發(fā)布時間：2018-02-20 14:58

  本文關(guān)鍵詞： 薄弱線路 潮流熵 電網(wǎng)風(fēng)險 層次分析法 熵權(quán)法　出處：《長沙理工大學(xué)》2014年碩士論文　論文類型：學(xué)位論文

【摘要】：近幾年來,世界范圍內(nèi)發(fā)生了很多起大規(guī)模停電事故,給國民生產(chǎn)以及人民日常生活帶來了不可估量的損失與影響。由于傳統(tǒng)安全的電力系統(tǒng)可靠性分析方法已經(jīng)無法有效地保證電網(wǎng)的安全運行,研究人員開始提出電網(wǎng)線路薄弱性的概念,試圖在事故發(fā)生前分析出電網(wǎng)的某些薄弱線路,并對薄弱線路加以修護(hù)或者修繕,來預(yù)防大規(guī)模停電事故。因此,本文試圖通過研究如何尋找電網(wǎng)薄弱環(huán)節(jié)與分析薄弱環(huán)節(jié)的具體成因,為降低電網(wǎng)風(fēng)險性,提供可靠的保障。論文介紹了國內(nèi)外數(shù)起大規(guī)模停電事故與發(fā)生原因。在此基礎(chǔ)上,梳理了國內(nèi)外學(xué)者針對電網(wǎng)故障以及風(fēng)險評估的研究方法,并歸納各方法的優(yōu)缺點。同時總結(jié)了我國電網(wǎng)可靠性現(xiàn)狀。為了篩選出電網(wǎng)的薄弱線路,論文嘗試引入潮流熵的概念對電網(wǎng)薄弱線路進(jìn)行辨識。本文從熵原理出發(fā),結(jié)合斷開線路后潮流轉(zhuǎn)移的分布特性,定義了潮流熵,提出了基于潮流熵理論的薄弱線路計算方法。針對電網(wǎng)實際運行特點,建立了基于潮流熵的支路后果薄弱性計算指標(biāo)與基于潮流熵的支路抗沖擊薄弱性計算指標(biāo)。它兼顧線路斷開后果與線路本身堅強(qiáng)程度兩方面來考慮線路的薄弱程度。以IEEE39節(jié)點系統(tǒng)為例,運用潮流熵法對電網(wǎng)線路進(jìn)行薄弱性計算,篩選出了薄弱線路,其結(jié)果與其他文獻(xiàn)數(shù)據(jù)對比一致,驗證了運用潮流熵法辨識線路薄弱度的有效性。為了分析線路的薄弱原因,論文在一定原則上建立了風(fēng)險評價體系,包括考慮全網(wǎng)的負(fù)荷狀況、電壓水平、靜態(tài)安全性水平三個方面的狀況。論文運用了層次分析法與熵權(quán)法兩種賦權(quán)方法來確定風(fēng)險評價體系中各項指標(biāo)的權(quán)重。層次分析法是屬于主觀類賦權(quán)法,相對重要性是指標(biāo)與指標(biāo)之間相互比較得出的。熵權(quán)法屬于依據(jù)客觀數(shù)據(jù)直接反映到熵值的大小,能夠修正層次分析法過分依賴決策者主觀判斷的缺陷。因此提出了熵修正的層次分析法。在確定指標(biāo)權(quán)重后,針對篩選出的薄弱線路進(jìn)行比較分析,獲得薄弱線路的薄弱原因。在IEEE39節(jié)點系統(tǒng)上,運用熵修正的層次分析法確定各項指標(biāo)權(quán)重。根據(jù)潮流熵法篩選的薄弱線路,運用模糊層次分析法對薄弱線路進(jìn)行兩相比較,分析薄弱線路對各項指標(biāo)的影響,為解決和修繕薄弱線路提供先導(dǎo)依據(jù)。
[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.
【學(xué)位授予單位】：長沙理工大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2014
【分類號】：TM727
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本文編號：1519248