, supplying network parameters, and processing of the signals in the presence of harmonics are tested and analyzed.     

Numerical algorithm for overhead lines arcing faults detection anddistance and directional protection

In this paper, an overhead lines protection numerical algorithm, based on one terminal data and derived in the time domain, is presented. The fault location, direction and its nature (arcing or arcless fault) are estimated using the least error squares technique. The faulted phase voltage is modeled as a serial connection of fault resistance and arc voltage, offering more sophisticated line protection. The algorithm can be applied for both ordinary and the high impedance faults detection, distance protection, intelligent autoreclosure, as well as for the purpose of directional relaying. The approach presented does not require the line zero sequence resistance as an input datum. The algorithm is derived for the case of the most frequent single-phase to ground unsymmetrical faults. The results of algorithm testing through computer simulation are given. The influence of remote infeed, fault resistance, higher order harmonies, power system frequency, network topology, line parameters and other factors are investigated and systematically presented. Finally, an example of real life data processing is given     

Time domain solution of fault distance estimation and arcing faultsdetection on overhead lines

In this paper a new numerical algorithm for arcing faults detection and fault distance estimation is presented. The solution is given in the time domain. It is based on the line terminal voltages and currents processing. A simple new mathematical model of arc voltage is introduced in the estimation. Thereby, the more accurate approach to fault location is derived, particularly for the close-in faults. The new algorithm can be utilized for blocking the automatic reclosing. The unknown model parameters, including the line resistance and inductance, fault resistance and arc voltage amplitude, are estimated by using the least error squares method. The new algorithm is successfully tested through computer simulation and laboratory tests     

On Time Domain Overhead Lines Numerical Protection

A new fault location numerical algorithm based on terminal data and derived in time domain is presented. The fault location and its nature (arcing or arcless fault) are estimated using Least Error Squares Technique. In the paper, the arc, occurring on the fault point, is included into the problem consideration. The algorithm is derived for the case of a three-phase symmetrical fault. The results of the algorithm testing through computer simulation and under laboratory conditions are given. The influence of higher-order harmonics is investigated and presented.     

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.     

Two-stage numerical algorithm for distance protection, fault location and arcing faults recognition

In this paper, a novel two-stage numerical algorithm devoted to fault distance calculation and arcing faults recognition is presented. The first algorithm stage serves for the fault distance calculation. The fault distance is calculated from the fundamental frequency phase voltages and current phasors, thus utilizing the positive- and the zero-sequence impedances of the line as input parameters. The second algorithm stage serves for the arc voltage amplitude calculation. It utilizes the fault distance calculated in the first algorithm stage as well as the third harmonics of the terminal phase voltage and line current phasors, respectively. From the calculated value of arc voltage amplitude it can be determined whether the fault is transient arcing fault or permanent arcless fault. The phasors needed for algorithm execution are calculated by using the Discrete Fourier Technique. In this paper, the solution for the most frequent phase-to-ground faults is given. The results of algorithm testing through computer simulation and real field data records processing are given.     

基于改进小波变换的故障电弧检测方法的研究

为了有效避免因故障电弧而引发的电气火灾,对故障电弧的故障检测进行了深入研究。故障电弧检测最常用的方法是小波变换,但是它存在着频谱混叠的问题。针对这一问题,提出一种基于添加节点前奇抽取的抗频谱混叠的改进小波变换算法,并利用多种负载进行验证,从而优化故障电弧检测,最后得到了准确度高、计算简单、实用性好的串联故障电弧检测方法。根据UL1699搭建了故障电弧实验平台,并基于此平台进行电弧发生实验。根据实验仿真结果的验证,改进小波变换解决了小波变换的频谱混叠问题,提高了故障电弧检测的精度,有效地减少故障误报率。     

故障电弧模拟测试系统及不确定因素的研究

针对低压系统故障电弧问题设计了一套故障电弧模拟测试系统,该系统含有上位机模块、下位机控制模块等,可以实现切割电缆、碳化路径及点接触3种类型故障电弧输出。同时,采用Logistic识别算法作为故障电弧保护电器检测的辅助判据。通过对系统中存在的不确定因素进行分析,选取切割电缆模块中的切割速度、电缆线径与电流幅值,以及点接触模块中的拉弧速度与接触面积作为主要影响因素进行研究。研究表明,在特定条件下电流零休时间会呈现趋势性变化,改变单一条件可使其变化1 ms左右。依据研究结果选取最合适的起弧条件,以提高故障电弧保护电器检测结果的准确性。     

一种断路器开断燃弧时间检测新方法

准确测量断路器燃弧时间的关键是确定电弧的起弧时刻.根据断路器开断时开断电弧的模型,详细分析了断路器开断前后电流的变化过程和开断相角等因素对燃弧时间的影响,提出了一种基于暂态电流的燃弧时间检测方法.通过对线路发生故障后的部分故障线路的三相电流录波数据滤波后进行拟合,预测之后的电流变化,并与实际电流数据比较,求得电流畸变量.当畸变量大于设定阈值时,即可认为该时间点为断路器的触头始分点;断路器首开相的触头始分点即起弧时刻.开断完成的时间点即熄弧点为相电流小于设定阈值的时间点,末开相的熄弧点为熄弧时刻.起弧时刻与熄弧时刻之间的时间差为断路器的燃弧时间.利用电磁暂态分析程序EMTP仿真证明了该方法的可行性和较高的可靠性.     

开关柜内部故障电弧探测法的研究现状及趋势

鉴于故障电弧是电力系统开关柜内部的灾难性故障之一,综合分析了国内外对故障电弧探测方法的研究及应用现状,在对现有各种故障电弧探测方法进行介绍和分析,指出各种探测方法的技术特点、局限性和适用范围的基础上,提出了故障电弧的早期预测预警探测方法及故障电弧探测算法智能化的发展趋势。通过研究和提取故障电弧放电前伴随的早期弧声、弧光的特征信息,实时在线监测该特征弧声、弧光是否存在即可断定故障电弧是否将会发生,从而改变了目前故障电弧的事后被动检测。可实现基于特征弧声、弧光的早期预测预警防护机制,把故障消除在发生早期,降低和避免了故障电弧产生时对开关设备造成的损失。     

基于Camberra距离的串联电弧故障诊断方法

为进一步降低低压电弧故障的误识率,针对串联电弧故障,提出一种基于脉冲信号变换的Camberra距离诊断方法。将负载电流转变为脉冲波,随机电弧故障表现出脉冲波的非周期波动。通过脉冲宽度的时间序列数值差分提取电弧故障的随机特征,构造出基于差分序列统计特性的故障特征向量。特征向量点值图呈现出明显的聚类特征。根据特征向量的Camberra距离分析结果与脉宽特征,给出电弧故障误识别问题的解决方法,确定了电弧故障的诊断算法。参考UL1699的电弧故障仿真试验和实际样机测试结果验证了该方法的可行性和较高的可靠性。     

A new approach to the arcing faults detection for fast autoreclosure in transmission systems

To avoid automatic reclosing on permanent faults, a new numerical algorithm for power transmission network arcing faults detection has been developed. Some important features of a long arc in air are investigated and used as a basis in the algorithm design. The fact that the nonlinear arc behavior influences other voltages and currents distorting them, offered an opportunity to detect the arc by measuring and processing the transmission line terminal voltage and current. A series of simulation studies have shown that the algorithm can be used as an effective tool for arcing faults detection.<>     

高压线路单相弧光接地对数仿真模型数据修正算法

受污闪、山火等因素影响,中性点接地高压输电线路易发生单相弧光高阻接地故障,但总体来讲现场获取的故障数据仍然严重不足,制约了弧光接地故障检测及保护技术的研究。人工弧光高阻接地故障实验成本较高,也难以普及应用。针对该问题,文中基于可直接表征电弧燃弧V-I特征的对数电弧模型,详细分析了该模型仿真数据和录波数据的差异性,针对该模型所表征出的电弧V-I特征未能反映实测录波数据中V-I相角差的问题,提出了一种对该模型仿真数据进行修正的数据处理算法,修正后的数据波形具有和真实录波V-I曲线更为接近的外特征,为后续弧光高阻接地故障的研究提供了数据支撑。     

基于高频重构信号与Bayes-XGBoost的低压电弧故障辨识方法研究

针对低压配电系统中单个用电负载支路串联电弧故障辨识困难的问题,提出一种基于高频重构信号和Bayes-XGBoost的低压电弧辨识方法。首先,搭建多支路、多负载类型的低压电弧故障真型实验平台,并采集相关数据。其次,基于故障前后主线路电流高频信号变化规律,提出信号微弱变化叠加法重构故障有效信号。最后,建立适用于单个负载支路电弧故障辨识的XGBoost模型,并采用Bayes算法对模型多个超参数进行优化。实验结果表明,所提方法在多种工况下对单个负载支路电弧故障具有较高的辨识准确率。与6种主流故障分析方法对比,所提方法在精度、训练速度和泛化能力等方面展现出了显著的优越性,有利于实现低压配电系统单个负载支路电弧故障的可靠辨识。     

Spectral domain arcing fault recognition and fault distance calculation in transmission systems

A new numerical algorithm for recognizing arcing faults for the purpose of automatic reclosing is presented. The fault distance can also be calculated using this algorithm. The solution for both symmetrical and unsymmetrical faults is given. A simple empirical arc voltage model is obtained through a table of numerical values. By means of computer simulation and laboratory testing it is shown that the algorithm can be used as an effective tool in transmission and distribution system protection.     

Overhead lines fault location and arc voltage estimation numerical algorithm derived in time domain

Contents A new fault location numerical algorithm based on terminal data and derived in time domain is presented. The fault location and its nature (arcing or arcless fault) are estimated using least error squares technique. The faulted phase voltage is modelled as a serial connection of fault resistance and arc voltage. The new approach does not require the line zero sequence resistance as an input datum. In the paper some important features of arc voltage are given. The algorithm is derived for the most frequent case of single-phase line to ground unsymmetrical fault. The results of algorithm testing by computer simulation and under laboratory conditions are given. The influences of remote infeed, fault resistance, higher order harmonics, network topology and other factors are investigated and presented.

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Lichtbogenspannung und Fehlerdistanz Schätzung in Freileitungsnetzen mittels im Zeitbereich entwickelten numerischen Algorithmus

Übersicht In diesem Aufsatz wird ein neuer numerischer Algorithmus dargestellt der im Zeitbereich entwickelt ist, und der als Eingabe die Daten einer Meßstelle am Leitungsanfang verwendet. Mit dem Algorithmus werden die Fehlerdistanz und die Art des Kurzschlusses(Lichtbogenkurzschluß, Kurzschluß ohne Lichtbogenwiderstand) bestimmt. Dabei wird die Methode der kleinsten Fehlerquadrate verwendet. Die Spannung an der Fehlerstelle wird als eine Reihenschaltung aks omschem Widerstand und Lichtbogenspannung nachgebildet. Das neue Verfahren benötigt nicht den Nullwiderstand der Freileitung, dessen Bestimmung oft ungenau ist, als Eingabe. Die wichtigsten Eigenschaften des Lichtbogens werden auch angegeben. Der Algorithmus wird entwickelt für den häufigsten Fall des einpoligen Fehlers und getestet anhand von Simulationsrechnungen und im Hochspannunglabor. Der Einfluß der Art der Einspeisung, der Ober, des ohmschen Fehlerwiderstands, der Topologie des Freileitungsnetzes und anderer wichtiger Faktoren wird untersucht.

     

New Digital Algorithm for Adaptive Reclosing Based on the Calculation of the Faulted Phase Voltage Total Harmonic Distortion Factor

This paper presents a new numerical algorithm suitable for determining adaptive dead time, and blocking automatic reclosing during permanent faults on overhead lines. It is based on terminal voltage input data processing. The decision if it is safe or not to reclose is determined by the voltage signal of faulted and tripped line phase using the total harmonic distortion factor calculated by discrete Fourier transform. The algorithm was successfully tested using signals recorded on the real power system. The tests demonstrate the ability of the presented algorithm to determine the secondary arc extinction time and to block unsuccessful automatic reclosing of high-voltage lines with permanent fault     

Effective Two-terminal Numerical Algorithm for Overhead Lines Protection

In the paper an effective numerical algorithm for overhead lines protection, particularly fault location and adaptive autoreclosure, is presented. It is based on the two terminal line currents and voltages acquisition. For this purposes the synchronized sampling of all analogue input variables, i.e. the application of the Global Position System/Phasor Measurement Units, was assumed. The algorithm presented is derived in the spectral domain. By this the set of third harmonics variables and line parameters was also used. The prerequisite for successfully adaptive autoreclosure functionality realization was the suitable modelling of the electrical arc. Arc was considered as a source of higher harmonics, distorting by this other electrical variables. In the arc modelling, results of laboratory testing were used. Algorithm is tested for a typical network configuration, assuming by this that the line considered was short enough to neglect its capacitive nature. Based on the results obtained, it is very realistic that the algorithm presented could be implemented in praxis in modern Intelligent Electronic Devices (IEDs).     

电弧反射电缆故障测距装置脉冲发射时刻选择算法

电弧反射法(ARM)是一种广泛应用的电缆故障测距方法.由于不清楚测试过程中电缆故障点电弧电阻的动态特性,因此施加测试脉冲时脉冲发射时刻的选择比较困难.分析了ARM测距装置放电过程中的电压和电流特性,以及故障点的电弧电阻特性.论证了在直流电弧放电阶段电弧电阻较低而且稳定,是发射脉冲的最佳时段.据此提出根据电流最大值和故障...     

基于多信息融合的故障电弧保护系统的应用研究

在以故障电弧弧声、弧光、短路电流为表征信息的基础上,提出了一种新的电弧保护方案。以发生燃弧之前的弧声为判据,建立了故障电弧预警机制;以燃弧伴生信号弧光、短路电流为判据,建立了故障电弧的报警机制。实验表明,该系统可以对开关柜的故障电弧起到双重保护作用。