【作者】 丛伟；

【导师】 潘贞存；

【作者基本信息】 山东大学 ， 电力系统及其自动化， 2005， 博士

【摘要】 我国“西电东送、南北互供、全国互联”发展战略的实施将带来前所未有的大规模、远距离输电,届时将形成北、中、南三个跨区大型互联电网。大型互联电网的发展给继电保护和稳定控制系统提出了更高的要求,不仅要保证电气设备安全的运行,还要保证电网受到扰动后能安全稳定的运行,在发生恶劣事故的情况下不发生连锁跳闸和系统崩溃。高速、可靠的继电保护措施,准确、及时的安全控制和紧急控制措施以及大型互联电网的安全稳定防御措施是保证电网安全稳定运行的重要保障。 我国自上个世纪80年代以来坚持实施“三道防线”的稳定控制措施,取得了良好的运行效果,积累了确保电网安全稳定运行的宝贵经验。随着电网规模的扩大,互联趋势的加强,基于本地量的保护和自动控制判据不能全面的反映系统的运行状态,可能出现保护和安全自动装置动作不恰当的情况,“三道防线”中的每道防线基本处于“各自为政”的状态,相互之间缺乏必要的配合与协调,有时会导致事故范围扩大。本文提出了满足“三道防线”要求的广域保护系统,从完成功能的角度上对广域保护系统进行了定义,讨论了系统的总体结构、功能配置和通信系统设计等若干关键问题。满足“三道防线”要求的广域保护系统将传统的“三道防线”功能与新兴的广域保护系统概念结合起来,以电力系统广域信息为依托,能动态的、较客观的反映系统运行状态。同时把“三道防线”功能集中到一个系统内完成,建立起各道防线之间的联系,把原本独立、离散的控制措施变为协调、连续的措施,在保证互联电网不发生连锁跳闸和崩溃的目标前提下实现保护和控制策略的优化,即尽量缩小故障影响区域,减少停电时间。 提出了基于纵联比较原理的广域继电保护算法,该算法通过比较故障相邻区域内各IED对故障方向的判断结果进行准确的故障判别,根据故障位置执行相应的继电保护策略。本文研究的广域继电保护系统采用分布式结构,以IED为中心进行故障判别计算并执行跳闸操作。故障发生后,故障相邻区域内每个IED都能明确故障的具体位置。IED不仅能对区内故障提供快速的主保护功能,还能提供快速的后备保护功能,后备保护的选择性依靠广域信息来保证,动作定值的整定更多还原

【Abstract】 With the implementation of development stratagem about "transmit electricity from west to east, north supports power supply to south and vice versa, connect power grids nationwide", three huge interconnected power girds in north, middle and south of China will come into being. The situation of large scale power girds and long transmission distances are new problems brought forward for relaying protection system and stability control system, which must operate more efficiently and reliably than ever before to meet high requirements. Effective relaying protection and stability control system should not only protect electrical devices from being damaged by fault, but also protect power from collapse by severe disturbances. They are the most important protective measures for large scale power grids to operate stably and reliably.Stability control measures known as famous "Three Defensive Lines" in China has been brought into effect sine 1980’s and achieved excellent operation results. Several large scale blackouts have been avoided and plenty of experiences to insure power grids operate stably and reliably have been accumulated. With the enlargement and interconnection of power grids, traditional "Three Defensive Lines" is difficult to meet higher requirements than before. Because traditional "Three Defensive Lines" are formed by several unaided relaying protection and stability control measures, which operate based on local electrical quantities and without necessary cooperation each other. In sometimes, relaying protection or stability control measures operate correctly, but power grids will lose its stability. A wide area protection system to meet the requirements of "Three Defensive Lines" is proposed in this thesis. The definition of this wide area protection system is proposed from the point of view in functions it should possess. Some critical issues of system structure, functions configuration, communication system and so on about this wide area protection are discussed. The wide area protection system proposed in this thesis combines traditional "Three Defensive Lines" with emerging conception of wide area protection system, operatesbased on wide area information, and reflects power system operation status dynamically and factually. A wide area protection system to meet the requirements of "Three Defensive Lines" integrates functions of traditional "Three Defensive Lines" into one system to achieve cooperation and harmony among every defensive line. The control goal of this wide area protection system is to prevent power system from being collapsed when suffering from sever disturbances with optimized protection and control measures, that is reduce disturbance affected area and blackout times.A wide area relaying protection algorithm based on longitudinal comparison principle is proposed. By executing this algorithm based on fault direction information of wide area IEDs near fault, the fault site can be easily located and effective tripping strategies can be implemented. Wide area relaying protection system adopts distributed structure, fault locations algorithm is implemented in IED. After fault occurrence, every IED near fault site knows where the fault locates correctly. IED can provide not only fast primary relaying protection functions, but also fast backup protection functions. The selectivity of wide area relaying protection system is achieved based on wide area fault information instead of different operation time delay. So it is convenient to set setting values and operation time delay for relaying protection functions.A wide area relaying protection algorithm based on current differential principle is proposed. The current differential theory in wide area relaying protection system is the same with ordinary one, the difference is that the former utilizes wide area current and can provide current differential protection for wide area. Because current differential theory has better performances than the other theories, wide area current differential relaying protection system can provide protection functions with excellent performances. In order to lighten the pressure of communication caused by transmitting large quantities of analog sampling data as well as guarantee the rapidness and reliability of wide area relaying protection system, "Searching Method" is proposed to determine protection zone and associated area for IED. Protection zone and associated area can change according to topology of power grids. When faultoccurs, 1 ED exchanges fault current only within its protection zone with its assoeiated IEDs.The concept of "N-l" in relaying protection system is proposed by referencing that concept in power system analysis field. "N-l" in relaying protection system mainly contains protection miss operation, maloperation, circuit breaker failure and communication system failure, which will damage the performance of relaying protection system. The strategies against relaying protection system "N-l" status are discussed. Some special problems exist in relaying protection systems are analyzed and resolving measures are proposed based on wide area information. The performances of these two wide area relaying protection systems are compared.GSE (Genetic Substation Event) and SAV (Sampling Analog Values) models in IEC61850 are studied. They are proposed to apply in transmitting fault direction information in wide area longitudinal comparison relaying piolection system, and fault current information in wide area current differential relaying protection system.Ethernet is proposed to accomplish communication functions in substation LAN. In order to investigate the performance of Ethernet, special communication system simulation software —OPNET (Optimum Network Performance) is utilized to .simulate some critical parameters such as Ethernet delay, data diagram dropped, network traffic under typical communication environment. Simulation results show that Ethernet is sufficient to act as communication system in wide area protection system.Project supported by National Natural Science Foundation of China (50477041) and Xuji Electric Power Special Foundation.更多还原