多源信息融合技术在继电保护中的应用

随着电网规模的日益扩大,电力系统已成为一个高阶非线性和高度复杂性的系统,电力系统的故障信息也呈现多样性、随机性、复杂性和深度耦合性。多源信息融合技术的使用,能够有效解决现今继电保护领域中存在的复杂性故障分析难题。首先介绍了多源信息融合技术的原理和在继电保护领域的应用现状;然后从继电保护动作新判据、数据有效性甄别、智能化继电保护等方面,详细分析了多源信息融合技术在继电保护中的利用;最后对多源信息融合技术在继电保护中的未来应用领域进行了展望。     

继电保护中的信息技术

文章对继电保护系统在计算机、通信和数字信号处理技术的带动下走向信息化的发展过程进行了介绍,其中特别对小波变换在ＤＳＰ中的应用作了分析。最后,就有关继电保护信息的一些问题,包括信息共享对安全的影响进行了讨论。     

故障信息 小波变换与继电保护

故障信息是继电保护的基础。为研制新型继电保护,需要深入研究和充分利用各种故障信息。本文论述和比较电力系统故障后不同类型的故障信息,指出暂态故障信息和电力系统故障后断路器动作产生的二次优动信息是可利用的;小波变换是分析、提取和计算故障信息的重要手段;以暂态故障信息、断路器动作所产生的二次扰动信息的应用和小波变换为标志的新型行波保护、暂态保护和无通道保护是继电保护研究的重要方向。     

基于新疆继电保护故障信息系统的思考与深化应用

继电保护故障信息系统是依托于电力系统调度自动化而提出的,通过分析继电保护故障信息系统与电力系统调度的契合关系,分析了继电保护故障信息系统的组成结构及其工作原理,并明确了各个组成环节的功能。对于继电保护故障信息系统在电力系统中的深化应用方面,提出了数据的可视化处理,利用采集数据对新能源发电模型进行优化,利用故障分析结构进行故障反演。同时提出了在信息的综合分析环节当中增加一个信息筛选模块用以提高信息处理效率的系统优化方式。最后,对继电保护故障信息系统与能量管理系统的融合可能性、优越性以及结合的切入点进行了分析探讨。     

基于暂态量的继电保护研究

电力电子化设备的广泛应用导致电力系统故障暂态过程更加复杂、快速,对继电保护的“四性”提出了更高要求,基于暂态量的继电保护优势更加凸显。首先介绍了电力电子化电力系统的故障特性,详细分析了电力电子器件的快速调节特性与脆弱性以及对电力系统故障特性的影响。其次全面梳理了暂态量在线路保护中的应用,包括行波波头保护、单端暂态量保护等,并进一步分析了基于双端(多端)暂态量的保护新原理和新方法。最后给出了对暂态量保护研究的建议,通过合理利用故障全过程中丰富的暂态信息,实现与故障信息自适应匹配的高速暂态量保护,全面筑牢电网安全的“第一道防线”。     

继电保护与故障信息管理系统的应用及发展

对继电保护及故障信息管理系统的发展历史及研究现状进行了综述,介绍了继电保护及故障信息管理系统在广东电网公司中的应用,最后对继电保护及故障信息管理系统的发展进行了展望.     

故障行波信息理论在大型发电机故障检测中的应用研究——继电保护与故障定位

基于暂态故障行波的故障检测技术是未来电力系统不可或缺的技术手段和重要发展方向。基于故障行波信息对大型发电机进行继电保护和故障定位是其包括的重要内容,该文对该领域所涉及的理论研究做了综述性的分析。首先从大型发电机故障行波检测的应用空间探讨了对其故障行波研究的依据和可行性,接下来主要结合大型发电机定子的单相接地对故障行波传播的基本原理以及概念和特征做了简要介绍;随后对基于故障行波信息理论的大型发电机定子单相接地的继电保护和故障定位的原理与例证分析做了较深入的阐述;最后对行波保护技术在该领域进展做了总结和前瞻。     

自适应继电保护及其前景展望

自适应继电保护是计算机继电保护发展的一个重要方向。在讨论自适应继电保护的作 用、意义和分析其发展条件的基础上，指出了当前微机保护存在的问题，提出了自适应继电 保护发展的近期和远期目标，介绍了新研制成功的自适应电流保护原理。该保护装置能自动 适应电力系统运行方式的变化和故障状态，在线整定保护的定值，使其处于最佳状态。该装 置已投入试运行，运行情况良好。     

继电保护及故障信息系统在电力系统的应用

结合计算机网络技术、通信技术、远动技术的发展,一种新的信息系统应运而生.介绍了继电保护及故障信息系统的相关知识,技术特性及其在电力系统中的应用.     

广东电网继电保护及故障信息系统高级应用功能设计与实现

介绍了广东电网继电保护及故障信息系统高级应用的功能目标、设计方案和关键技术,以及在实际运行中的应用。应用该系统,可对实际发生的跳闸事故进行故障综合分析、故障信息发布等高级功能应用,也能对变电站继电保护装置和滤波设备的运行情况进行日常工作的管理,大大提高了系统事故的处理效率。     

A novel scheme for current-only directional overcurrent relay

Overcurrent relays are widely used as main protection in sub-transmission and distribution systems. In mesh and multi-source networks, application of directional relay is unavoidable. Traditional directional overcurrent relays use the reference voltage phasor as the polarizing quantity to estimate the direction of the fault. Traditional direction distinguishing scheme is unreliable in the case of close-in faults. In this paper, a novel algorithm for directional overcurrent relay is proposed. The new algorithm uses only current signals for determining the fault direction. It uses superimposed component of the current signal and does not require phasor estimation. This new algorithm uses pre-fault current signal as the polarizing quantity. The proposed method is tested on simple power system in different situations. The results show it leads to fast and reliable directional protection.     

Adaptive non-communication protection for power lines BO scheme3-The accelerated operation approach

This paper presents the accelerated operation scheme of the adaptive noncommunication protection technique for power lines with complex configurations, such as multi-end feeders and ring mains. In the scheme, the overcurrent directional relays are arranged in two operating modes, the fixed time operation and accelerated operation. The relays with faster operating time in the conventional time grading coordination remain unchanged. The new technique is employed to enable accelerated operation to be achieved for the relays which are in the positions for which slow operating time is set when using conventional time grading technique. For a fault occurring on the protected system, the relays of fixed time operation mode will operate at the preset time for the fault within its protected direction. The relays which are programmed to use accelerated operation mode will determine whether a fault is on the protected section or not by using the BO technique, that is to detect the circuit breaker operation by determining whether the line section is in a balanced operation condition or not. The relay makes accelerated tripping decisions for a fault on its protected section. Simulation studies of the responses to various system and fault conditions show that the scheme can significantly increase the speed of the relay responses in the protection of power line systems with complex configurations     

A novel neural network and backtracking based protection coordination scheme for distribution system with distributed generation

With the increased installation of renewable energy based distributed generations (DGs) in distribution systems, it brings about a change in the fault current level of the system and causes many problems in the current protection system. Hence, effective protection schemes are required to ensure safe and selective protection relay coordination in the power distribution system with DG units. In this paper, a novel adaptive protection scheme is proposed by integrating fault location with protection relay coordination strategies. An automated fault location method is developed using a two stage radial basis function neural network (RBFNN) in which the first RBFNN determines the fault distance from each source while the second RBFNN identifies the exact faulty line. After identifying the exact faulty line, then protection relay coordination is implemented. A new protection coordination strategy using the backtracking algorithm is proposed in which it considers the main protection algorithm to coordinate the operating states of relays so as to isolate the faulty line. Then a backup protection algorithm is considered to complete the protection coordination scheme for isolating the malfunction relays of the main protection system. Several case studies have been used to validate the accuracy of the proposed adaptive protection schemes. The results illustrate that the adaptive protection scheme is able to accurately identify faulty line and coordinate the relays in a power distribution system with DG units. The developed adaptive protection scheme is useful for assisting power engineers in performing service restoration quickly so as to decrease the total down time during faults.     

基于用户自定义特征的反时限有源配网保护方案

由于分布式电源输出功率的随机性与波动性,当分布式电源大量接入配电网后,传统的反时限过电流保护方案很难满足配电网保护选择性和速动性的要求。为此,文章通过研究数字反时限过流保护继电器,提出一种基于用户自定义特征的反时限过电流保护方案。保护方案将反时限继电器的特性常数(A)和反时限的类型常数(B)同继电器的时间整定系数、启动电流共同作为待优化的连续变量,并以最小故障电流时所有保护动作时间之和最小为目标函数,利用内点法求解保护的最优配置。方案保证了线路出口处故障时保护能快速动作,满足了配电网保护选择性和速动性的要求。最后,通过仿真分析,对保护方案进行了验证。     

Data-mining model based adaptive protection scheme to enhance distance relay performance during power swing

The paper presents a data-mining model based adaptive protection scheme enhancing distance relay performance during power swing for both compensated and uncompensated power transmission networks. In the power transmission network, the distance relays are sensitive to certain system event such as power swings, which drive the apparent impedance trajectories into the protection zones of the distance relay (zone-3) causing mal-operation of the distance relay, leading to subsequent blackouts. Further, three-phase balanced symmetrical fault detection during power swing is one of the serious concerns for the distance relay operation. This paper proposed a new adaptive protection scheme method based on data-mining models such as DT (decision tree) and RF (random forests) for providing supervisory control to the operation of the conventional distance relays. The proposed scheme is able to distinguish power swings and faults during power swing including fault zone identification for series compensated power transmission network during stress condition like power swing. The proposed scheme has been validated on a 39-bus New England system which is developed on Dig-Silent power factory commercial software (PF4C) platform and the performance indicate that the proposed scheme can reliably enhance the distance relay operation during power swing.     

Protection relay system using information network for distribution system with DGs

We propose a new protection scheme for selective and quick disconnection of a fault area in a distribution system, which can be flexibly adopted for a large‐scale introduction of distributed generators (DGs). When a fault occurs, relays provide a binary state signal which is activated if, for instance, the current at the corresponding relay location exceeds a certain value. Although each relay cannot locate the fault point with only its own signal, it can locate the fault by utilizing signals from other relays together with its own signal. Because only a binary state signal is transmitted instead of the actual physical variable such as the magnitude of the fault current, the network traffic is much less than when a conventional protection scheme for a transmission system using an information system is applied to a distribution system. The following are the main results of a simulation on our proposed protection scheme: (1) the proposed protection scheme can successfully disconnect only a fault feeder when the relays use signals provided from the sending end of the fault feeder and all other DGs on the same feeder, (2) in the case of a fault on a DG connected feeder, the DG can be disconnected within 0.06 s. © 2006 Wiley Periodicals, Inc. Electr Eng Jpn, 155(4): 30–35, 2006; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/eej.20232     

Communication-based Adaptive Protection for Distribution Systems Penetrated with Distributed Generators

In this article, a communication-based adaptive over-current protection scheme for distribution systems penetrated with distributed generators is proposed. A communication network between the over-current relays, the distributed generators, and the utility grid is employed to automatically update the settings of the protective relays. Moreover, the communication reliability is increased through the addition of a backup communication system. The proposed scheme has the advantage of operating during grid-connected and islanding modes of operation. The scheme employs two simultaneous algorithms. The first algorithm works when the system configuration is changed due to the connection/disconnection of a distributed generator or the utility grid. The second algorithm efficiently uses the exchanged information between the relays to identify the faulted section and hence speeds up fault clearance. The proposed scheme is tested for difierent fault conditions as well as for different system configurations. The results demonstrated that relay operating times, including the communication delay, are greatly reduced when the faulted section is identified and relay settings are adjusted accordingly. In addition, a negligible time delay was experienced when the backup communication network was put in service.     

Adaptive non-communication protection for power lines BO scheme1-The delayed operation approach

This paper proposes a new technique in power line protection, the "adaptive non-communication protection". In this technique, protection relays make operate or restraint decisions, adapting to system and fault conditions, without the need for communication links. Operation without communication links to signal the remote end relay is achieved by the detection and identification of the operation of the circuit breaker at the remote end of the protected line section. An algorithm based on symmetric components is proposed to detect and identify the balance condition of the power system during the fault. The paper is focused on one of the three protection schemes based on the new technique, the delayed operation scheme. Simulation studies carried out for various power systems and fault conditions have demonstrated its feasibility     

An accurate technique for locating faults by distance relays

This paper presents a new protection scheme for improving the performance of the distance protective relays in transmission systems. The determination of fault zone by the proposed scheme is based on data sheared locally with other distance relays at the same station, in addition to a command from the distance relay on the other end of the protected line. Based on analyzing this information the relay decides the correct fault zone. With the proposed scheme, the first zone in the distance relay covers the full length of the protected line while the second zone covers the full length of any line following the protected line irrespective of its length, etc. The scheme is examined against wide range of setting problems of a real part of a HV network with real relay settings. It succeeds in solving distance relay setting problems, e.g. the problem of a long line following a short line or vice versa, low in-feed, open CB at one end and high impedance faults.     

New coordination approach to minimize the number of re-adjusted relays when adding DGs in interconnected power systems with a minimum value of fault current limiter

The presence of DGs in power networks tends to negatively affect relays coordination. Adding fault current limiters FCLs is one of the possible solutions to mitigate negative impacts of DGs addition on protection systems. Traditional schemes have estimated the minimum value of FCL to restore relays coordination when adding DGs without resetting of any relays. That minimum value of FCL in such case is called a critical value, where below this value the relays coordination will be lost.Nowadays, designing FCL to simultaneously achieve two conflicted objectives of good performance and low cost is considered a great challenge. The paper introduces a new scheme to determine to what extent we could decrease FCL impedance value below its critical value with re-adjusting the original settings of only one adaptive relay to get relays coordination. Decreasing FCL value below its critical value will reduce the cost especially for superconductivity FCL. The proposed scheme can determine the location of that selected relay to be an adaptive one and estimate its re-adjusted new settings to be applied when DGs are added while inserting the reduced value of FCL.Actually the proposed scheme can be applied for any networks irrespective of the number of added DGs and their capacities; while having an adaptive relay is the only requirement to implement it.The proposed approach is implemented and effectively tested on the large well-known interconnected IEEE-39 bus test system with 84 relays. Its results are compared with other approaches where, no re-adjusted relays settings are applied. A noteworthy advantage of the proposed scheme is the ability to implement a reduced FCL value than the critical value, by adjusting only one relay settings in the whole network. The proposed scheme may also be extended to re-adjust settings of more than one relay and get further reduced value of FCL. Furthermore, it is also shown that a more optimum value of the total operating time of all primary relays for near end faults is achieved when applying the proposed method rather than other traditional schemes.