基于熵修正的层次分析法的电网薄弱线路的评判与分析

发布时间：2018-02-20 14:58

  本文关键词： 薄弱线路 潮流熵 电网风险 层次分析法 熵权法　出处：《长沙理工大学》2014年硕士论文　论文类型：学位论文

【摘要】：近几年来,世界范围内发生了很多起大规模停电事故,给国民生产以及人民日常生活带来了不可估量的损失与影响。由于传统安全的电力系统可靠性分析方法已经无法有效地保证电网的安全运行,研究人员开始提出电网线路薄弱性的概念,试图在事故发生前分析出电网的某些薄弱线路,并对薄弱线路加以修护或者修缮,来预防大规模停电事故。因此,本文试图通过研究如何寻找电网薄弱环节与分析薄弱环节的具体成因,为降低电网风险性,提供可靠的保障。论文介绍了国内外数起大规模停电事故与发生原因。在此基础上,梳理了国内外学者针对电网故障以及风险评估的研究方法,并归纳各方法的优缺点。同时总结了我国电网可靠性现状。为了筛选出电网的薄弱线路,论文尝试引入潮流熵的概念对电网薄弱线路进行辨识。本文从熵原理出发,结合断开线路后潮流转移的分布特性,定义了潮流熵,提出了基于潮流熵理论的薄弱线路计算方法。针对电网实际运行特点,建立了基于潮流熵的支路后果薄弱性计算指标与基于潮流熵的支路抗冲击薄弱性计算指标。它兼顾线路断开后果与线路本身坚强程度两方面来考虑线路的薄弱程度。以IEEE39节点系统为例,运用潮流熵法对电网线路进行薄弱性计算,筛选出了薄弱线路,其结果与其他文献数据对比一致,验证了运用潮流熵法辨识线路薄弱度的有效性。为了分析线路的薄弱原因,论文在一定原则上建立了风险评价体系,包括考虑全网的负荷状况、电压水平、静态安全性水平三个方面的状况。论文运用了层次分析法与熵权法两种赋权方法来确定风险评价体系中各项指标的权重。层次分析法是属于主观类赋权法,相对重要性是指标与指标之间相互比较得出的。熵权法属于依据客观数据直接反映到熵值的大小,能够修正层次分析法过分依赖决策者主观判断的缺陷。因此提出了熵修正的层次分析法。在确定指标权重后,针对筛选出的薄弱线路进行比较分析,获得薄弱线路的薄弱原因。在IEEE39节点系统上,运用熵修正的层次分析法确定各项指标权重。根据潮流熵法筛选的薄弱线路,运用模糊层次分析法对薄弱线路进行两相比较,分析薄弱线路对各项指标的影响,为解决和修缮薄弱线路提供先导依据。
[Abstract]:In recent years, there have been many large-scale blackouts around the world. It has brought incalculable loss and influence to the national production and people's daily life. Because the traditional reliability analysis method of electric power system can not effectively guarantee the safe operation of power grid, Researchers began to put forward the concept of power line weakness, trying to analyze some of the weak lines of the power network before the accident, and repair or repair the weak lines to prevent large-scale power outages. In this paper, we try to find out the weak links of power grid and analyze the specific causes of the weak links, in order to reduce the risk of power grid and provide reliable protection. This paper introduces several large-scale power outage accidents and their causes at home and abroad. This paper summarizes the research methods of fault and risk assessment of power network, summarizes the advantages and disadvantages of each method, and summarizes the current situation of power network reliability in China. In this paper, the concept of power flow entropy is introduced to identify the weak lines of the power network. Based on the entropy principle and the distribution characteristics of the power flow transfer after the disconnected line, the power flow entropy is defined in this paper. Based on the theory of power flow entropy, a method for calculating weak lines is proposed. The calculation index of branch consequence weakness based on power flow entropy and the calculation index of branch impact vulnerability based on power flow entropy are established. The weak path of the line is considered from two aspects: the consequence of line disconnection and the strength of the line itself. Take the IEEE39 node system as an example, Power flow entropy method is used to calculate the weakness of power transmission lines, and the weak lines are screened out. The results are consistent with other literature data, and verify the effectiveness of using the power flow entropy method to identify the weak degree of transmission lines. In this paper, a risk assessment system is established in principle, including considering the load condition and voltage level of the whole network. The paper uses two kinds of weighting methods, AHP and entropy weight method, to determine the weight of each index in the risk evaluation system. Relative importance is derived from the comparison between indicators. Entropy weight method is based on objective data directly reflected to the magnitude of entropy. It can correct the defects of AHP, which relies too much on the subjective judgment of decision makers. Therefore, an entropy modified AHP is put forward. After determining the index weight, the weak lines selected are compared and analyzed. The weak causes of weak lines are obtained. In the IEEE39 node system, the weight of each index is determined by entropy modified analytic hierarchy process (AHP). According to the weak lines screened by the power flow entropy method, the weak lines are compared with each other by fuzzy analytic hierarchy process (FAHP). The influence of weak line on each index is analyzed to provide the guide for solving and repairing weak line.
【学位授予单位】：长沙理工大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TM727
，

本文编号：1519248