【作者】 许婧；

【导师】 白晓民；

【作者基本信息】 中国电力科学研究院 ， 电力系统及其自动化， 2011， 博士

【摘要】 随着电网互联的加强,在提高了系统经济性的同时,电网的整体安全性问题日益突出。局部电网某些故障的影响有可能波及附近的区域电网,并诱发连锁过程,导致严重的事故后果。传统的分析方法在深入分析电网连锁故障方面显露出一定的局限性,因此,有必要开展电力系统连锁故障过程的故障诊断以及防控方法的研究。本文在深入分析电力系统连锁故障发生、发展的演化过程的基础之上,结合电力系统的实际需要,开展了考虑保护隐藏故障的系统N-k故障分析,对连锁故障过程中的故障诊断、以及连锁故障时系统防控方法等问题进行了研究,主要工作如下：1.针对连锁故障中存在的过程复杂,影响因素繁多等分析难点,在深入分析连锁故障的演化过程特点的基础上,提出应将连锁故障的分析和控制的重点放在故障的发展阶段,并进一步将其分为故障初始发展、缓慢相继故障和快速连锁故障三个阶段。针对各阶段的特点,给出了相应的分析和防控的重点。2.针对几类典型的、具有不同原理的保护,分析了其由于保护元件功能缺陷或定值不合理造成的各种隐藏故障模式；在此基础上,提出了一类基于元件功能缺陷、具有共性特征的保护隐藏故障的分析思路,从本质上分析了由于隐藏故障导致保护误动的原因。3.提出了考虑保护隐藏故障的N-k故障分析评估算法,分析了保护隐藏故障对系统可靠性的影响。通过随机初始故障触发保护的隐藏故障导致线路误动,将保护的隐藏故障反映到多重预想事故的选择和故障组合上。应用该方法对系统进行N-k预想事故筛选,可以辨识系统的脆弱线路和关键保护,为系统有重点地加强监控提出建议。4.利用连锁故障过程中故障事件的特点,采用复杂事件处理技术,提出了侧重分析系统故障动态发展趋势的电网连锁故障诊断分析方法。建立了分层的事件处理和关联分析模型,通过相继故障事件之间存在的时间、拓扑和电气的因果及聚合关系,对相继故障事件进行关联和聚合,对连锁故障进行诊断。5.结合当前的电网分层分区运行体系,借鉴现有的系统稳定运行控制经验,构建了具有工程实践意义的分层分区基于MAS的广域协同预控制系统框架。引入计及发电机响应的断面潮流准稳态分析方法,利用离线断面功率传输极限,从全局的角度预先控制重要断面的潮流水平,防止局域电网故障的发展扩大,保证全网的安全稳定运行。更多还原

【Abstract】 With the development of power grid interconnection, the overall grid security issues become increasingly prominent as well as the improvement of the operational economy. Some failure of the local power grid may spread to nearby regional power grid, which may induce cascading process and lead to serious consequences. The traditional methods have some limitation in aspects of analyzing cascading failures. Therefore, it is necessary to carry out the research of diagnosis, prevention and control approaches for cascading failures in power system.Based on in-depth analysis of the evolution process of cascading failure, involving its occurrence and development, the research of N-k contingency analysis considering of protection hidden failures, fault diagnosis and prevention and control methods for cascading failure have been carried out. The main efforts are listed as follows:1. On the basis of in-depth analysis of characteristic of cascading failures evolvement process, it is indicated that the emphasis of analysis and control should be put on the development stage of cascading failures, which is divided into initial phase, slow and fast cascade phase. The corresponding analysis and control focus are presented according to different characteristics of three phases.2. Kinds of hidden failure (HF) modes caused by protection element functionality defect or improper settings have been listed and analyzed for several types of typical protections with different operational principles. Based on that, one analytical mode of protection HF caused by protection element functionality defect with common features is presented. From which, the reason for protection malfunction caused by hidden failure has been revealed essentially.3. N-k contingency analysis method taking protection hidden failure into consideration is proposed, which can evaluate the effect of protection hidden failure on the system reliability. There exists a linkage between a first contingency (random initial fault) and a possible second outage due to hidden failures in protection systems, which could be exposed by multiple contingencies options and failure combinations. The method for culling the list of possible higher order (N-K) contingencies could be used to recognize vulnerable lines and key protections in the system, which is helpful to improve the system monitoring with priority.4. A diagnosis and analysis method for cascading failure based on complex event processing technology (CEP) is proposed by use of characteristics of fault events during cascading process, which focus on dynamic development trend of failures in power system. A hierarchy model for complex event processing and correlation analysis is developed. Successive failure events are correlated by analyzing the temporal, spatial and electrical correlation between them, which can offer tendency analysis of failure development and confirm the starting of cascading failure.5. Taken present hierarchical and network partition structure into consideration, drawn on existing system stable operational control experience, a framework of wide-area coordinated pre-control based on multi-agent system (MAS) is built, which is of engineering practice value. With the introduction of interfaces power flow algorithm under quasi-steady-state taken into account of generator response, power flow level of key transmission section can be controlled in advance from the system point of view by means of power transfer limit of cross-section calculated offline, which can prevent the development of fault occurred in local network, and thus ensure security and stability operation of the whole power grid.更多还原