多分支配电网接地故障定位的特征向量法

在配电网接地故障定位传递函数法的基础上,提出了一种能够方便应用于多分支配电网接地故障定位的新方法——特征向量法。该方法利用数字信号处理手段获得具有一定分支结构的配电网的传递函数频谱特性,通过对频谱特性的进一步处理,获得故障线路中故障和分支的信息,并将这些信息转化为故障特征向量。对于某一固定分支结构的配电网,利用该方法建立各种故障特征的数据库,形成数据库专家咨询系统,以实现对多分支配电网接地故障的定位。     

基于GIS的配电网管理系统的建设与应用

中山供电局为了提高配电网管理水平,建设了基于地理信息系统(GIS)的配电网信息管理系统.该系统采用B/S和C/S结合的方式,将自动绘图 (AM)、设备管理(FM)、地理信息系统(GIS)和配电网管理信息系统(MIS)集成于一体,可对配电网进行自动分析,管理设备台帐、停电、检修、故障、巡检、规划等.实际运行表明,该系统不仅为配电网管理、计算、规划和分析提供了强有力的基础数据支持,而且简化了操作方式,提高了工作效率.     

计及开关和母线故障的配电系统可靠性评估

在中低压配电系统中，负荷点和系统的可靠性除了与线路的故障有关外，还与系统中各种开关、母线等元件的故障有关。文中给出了考虑开关和母线故障的配电系统可靠性评估程序的设计思路。采用故障模式及其后果分析方法（FMEA），对网络结构进行故障后果区域划分，找出与负荷点停电模式相关的不同元件集合，从而计算了负荷点的可靠性指标和系统的可靠性指标。该程序还采用了递归函数使能很方便地识别辐射型配电系统结构。通过对IEEE6母线可靠性测试系统（RBTS）及实际系统的可靠性计算，结果验证了该程序的准确性和实用性。     

基于RBFNN的高压断路器机械故障诊断系统

高压断路器是电力系统中最重要的控制和保护设备,其故障检修和诊断一直是电力运行部门高度重视的问题。为了提高高压断路器故障诊断的效率和准确率,提出了高压断路器机械故障诊断的径向基函数神经网络(RBFNN)方法;并根据其基本原理建立了高压断路器操动机构故障诊断的RBFNN模型;利用Matlab工具,使用来自现场的实际数据,通过故障诊断仿真实例,分析、验证RBFNN模型的性能,并对不同方法进行了对比分析。结果显示RBFNN训练速度快、逼近误差小,对输入输出关系比较复杂的高压断路器操动机构的故障诊断有很高的判断效率和准确率。     

Lightning-caused distribution circuit breaker operations

As a part of EPRI Research Project 2542-1, Characteristics of Lightning Surges on Distribution Lines, a coincident lightning events detector (CLED) was developed, tested, and installed in a test area on the Florida Power Company distribution system in St. Petersburg, Florida. The CLED provided the data to determine the number of lightning-caused circuit breaker operations for the first time. During the 3-year recording period, a total of 546 faults causing circuit breaker operations occurred on the seven circuits in the test area. Of these faults, 415 (or 76%) were temporary faults. A lightning strike was coincident with 42% of the temporary faults. Improper operation of line fuses was traced to the absence of lightning arresters at line fuse locations     

A new large scale DAS in CEPCO

The Chubu Electric Power Company (CEPCO) has developed the distribution automation system (DAS) by using minicomputers which monitor and control large and complex distribution networks with maximum reliability and promptness. A significant curtailment of the restoration operation time due to the occurrence of faults is expected by the introduction of the DAS. The authors introduce the DAS that was installed at CEPCO's Kita Utility Office in December 1989 and report on its operation performance. The objectives of the DAS are to enhance the reliability of the power supply, to improve the service quality for customers, and to improve the efficiency in facility utilization. The DAS connects the utility office online with the supervisory control and data acquisition (SCADA) system at the control center and the total distribution management system at the head office, and it has unique functions that will contribute to integrated distribution automation     

A logic programming approach to fault diagnosis in distribution ring networks

The prime objective in the operation of a distribution system is to supply power to the customers and to meet their load demands. Whilst the probability of fault in high voltage and extra high voltage networks is low, the chance of fault in distribution networks is relatively high. When a fault occurs in a distribution network, it must be identified and removed immediately so that power can be restored as soon as possible. This paper develops a logic model for diagnosing faults in distribution ring networks. Methods in the model for representing network configurations, faults, symptoms of faults and defects are presented. Fault-finding rules are developed from the relations between the faults and their symptoms, including the effects of hidden defects due to battery failures and open-circuited pilot-wire circuits in the feeder protection systems. A logic program is developed based on the logic model and it is implemented by a goal-directed language, Prolog. The power of the logic program system for fault diagnosis is demonstrated through its application to an 11 kV distribution network.     

Application of a system with distributed architecture for information acquisition and processing in tasks of active–adaptive voltage control in distribution electric grids

An active–adaptive control system for power grids with distributed architecture of data acquisition and processing is considered. The advantages of the proposed control principle are compared with commonly used methods. A domestic apparatus—a programmable recording bay controller (PRBC)—is described. This hardware was designed to measure the basic electrical parameters and create distributed systems for data acquisition and processing. The procedure is considered of supervisory control and data acquisition (SCADA) by the SONATA system based on a multicore distributed architecture having high reliability and supporting a rigid real-time mode. A full-function full-scale model of active–adaptive voltage control system (AAVC) was set up using proposed software and hardware. The AAVC makes it possible to use the results of calculating–measuring procedures to select a corresponding on-load tap-changer (OLTC) on the actual voltage levels in the nodes of distribution grid. This approach to centralized voltage control in distribution grids makes it possible to ensure the required level of voltage in the greatest possible number of power consumers owing to prediction of voltage change. The effect of emergencies (random failure of control equipment) during the operation of an active–adaptive voltage control system is analyzed. A qualitative evaluation of the effect of faults on regulation quality and choice of OLTC connection is carried out. It is shown that, for undisturbed operation of an active–adaptive voltage control system, additional diagnostic tools, backup, and data loss compensation are needed.     

小电流接地系统接地型早期故障扰动特征分析

早期故障用于描述系统中不会导致继电保护动作的瞬时性自恢复故障扰动。基于对早期故障扰动的检测识别可实现对配网的故障预测和预警,对于提升供电可靠性有重要意义。受中性点接地方式影响,小电流接地系统中早期故障将有不同表现形式。针对小电流接地系统特点及其运行要求,分别从等效电路及仿真建模两方面,对该类系统中接地型早期故障的表现形式及其电气量变化特征进行了分析和总结。结果表明,小电流接地系统中接地型早期故障分为"单相接地型"和"异名相两点接地型",同时总结了各种情况下早期故障扰动波形的变化特征。仿真和部分现场故障录波数据证明了分析结论的正确性,研究结论将为小电流接地系统早期故障检测识别及故障预测预警提供重要理论支撑。     

Adaptive centralized protection scheme for distribution systems with DG using risk analysis for protective devices placement

Conventional electric distribution systems are radial in nature, supplied at one end through a main source. These networks generally have a simple protection system usually implemented using fuses, re-closers, and over-current relays. Recently, great attention has been paid to applying Distributed Generation (DG) throughout electric distribution systems. Presence of such generation in a network leads to losing coordination of protection devices. Therefore, it is desired to develop an algorithm which is capable of protecting distribution systems that include DG, through diagnosis and isolation of faults. A new approach for the protection of distribution networks in the presence of DGs is presented in this paper. The algorithm is based on dividing an existing distribution network into several zones, each capable of operating in island operation. In the suggested method, risk analysis is used to optimize the protection zones by optimal placement of protective devices. Multilayer Perceptrons (MLPs) neural networks are used for determination of faults. The proposed scheme has been implemented on a selected part of a real distribution network of a large city and a MATLAB based developed software has been used to implement the proposed algorithm on the real network data.     

考虑天气影响的配电信息物理系统可靠性评估

电力与通信深度融合是配电网发展的趋势,而天气又是影响配电网可靠性最主要的要素之一,研究评估考虑天气影响的配电信息物理系统可靠性很有必要。首先,选取对电力元件故障和通信元件故障影响最大的天气要素,并对天气要素进行区间划分,构建适合分析电力元件故障和通信元件故障的天气状态模型;其次,结合配电网历史故障数据和历史天气数据,构建以天气状态为变量的电力元件故障概率模型和通信元件故障概率模型;接着,针对通信元件故障使得监视和控制失效而造成的后果评估,给出配电网失负荷量化分析方法;然后,综合考虑电力元件和通信元件故障,提出基于蒙特卡洛方法的配电网信息物理系统可靠性评方法;最后,在改进的IEEE 33节点测试系统进行仿真测试,验证了所提算法的可行性和有效性。     

通信和电网联合仿真的配电网局部异常因子故障辨识算法

信息系统传输故障、恶意攻击和物理系统故障都将威胁智能配电网的正常运行。现有研究未充分考虑信息系统与配电网融合造成的差异,特别是缺乏对信息系统故障与配电网物理故障进行统一辨识的方法。文中利用MATLAB和OPNET建立交互作用分析模型,对发生于信息物理系统中的故障进行定量分析;进而,提出基于多维尺度分析(multi-dimensional scaling,MDS)和局部异常因子(local outlier factor,LOF)的配电网故障辨识算法,实现信息系统故障和配电网物理故障的统一识别,以及对配电网故障区域和故障通信节点的定位。利用交互作用分析模型得到的仿真结果验证了对于智能配电网故障类型的分析,配电网物理故障和通信节点故障的辨识结果验证了本文算法的有效性。     

基于支持度-置信度-提升度的配网自动化系统数据挖掘算法及应用

受到通信或其它设备及配网二次回路故障、缺陷及运行单位人为修改的影响,本已庞大、复杂的配网自动化控制系统数据库的数据质量问题更为严重,数据不准确、不一致、不可靠等问题层出不穷。针对这一问题,文章设计了一种基于支持度-置信度-提升度框架的挖掘算法,从配网自动化控制系统历史数据库中低质量的海量数据中智能挖掘频繁项集,建立符合配网自动化动作逻辑的、具备整体一致性的强关联、强相关规则。文章以具体案例详细介绍了该算法的应用,并通过分析说明该算法不仅为建立客观、合理的配网自动化系统指标评价体系提供可靠、准确的数据挖掘方法以及科学的理论依据,而且可以为管理部门日常运行、管理、维护、消缺工作提供智能的判定工具,节约人力、物力及时间成本,具有很强的工程意义。     

基于配用电数据关联的中压配电网断线故障诊断方法

基于配用电信息系统数据和关联规则算法,提出一种诊断中压配电网分支线断线不接地故障的方法。通过分析相互关联的配用电信息系统数据,提出基于数据特征选择的关联规则挖掘方法,并通过卡方分裂算法将连续型特征量转换为布尔型特征量,同时采用MSApriori算法解决故障信息中的稀有项问题,然后在此基础上应用kulc准则消除冗余规则以形成约简的代表规则家族。以华东某地区配用电信息系统中的历史数据为依据进行实际算例分析,结果说明所提出的方法能够大量减少无效挖掘,显著提高效率和准确度,适用于中压配电网断线故障的在线诊断。     

A new method for discrimination of ground faults causes in distribution lines

Since most problems in distribution lines are ground faults, the technology to distinguish the causes in the distribution lines will be very useful in preventing faults beforehand or, at least finding any problems at an early stage. The waveforms of ground faults which were collected from data concerning problems in the distribution lines and ground fault experiment are analyzed. The technology which could predict classified groups drawn from the scale of I₀ (the waveform of ground fault current) and V₀ (the waveform of ground fault voltage), and both of them in the ground faults is studied. The results demonstrated that I₀ could be classified into three groups, that is, leaking ground faults are sine curve shaped, gap discharge ground faults are triangular, and intermittent discharge ground faults are needle shaped. Also, simulated equivalent impedance of the causes of ground faults by EMTP is calculated. Furthermore, the influence caused by the condition of the distribution lines is investigated. With these results, a technique is proposed which could predict the cause of problems in ground faults.     

基于海量数据的配电网运行分析系统架构与技术实现

灵活地分析和运用配电网多源异构数据,进行配电网故障的准确预测和潜在风险扫描,对实现配电网高效精准的运行分析决策很有意义。文中介绍了一种基于海量数据的配电网运行分析系统的整体架构和功能设计,通过应用实例展示了系统各模块的功能和运行分析结果。该系统集成电网地理信息、营销业务应用和配电自动化等系统数据,采用改进的机器学习算法和薄弱点辨识方法,扩展了目标配电网数据相关性分析、故障风险等级预测和薄弱点辨识的功能,有利于相关部门有针对性地提出相应技术和管理手段进行配电网运维检修工作,提高了现有配电网分析系统的科学性和实用性,为最终实现配电网运行分析的信息化、智能化、精益化奠定了基础。     

Artificial neural network based fault diagnostic system for electric power distribution feeders

This paper describes the development of a fast, efficient, artificial neural network (ANN) based fault diagnostic system (FDS) for distribution feeders. The principal functions of this diagnostic system are: (i) detection of fault occurrence, (ii) identification of faulted sections, and (iii) classification of faults into types, e.g. HIFs (high impedance faults) or LIFs (low impedance faults). This has been achieved through a cascaded, multilayer ANN structure using the back-propagation (BP) learning algorithm. This paper shows that the FDS accurately identifies HIFs, which are relatively difficult to identify with other methods. Test results are generated using the Manitoba Hydro 24 kV distribution feeder. These results amply demonstrate the capacibility of the FDS in terms of accuracy and speed with respect to detection, localization, and classification of distribution feeder faults.     

基于级联阈值决策的变压器故障模糊诊断法

为了解决最大隶属度原则不宜诊断多故障、阈值原则漏诊率和误诊率较高的问题,在提出级联阈值判断原则后构成了级联阈值决策的加权模糊识别法。该法研究各特征气体组分比值在变压器故障诊断中的不同地位,确定加权系数矩阵,并用统计法估计单故障现象的故障隶属度,得到评判矩阵。通过评判矩阵和级联法值判断原则诊断变压器故障,不但诊断单种变压器故障正确率较高,且诊断多种故障同时存在的变压器故障效果也较理想。     

电网雷害分布图研究

为能够直观反映电网雷害分布,从地闪时空分布基础数据出发,通过确定电网雷害危险电流区间研究确定雷害危险事件频次分布及其分级的评估体系,提出了电网雷害分布确定方法。以华北雷电监测网2003~2006年共计375.2万次地闪记录数据为例,结合华北500、220 kV电网典型耐雷水平及其雷害故障历史记录数据,用电网雷害分布统计方法,研制了华北电网雷害图;分析了华北电网雷害事件与雷害分布图相关性。结果表明,电网雷害分布图与电网雷害故障历史记录间有良好的线性相关性。     

配电系统电压衰减的概率评估方法

提出了一种用于配电系统电压衰减的概率评估方法。该方法的研究基础是对在配电网发生故障时,母线上的残余电压进行解析分析,并以线路的故障率为基础,应用概率方法估计母线电压在给定时间内下降至指定阈值以下的次数,从而为供电系统的供电安全和供电质量的分析提供依据。对所给实例进行仿真研究,并与常用方法(如故障位置法)进行比较。分析表明,本文方法所得结果可避免故障位置及数量的不确定性的影响,能使用于各种类型的配电网络、故障模式以及沿线路的不同故障分布。