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.     

An approach for simultaneous distribution,sub-transmission,and transmission networks expansion planning

Sub-transmission network, as an intermediate grid between the distribution and transmission systems, receives the electric energy from the transmission network at extra high voltage levels, and delivers it to the distribution network at medium or low voltage levels. The adequate design and operation of sub-transmission system will lead to an efficient design of transmission network from the technical and economic viewpoints on one hand and the adequacy of power delivery to the distribution loads on the other hand. Therefore, the design optimality of these three networks is highly dependent on each other. However, as the simultaneous design of distribution, sub-transmission, and transmission systems is highly complicated, very few researches have tried to model and solve such a difficult problem. In this paper, a new approach has been developed for simultaneous distribution, sub-transmission, and transmission networks expansion planning. The proposed approach has been formulated as an optimization problem where an efficient and improved genetic algorithm (GA) is employed to solve such a complex problem. The utilized GA has been equipped with different modifying operators in order to make sure of its appropriate performance in obtaining useful and optimal solutions for the coordinated planning problem. The conducted approach has been implemented on a real network of Zanjan Regional Electrical Company (ZREC), and the results are compared with those of conventional method, i.e. separate expansion planning of these networks. The simulation results demonstrate the effectiveness of the conducted approach.     

A basic framework for sub-transmission system health analysis

The reliability of supply in sub-transmission systems is usually quantified in terms of two sets of indices, the individual supply/load point indices (average failure rate, average outage duration and average annual unavailability) and the system performance indices (SAIFI, SAIDI, CAIDI, ASUI, ASAI, etc.). These probabilistic indices are very useful not only for assessing the severity of system failures in future reliability predictions but also in assessing the system’s past performance. Many utilities, however, continue to use deterministic methods (rule-of-thumb methods) to assess the reliability of their systems. This paper presents a method designated as system well-being analysis, which in addition to the conventional probabilistic risk index of supply point unavailability, also incorporates the specified deterministic criteria in defining additional system healthy and marginal states. The proposed method is illustrated in this paper to calculate the well-being indices of electric sub-transmission systems. The proposed technique, which can be used to evaluate the adequacy of sub-transmission systems, is applied in this paper to a small but comprehensive test system to show the effects of some pertinent factors and deterministic criteria on the system well-being indices.     

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.     

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。     

一种配电网故障阶段式恢复方法

为快速确定配电网故障恢复的最优方案,提出了一种将启发式规则与优化算法相结合的故障阶段式恢复方法。各个阶段通过指标判定是否执行,不同故障的恢复阶段不同。第一阶段采用启发式搜索方法恢复网络连通性;第二阶段利用和声算法以电压不越限及线路不过载为目标进行重构;第三阶段基于深度优先搜索法及负荷优先级切负荷;第四阶段利用和声算法进行网损优化重构。为快速分析配电网的拓扑结构,提出单联络回路的概念,不仅可用于快速恢复故障后网络的连通性,而且可为优化算法避免拓扑不可行解编码提供理论基础,有效提高了运算效率。通过仿真验证了所提方法的可行性。     

A fault diagnosis expert system for distribution substations

This paper presents a practical expert system for the diagnosis of various faults which may occur in distribution substations. The backward inexact reasoning process is applied for the fault section estimation using the knowledge of topology, the operation rules of protective devices, heuristic knowledge of well-trained operators, and instantaneous alarms. In this paper, the overall structure, detailed knowledge-base and the efficiency of general methodology based on topology are discussed. The proposed system has been tested in a local control center in Korea as a part of an intelligent guidance system for the SCADA operators     

配电网故障自动定位技术研究综述

根据已有的研究成果,对配电网故障自动定位技术研究涉及的主要内容,即故障选线、区段定位、故障测距进行了综述。故障选线是为了识别判断母线多条出线中的故障线路,其主要包括：基于外加注入信号的故障选线,基于故障稳态量、暂态量和综合式故障选线等。区段定位旨在迅速隔离故障并恢复非故障区域供电,主要研究包括：基于现场设备采集的故障实时信息、基于故障投诉电话等定位方法以及故障特征微弱时的故障识别判断。故障测距的目的是直接定位出故障位置,其主要包括：注入法故障测距、基于稳态量故障测距和基于暂态量故障测距。结合配电网故障自动定位技术及最新研究成果,对其发展方向进行了展望。     

配电网生产管理信息系统

文章给出了一个由MIS和GIS相结合的配电网生产管理信息系统.介绍了用来完善MIS系统功能的GIS系统的相关技术以及主要功能,并描述了此系统的特色.实际使用表明,地理信息系统技术对于传统的电力工业有着积极的作用.     

A real-time operation analysis system for distribution networks

This paper describes the functional aspects and characteristics of a real-time operation analysis system, called interplan operation (IO), operating in the distribution operation center (COD), AES Sul Distribuidora Gaúcha de Energia, in São Leopoldo, RS, Brazil. Among the main characteristics of the system is the integration between different types of information from distinct databases, as reference files, measurements, events, maintenance crews, and operation information. With the user-friendly interface and graphic access to data basis, operation, and calculation information, interplan operation has been proven a flexible, well-built system, efficient in operation analysis for decision-making. The system is composed by several technical modulus embedded into the system, as the optimized switching module, based on a genetic algorithm of specific and innovating characteristics to solve problems. This module is the result of the research and development program carried out in AES Sul.     

配电网生产管理信息系统

文章给出了一个由M IS和G IS相结合的配电网生产管理信息系统。介绍了用来完善M IS系统功能的G IS系统的相关技术以及主要功能,并描述了此系统的特色。实际使用表明,地理信息系统技术对于传统的电力工业有着积极的作用。     

Hybrid classifier for fault location in active distribution networks

This paper presents a fast hybrid fault location method for active distribution networks with distributed generation (DG) and microgrids. The method uses the voltage and current data from the measurement points at the main substation, and the connection points of DG and microgrids. The data is used in a single feedforward artificial neural network (ANN) to estimate the distances to fault from all the measuring points. A k-nearest neighbors (KNN) classifier then interprets the ANN outputs and estimates a single fault location. Simulation results validate the accuracy of the fault location method under different fault conditions including fault types, fault points, and fault resistances. The performance is also validated for non-synchronized measurements and measurement errors.     

中心城区配电网DSCADA配置方案探讨

针对城市配电网DSCADA目前存在的问题,探讨了配电自动化终端、通信系统及工作电源的配置要求和实施要点,并以小陆家嘴地区DSCADA配置的实例,对中心城区DSCADA配置方式进行了分析.     

配电网故障处理若干问题探讨

为了提高配电网的故障处理性能,对配电网故障处理过程进行了归纳。对配电网继电保护配置、就地型馈线自动化改进以及单相接地故障处理等问题进行深入研究,指出配电网继电保护不必追求完美配合,只要效果明显就值得配置。论述了一种基于合闸速断方式的就地智能馈线自动化的改进方法,实例表明其不仅可以显著加快相间短路故障处理速度而且可以做到免整定。论述了智能接地配电系统的组成和工作原理,讨论了暂态过程抑制、选相容错纠错和单相接地选线定位与隔离等关键技术的实现方法。     

城市配电网柔性互联系统故障重构研究

柔性电力电子开关(Soft Normally Open Point,SNOP)用于替代传统配电网中的联络开关,文中对SNOP单侧交流系统故障后进行恢复重构研究。SNOP在配电网故障后可提供电压支撑作用,在配电网故障恢复重构研究时,除了要考虑系统运行约束条件外,还需考虑SNOP的运行特性。文中首先建立了SNOP的潮流稳态模型;通过牛拉法潮流计算去掉不符合系统运行约束条件的开关组合;然后以二进制粒子群算法(Binary Particle Swarm Optimization,BPSO)为基础,建立以重要失电负荷最少、网损最小、开关操作数最少为目标函数,设置潮流、电压、电流等约束条件,寻求故障重构的最优开关组合。最后以两个IEEE33节点算例互联为例用matlab仿真,验证所建立模型和算法的可行性。     

Dynamic sub-transmission system expansion planning incorporating distributed generation using hybrid DCGA and LP technique

Since the emerging of distributed generation (DG) technologies, their penetration into power systems has provided new options in the design and operation of electric networks. In this paper, DG units are considered as a novel alternative for supplying the load of sub-transmission system. Thus, the mathematical model of considering DG on the expansion planning of sub-transmission system is developed. Fix and variable costs of the plan and the related constraints are formulated in the proposed model. The proposed objective function and its constraint are converted to an optimization problem where the hybrid decimal codification genetic algorithm (DCGA) and linear programming (LP) technique are employed to solve it. Solution of the proposed method gives the optimal capacity of substations; optimal location and capacity of DGs as well as optimal configuration of the sub-transmission lines. To demonstrate the effectiveness of the proposed approach, it is applied on a realistic sub-transmission system of Zanjan Regional Electrical Company, Iran, and the results are evaluated.     

基于故障分量原理的配电网高阻接地故障检测方法

配电网中发生高阻接地故障时,短路电流小于传统过流保护的阈值,无法被常规保护装置检测和清除。若不及时消除短路电路,极易演化成严重故障。针对该问题,文中首先分析发生高阻接地故障时配电网的故障分量特征和基于母线处的正序电压故障分量与其相连接的各馈线正序电流故障分量的相位差特征,给出适用于配电网高阻接地故障检测的故障判据。然后,为解决配高阻接地故障检测过程中系统不平衡引起的一系列问题,制定了相应的故障检测启动判据。基于该故障检测判据和启动判据,制定基于故障分量原理的配电网高阻接地故障检测方法。最后,在PSCAD/EMTDC仿真软件中建立含架空线路的中压配电网模型,仿真结果验证了所提高阻接地故障检测方法的正确性。     

A diagnostic method for distribution networks based on power supply safety standards

In order to overcome the shortages of diagnostic method for distribution networks considering the reliability assessment, this paper proposed a method based on power supply safety standards. It profoundly analyzed the security standard of supply for urban power networks, and established quantitative indicators of load groups based on different fault conditions. Then a method suitable for diagnostic evaluation of urban distribution networks in China was given. In the method, “N-1” calibration analysis of the distribution network was conducted. Then the results are compared with quantitative indicators of load groups on different conditions deriving the diagnostic conclusions and the standard revision is discussed. The feasibility and accuracy of the method is finally verified in the case study.     

城市电网智能调度故障辅助决策系统设计开发

介绍了一种可应用于城市电网调度部门的故障辅助决策系统软件,该软件通过故障诊断、故障恢复以及决策信息可视化三个环节辅助调度员进行事故处理决策。故障诊断环节通过分层处理故障信息,保证了故障定位区段的准确性。故障恢复环节通过有针对性的制定故障恢复方案评价指标,提高了故障恢复决策的合理性。决策信息可视化环节在海量故障信息中筛选出调度员真正需要的信息进行显示,提供了直观有效的辅助决策展示。该软件充分考虑调度员的决策需要,在某城市电网地调平台的应用测试验证了软件设计的可行性。     

电网故障诊断系统的一种设计与实现

电网故障诊断是保证电力系统安全稳定运行的重要手段。针对我国目前电网自动化水平的具体情况 ,提出了基于开关跳闸信号、保护信息及故障录波信息的分层式故障诊断方法。用此种方法诊断 ,不仅可以诊断简单故障和复杂故障 ,而且还可以诊断故障类型、故障相别 ,并完成故障测距 ,为运行人员迅速切除故障提供了可靠的保证