Sequential tripping strategy for a transmission network back-upprotection expert system

This paper describes a sequential tripping strategy used in a wide area back-up protection expert system (BPES) to combat situations in which protection relays have maloperated or information is missing. The BPES is an innovative back-up protection scheme designed to prevent the occurrence of widespread blackouts. The BPES evaluates the certainty that transmission lines are likely to be affected by the fault and uses a sequential tripping strategy to isolate the fault if a firm decision is not available due to maloperated relays and/or missing information. The mode of analysis and the sequential tripping strategy ensures that the BPES will clear a fault at minimum risk to the network. An example is included to demonstrate how the certainty factor based sequential tripping strategy is employed by the BPES to clear a fault which occurred on the South Western part of the UK National Grid System     

基于网格平台的广域后备保护专家系统

传统的后备保护以单元件的保护为出发点,缺乏系统全局的观念。介绍了一种网格环境中的广域后备专家系统,它以保证整个输电线网络的稳定与安全为基础,从广域角度实现线路保护的目的。本文首先讨论了网格技术及其在电力系统继电保护中的应用,包括网格的基本概念和特点以及网格技术在广域后备保护中的应用前景;之后介绍了广域后备保护专家系统(BPES)的基本算法和系统结构。通过仿真,验证了其比传统后备保护的优越之处。     

基于负序功率方向比较原理的广域继电保护算法

提出一种基于负序功率方向比较原理的广域继电保护算法。根据智能电子设备（Intelligent Electric Device,IED）的安装位置,形成包含有母线及线路在内的IED关联域。系统发生故障后,通过IED在关联域内对故障信息的采集和共享,结合定义的故障判别原则,确定故障的位置;并根据IED预定的动作策略,快速地切除故障。该算法既能做系统发生故障后快速动作的主保护,同时又兼顾后备保护的功能。通过仿真验证了该算法的有效性,表明该算法可以很好地实现主保护和后备保护的功能。     

GOOSE方式变压器后备保护探讨

基于数字化变电站现阶段的技术条件,提出在变压器保护装置和与其相邻的保护装置中配置故障方向元件,通过通用面向对象变电站事件(GOOSE)方式交换各自就地测量的故障方向信息,共同实现变压器后备保护功能.在变压器主保护拒动各种工况下,探讨了GOOSE方式变压器后备保护的动作策略.研究表明保护新方法具有自适应性强、智能开关能与...     

基于贝叶斯网络的广域后备保护故障诊断检测

提出一种针对广域后备保护特征要求的贝叶斯网络线路故障诊断方法,根据保护动作和断路器跳闸信号,建立了面向元件的电网线路故障诊断模型。该模型是由Noisy-Or,Noisy-And节点组成的贝叶斯网络。该故障诊断方法具有实时性和准确性和较强的容错能力等特点,满足广域后备保护特征对故障诊断实时性、准确性的要求。     

An spatiotemporal information system based wide-area protection fault identification scheme

The paper presents a synchronized phasor measurement based fast and accurate comprehensive wide area back-up protection scheme for transmission lines. The proposed scheme uses Koopman Mode Analysis (KMA) technique on fault current data obtained from Phasor Measurement Units (PMUs) for fault identification in back-up protection. The principal advantage of Koopman operator is that it is based on spatiotemporal information system (STIS). In real world applications, often time and space exists together and hence, dealing with spatial aspect without considering temporal aspect is of limited use. The wide area back-up protection scheme is developed using STIS for fault identification and classification including wide variations in operating conditions of the power network. The New England 39 bus system is used as the test system which is developed on Dig-Silent power factory commercial software (PF4C) platform for evaluating the performance of proposed technique. Further, the efficacy of the proposed scheme is also tested for stressed conditions such as symmetrical fault during power swing and load encroachment and found to work effectively.     

电力市场环境下后备保护动作的经济性评估及责任承担

后备保护动作有可能导致故障切除设备和故障设备分属不同的市场参与者，从而影响到经济上相互独立的不同公司的经济利益。该文分析了现有的远后备保护和近后备附加断路器失灵保护的后备保护动作切除故障的3种后果：只对故障设备所属公司本身产生影响；对另一相关公司产生影响；对另一相关公司产生影响并进而影响该相关公司对其他公司的售（购）电情况，文中给出了后备保护不同配置方式下动作后果的经济性评估方法；提出了由故障设备所属公司各自承担责任，后备保护动作区内各公司互相承担责任及补贴承担责任等3种后备保护经济责任承担的模式，供当前厂、网分开的电力系统中后备保护动作造成的经济责任分担时参考。     

New development in relay protection forsmart grid

This series of papers report on relay protection strategies that satisfy the demands of a strong smart grid. These strategies include ultra-high-speed transient-based fault discrimination, new co-ordination principles of main and back-up protection to suit the diversification of the power network, optimal co-ordination between relay protection and auto-reclosure to enhance robustness of the power network. There are also new development in protection early warning and tripping functions of protection based on wide area information. In this paper the principles, algorithms and techniques of single-ended, transient-based and ultra-high-speed protection for EHV transmission lines, buses, DC transmission lines and faulty line selection for non-solid earthed networks are presented. Tests show that the methods presented can determine fault characteristics with ultrahigh- speed (5 ms) and that the new principles of fault discrimination can satisfy the demand of EHV systems within a smart grid.     

电力系统广域继电保护研究综述

分析了传统继电保护在保障电网安稳运行时存在的问题,对基于广域信息的继电保护研究涉及的主要内容进行了综述,包括:在线自适应整定、潮流转移识别、基于故障元件识别的广域后备保护.在线整定的目的是根据系统运行方式的变化,调整保护定值至最佳状态.计及的运行方式变化包括:电力设备投退、发电机出力与负荷变化等.潮流转移识别旨在防止传统后备保护的不适当动作引发电网连锁跳闸事故,主要方法有:支路开断前后输电断面的有功潮流比较、相邻支路电流比较.广域后备保护利用电网多点量测信息确定故障元件的具体位置,从根本上克服了传统后备保护整定复杂、可靠性低的问题.主要研究包括:基于传统主保护理论的故障识别算法、广域信息的容错性算法.最后,提出了以基于故障元件识别的广域后备保护为基础,构建面向智能电网的广域继电保护系统,并对其发展方向进行了展望.     

New development in relay protection for smart grid

This series of papers report on relay protection strategies that satisfy the demands of a strong smart grid. These strategies include ultra-high-speed transient-based fault discrimination, new co-ordination principles of main and back-up protection to suit the diversification of the power network, optimal co-ordination between relay protection and auto-reclosure to enhance robustness of the power network. There are also new development in protection early warning and tripping functions of protection based on wide area information. In this paper the principles, algorithms and techniques of single-ended, transient-based and ultra-high-speed protection for EHV transmission lines, buses, DC transmission lines and faulty line selection for non-solid earthed networks are presented. Tests show that the methods presented can determine fault characteristics with ultrahigh-speed (5 ms) and that the new principles of fault discrimination can satisfy the demand of EHV systems within a smart grid.     

基于故障匹配度的广域后备保护新原理

提出一种基于故障匹配度的广域后备保护新方法.该方法在系统正常运行时,根据系统拓扑和相量测量单元(PMU)的配置情况,形成保护关联域.系统发生故障后,通过分析各关联域内差动电流故障稳态分量,界定故障关联域,计算该关联域内的故障匹配度,并据此确定具体的故障位置.采用新英格兰10机39节点系统的分布参数模型进行仿真验证,结果表明该方法不受系统运行方式的影响,能够在PMU有限测点情况下快速、灵敏、可靠地实现故障定位,且在定位过程中无需修改系统矩阵,计算量小,易于实现.     

含分布式电源的配电系统保护方案

介绍了分布式电源接入配电系统后,采用基于两相电流差的自适应速断电流保护与无通道保护相配合的方案,即故障发生后先采用自适应速断电流保护。由于自适应速断存在保护死区,故以无通道保护作为后备保护。最后,通过对220 V配电系统进行仿真,验证了该保护方案的有效性。     

配电网馈线终端的智能化技术

馈线自动化系统是配电网系统的重要环节,本文从配电网系统及馈线自动化系统的分析出发,分析研究基于多Agent系统(MAS)网络式保护的FTU馈线自动化模式。FTU的设计基于Agent技术,构成MAS,其基于专家系统的故障判断模块,能够针对馈线的不同故障采取有效的保护措施实施馈线保护。     

变压器自适应相间后备保护

降压变压器高压侧过流保护对低压侧区内故障不能保证灵敏度,无法满足作为变压器内部相间短路近后备保护的要求;同样低压侧过流保护在相邻线路末端相间短路时也存在灵敏度不足问题,不能满足作为相邻元件远后备保护的要求。在分析自适应保护特点和变压器后备保护配置的基础上,提出了变压器自适应过流保护方案,它在故障时在线识别系统运行方式和故障类型,实时自动地计算变压器后备保护的整定值,在保证正常工作时不会误动的前提下,又确保了变压器区内、区外故障时作为近后备、远后备保护的灵敏度。文中通过算例证明了该自适应后备保护方案的优越性和可行性。     

基于相邻变电站信息融合的广域后备保护系统

人工智能技术为广域后备保护容错性的研究提供了有力的技术平台。借助人工智能技术,文中提出了基于相邻变电站信息融合的广域后备保护算法,用于变电站集中式结构的后备保护。该保护系统收集所在变电站及相邻变电站内的各种主保护信息和后备保护信息,对获取的信息采取融合策略,构成遗传算法的适应度函数,通过遗传算法的最优搜索决策,纠正所在变电站内缺失或错误的信息。对IEEE 5机14节点系统的仿真结果表明,所提出的算法简单可行、可靠性高。     

A comprehensive method for break points finding based on expert system for protection coordination in power systems

Interconnected power systems are multi-loop structured. In such networks, the determination of settings for all overcurrent relays can be carried out in different forms and may be quite complicated. The main problem for coordination is the determination of starting points, i.e. the location of starting relays in the procedure for settings, which is referred to as break points. In this paper, a powerful approach based on expert system is applied. The rules of the expert system include network configuration, protection systems, fault levels, etc. The method is applied to two networks with different configurations, pilot protection and other protection systems. From the obtained results, it is reviled that the new method is efficient, accurate, comprehensive and more optimal than the previously used graph theory.     

Building Knowledge for Substation-Based Decision Support Using Rough Sets

This paper describes a new technique based on rough sets to extract decision rules from large volumes of data captured by protection, control, and monitoring intelligent electronic devices. The methodology correctly identifies faults from large datasets and could be used to assist operators in their decision-making processes. Building knowledge for a fault diagnostic system is a time-consuming and costly process. The quality of a knowledge base can sometimes be hampered by a large number of superfluous decision-making rules that can lead to an unnecessarily large knowledge base system and inefficient or even detrimental rule maintenance. The methodology proposed cannot only induce decision rules efficiently but can also reduce the size of the knowledge base without causing loss of useful information. Results can be used by an expert system to generate supervisory automation and to support operators, for example, during an emergency situation. This methodology involves the generation of human-machine interface alarms. These can then be used for diagnosis of the type and cause of a fault event to give suggestions for network restoration and post-emergency repair. A power systems computer aided design/electromagnetic transients including dc simulator has been used to investigate the effect of faults and switching actions on the protection and control equipment associated with a typical distribution network. The fundamental ideas of rough set theory are discussed, followed by a rule assessment method that is outlined using an illustrative example.     

基于负序功率方向比较与聚类算法的改进继电保护算法研究

分析了负序功率方向比较原理和聚类算法及其特点,提出了将两者有效结合的改进继电保护算法。利用系统广域信息量及实际系统拓扑结构划定相关母线和线路保护的关联域,建立关联保护的特征向量,给出系统状态信息矩阵,由矩阵的输出值进行故障判别。通过典型算例的故障定位及后备保护实现过程和结果,验证了该算法能够定位故障区域和故障元件。该算法应用于广域后备保护可提高信息冗余度,增强系统容错性。     

加强继电保护与紧急控制系统的研究提高互联电网安全防御能力

分析了我国电网西电东送、南北互供、全国联网实施过程中可能出现的问题：交、直流并列输电发生故障时，将对保护和控制装置的正确工作产生不利的影响；大功率、远距离输电断面输电能力的充分发挥问题；现有自动装置在动作值和动作时序的不协调，可能会造成网络结构的不稳定问题；稳定性控制系统难以防御小概率、大灾难事故     

110kV线路保护误动作分析及建议

通过对110kV并列运行双回线和双电源环网线路负荷侧保护在线路对侧母线出线故障时误动事例的分析,从改变运行接线方式、提高线路主保护配置及退出后备段保护3个方面提出解决措施,从而简化了负荷侧保护的整定配合及投退方案,提高了可靠性。结果表明:110kV线路配置光差保护,强化主保护功能,是电网多方式安全运行的必要保障。