【摘要】：覆冰威脅電網(wǎng)的安全運(yùn)行,影響電力的安全輸送,擾亂人民的日常生活,我國(guó)是世界上架空線路遭受冰災(zāi)較嚴(yán)重的國(guó)家之一,覆冰事故頻發(fā)給電力系統(tǒng)帶來(lái)巨大的經(jīng)濟(jì)損失。隨著西電東送、超高壓輸電等建設(shè)的進(jìn)行,我國(guó)電網(wǎng)覆蓋面積越來(lái)越大,經(jīng)過(guò)的惡劣地理環(huán)境越來(lái)越多,越來(lái)越容易受到覆冰事故的影響,加之全球氣候愈加惡劣,覆冰帶來(lái)的威脅越來(lái)越嚴(yán)峻。解決架空輸電線路覆冰問(wèn)題,具有重要的工程應(yīng)用意義。本文對(duì)線路覆冰的影響因素、形成條件,飛機(jī)、鐵路接觸網(wǎng)、輸電線路覆冰的危害,輸電線路覆冰的特點(diǎn),覆冰在線監(jiān)測(cè)和除冰方法進(jìn)行了介紹,概述了國(guó)內(nèi)外防冰技術(shù)研究進(jìn)展,總結(jié)了現(xiàn)有研究的不足,介紹了國(guó)內(nèi)外專家學(xué)者提出的防冰臨界電流理論模型,簡(jiǎn)述了計(jì)算臨界電流時(shí)需要用到的幾種較為經(jīng)典的對(duì)流換熱準(zhǔn)則公式與實(shí)驗(yàn)關(guān)聯(lián)式,由此提出了本文的主要研究?jī)?nèi)容。本文根據(jù)量綱分析建模理論,首次運(yùn)用量綱分析法,在對(duì)影響防冰臨界電流的主要因素進(jìn)行全面分析的基礎(chǔ)上,根據(jù)Π定理,得出了與之相關(guān)的一系列無(wú)量綱量(5個(gè)),這些無(wú)量綱量是氣象參數(shù)(氣溫、風(fēng)速、空氣中液態(tài)水含量、液滴直徑)與導(dǎo)線參數(shù)等的組合,經(jīng)過(guò)進(jìn)一步推導(dǎo)得出了與臨界電流有關(guān)的無(wú)量綱量,分析了各無(wú)量綱量的物理意義。介紹了冰風(fēng)洞實(shí)驗(yàn),并運(yùn)用導(dǎo)線覆冰臨界狀態(tài)熱平衡方程,導(dǎo)出了對(duì)流換熱系數(shù)的計(jì)算模型,利用冰風(fēng)洞實(shí)驗(yàn)數(shù)據(jù)得出一定條件下的對(duì)流換熱系數(shù),使用數(shù)據(jù)分析軟件擬合得到努謝爾數(shù)與對(duì)應(yīng)的雷諾數(shù)的關(guān)聯(lián)式,分析了與其他較經(jīng)典的經(jīng)驗(yàn)公式的區(qū)別與聯(lián)系,分析了實(shí)驗(yàn)誤差。在此基礎(chǔ)上,利用實(shí)驗(yàn)所得無(wú)量綱數(shù)據(jù)分析了無(wú)量綱量的變化規(guī)律,根據(jù)非線性回歸分析方法,分別運(yùn)用主成分分析法、多項(xiàng)式擬合法和指數(shù)乘積擬合法對(duì)得到的無(wú)量綱量進(jìn)行了擬合,得到了計(jì)算臨界電流的理論模型,并計(jì)算了相對(duì)誤差和平均相對(duì)誤差,與熱平衡模型計(jì)算結(jié)果進(jìn)行了比較,驗(yàn)證了實(shí)驗(yàn)的準(zhǔn)確性,結(jié)果表明,運(yùn)用量綱分析建模結(jié)合指數(shù)乘積擬合法進(jìn)行防冰臨界電流研究是可行的。本文提出的防冰臨界電流量綱分析建模方法,在國(guó)內(nèi)首次使用,得到的防冰臨界電流準(zhǔn)則公式為電網(wǎng)進(jìn)行臨界電流防冰提供了理論支撐,具有一定的工程應(yīng)用意義。
[Abstract]:Icing threatens the safe operation of power grid, affects the safe transmission of electric power, and disturbs the daily life of people. China is one of the countries with serious ice disasters on overhead lines in the world, and the frequent occurrence of icing accidents brings huge economic losses to the power system. With the construction of power transmission from west to east and ultra-high voltage transmission, the area of power grid in our country is more and more large, the bad geographical environment is more and more, more and more vulnerable to the influence of icing accidents, and the global climate is becoming more and more bad. The threat of icing is becoming more and more serious. It is of great significance to solve the icing problem of overhead transmission lines. In this paper, the influence factors, forming conditions, aircraft, railway catenary, transmission line ice, the characteristics of transmission line icing, the on-line monitoring and deicing methods are introduced. This paper summarizes the research progress of anti-ice technology at home and abroad, summarizes the shortcomings of existing research, and introduces the theoretical model of anti-ice critical current put forward by experts and scholars at home and abroad. In this paper, several classical formulas of convection heat transfer criterion used in calculating critical current and their experimental correlations are briefly described, and the main research contents of this paper are put forward. In this paper, based on dimensional analysis modeling theory, dimensionality analysis method is used for the first time. Based on the comprehensive analysis of the main factors affecting the critical current of anti-ice, and according to the 蟺 theorem, A series of dimensionless quantities (5) are obtained, which are the combination of meteorological parameters (temperature, wind speed, liquid water content in air, droplet diameter) and traverse parameters, etc. The dimensionless quantities related to the critical current are derived and the physical meaning of the dimensionless quantities is analyzed. The ice wind tunnel experiment is introduced, and the calculation model of convective heat transfer coefficient is derived by using the heat balance equation of the critical state of conductor icing. The convection heat transfer coefficient under certain conditions is obtained by using the ice wind tunnel experimental data. The correlation between the Nuschel number and the corresponding Reynolds number is obtained by using the data analysis software. The difference and relation between the Nuschel number and the other classical empirical formulas are analyzed, and the experimental errors are analyzed. On this basis, using the dimensionless data obtained from the experiment to analyze the change of dimensionless quantity, according to the method of nonlinear regression analysis, the principal component analysis method is used respectively. The polynomial fitting method and exponential product fitting method are used to fit the dimensionless quantities, and the theoretical model for calculating critical current is obtained. The relative error and average relative error are calculated, and the results are compared with those of the thermal equilibrium model. The accuracy of the experiment is verified. The results show that it is feasible to use dimension analysis modeling and exponential product fitting to study the critical current of anti-ice. For the first time in our country, the critical current dimensionality analysis method proposed in this paper is used for the first time in China. The formula of anti-ice critical current criterion has provided the theoretical support for the critical current anti-ice of the power network, and has certain engineering application significance.
【學(xué)位授予單位】：長(zhǎng)沙理工大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2014
【分類號(hào)】：TM752

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相關(guān)期刊論文 前1條

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本文編號(hào)：2243786