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.     

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.     

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     

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。     

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     

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     

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.     

配电线路故障定位中的复阻抗在线测量系统

在配电网接地故障定位中,常常要对复阻抗进行在线测量。本文提出一种复阻抗在线测量系统的实现方案,采用DDS和可编程开关电容滤波器,保证了对50Hz电网谐波的滤除以及多频率下增益的稳定性,实现了多频率下对复阻抗的精确测量。     

A new and accurate fault location algorithm for combined transmission lines using Adaptive Network-Based Fuzzy Inference System

This paper presents a new and accurate algorithm for locating faults in a combined overhead transmission line with underground power cable using Adaptive Network-Based Fuzzy Inference System (ANFIS). The proposed method uses 10 ANFIS networks and consists of 3 stages, including fault type classification, faulty section detection and exact fault location. In the first part, an ANFIS is used to determine the fault type, applying four inputs, i.e., fundamental component of three phase currents and zero sequence current. Another ANFIS network is used to detect the faulty section, whether the fault is on the overhead line or on the underground cable. Other eight ANFIS networks are utilized to pinpoint the faults (two for each fault type). Four inputs, i.e., the dc component of the current, fundamental frequency of the voltage and current and the angle between them, are used to train the neuro-fuzzy inference systems in order to accurately locate the faults on each part of the combined line. The proposed method is evaluated under different fault conditions such as different fault locations, different fault inception angles and different fault resistances. Simulation results confirm that the proposed method can be used as an efficient means for accurate fault location on the combined transmission lines.     

A practical fault location approach for double circuit transmission lines using single end data

Double circuit transmission lines are frequently subjected to a variety of technical problems from the perspective of protection engineering. These problems are mainly due to the mutual coupling effects between adjacent circuits of the line. In this paper, a new fault location approach for double circuit transmission lines is introduced. It depends only on the data extracted from one end of the line. This practically facilitates implementing and developing this approach, as it needs no information from the other end. The approach is based on modifying the apparent impedance method using modal transformation. Depending on modal transformation, the coupled equations of the transmission line are converted into decoupled ones. This greatly eliminates the mutual effects resulting in an accurate estimation for the fault distance in a straightforward manner. Also the effects of prefault currents, charging currents, and the unknown fault resistance on the estimation accuracy are compensated. The proposed approach was tested via digital simulation using ATP-EMTP in conjunction with MATLAB. Applied test results corroborate the superior performance of the proposed approach.     

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.     

基于拓扑划分的配电网故障定位新算法

提出一种配电网故障定位的新算法,将配电网根据电源的个数进行分区,基于图论快速识别电网拓扑,将同一电源供电区域内的节点以树的形式进行链接。通过一次粗略定位找到存在故障的树,根据树中节点之间的链接关系,仅选择包含故障信息的支路,利用支路中父子节点故障信息的不一致性完成二次定位,准确找到故障的发生区段。用算例验证了所提算法的正确性和高效性。     

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.     

A fault location technique for rural distribution feeders

This work presents a digital fault location technique for rural distribution feeders, using the voltage and current data at a single location. Rural distribution feeders include single-phase, two-phase, and three-phase laterals off a main three-phase primary distribution feeder. The fault location scheme presented here attempts to account for the multiphase laterals, the unbalanced conditions, and the unsymmetrical nature of distribution feeders by continually updating voltage and current vectors at set locations within the system. The updated voltage and current vectors are the estimates of the 60-Hz phasor quantities obtained using a recursive optimal estimation algorithm. The distance to the fault is then estimated using a method based on the apparent impedance approach and the updated voltage and current vectors. Another consideration is the ability to determine the fault location on a lateral. A simulation of an actual rural distribution feeder using the Electromagnetic Transients Program (EMTP) is used to test the approach     

一种双端同步采样的时域故障测距算法

输电线路快速准确的故障定位是保证电力系统安全稳定运行的有效途径之一,对电力系统有重要意义.传统的单端故障测距算法易受过渡电阻及对侧助增电流影响,而双端故障测距算法一般基于频域的相量计算.提出一种基于模式理论和双端同步采样的时域故障测距算法.该算法所需传送数据量少,并且不受过渡电阻、运行方式、故障类型等因素的影响,并且可以将其推广到同杆并架双回线.EMTP仿真结果显示该算法有较高精度,测距快速简便.     

Comparison of impedance based fault location methods for power distribution systems

Performance of 10 fault location methods for power distribution systems has been compared. The analyzed methods use only measurements of voltage and current at the substation. Fundamental component during pre-fault and fault are used in these methods to estimate the apparent impedance viewed from the measurement point. Deviation between pre-fault and fault impedance together with the system parameters are used to estimate the distance to the fault point.     

基于故障分量的配电网单端量测距方法

为了消除负荷电流对配电网单相接地故障测距精度的影响,提出了基于故障分量的单端量测距方法.该方法根据横向故障电流的特征构造了测距函数,利用线路单端电压、电流的故障分量来计算故障距离.大量的ATP-EMTP仿真结果表明该方法不受负荷电流的影响,可以有效地搜索到配电网多分支线路的故障点或故障范围.     

基于图像匹配的电路板故障检测与定位算法

自动光学检查是利用图像处理算法进行电路板故障检测与定位的技术,它可以解决传统电路板测试无法克服的缺陷.图像相减是自动光学检查中最简单和最直接的办法,但具有一定的局限性,这是由于二值化预处理造成的.本文提出一种基于图像匹配的加载电路板故障检测与定位算法,无需进行二值化预处理操作,利用图像差的绝对值、平方以及相关操作,检测与定位元件的倒装与漏装故障,并具有与图像相减类似的简易性,实验证实了该算法的性能.     

A new algorithm for relaying and fault location based on autocorrelation of travelling waves

The technique employs correlation of the incident and reflected wave signals at one end of the line. Since the reflected wave is very similar in shape to the incident wave causing it, except for a constant time delay and attenuation, autocorrelation results. The property of ‘evenness’ of the autocorrelation is used to determine the delay time, which is a function of fault position, employing numerical integration which is suitable for a digital computer. It is shown that fast relaying as well as accurate fault location is accomplished on a real-time basis, even in the presence of a considerable amount of high frequency line transients. The technique has been tested by numerical simulations using the standard Electromagnetic Transient Program (EMTP).