空氣濕度對直流電暈放電影響的研究
發(fā)布時間:2018-02-16 11:49
本文關(guān)鍵詞: 直流電暈放電 相對濕度 放電參數(shù) 電流密度 電暈起始場強 電暈效應 出處:《山東大學》2014年博士論文 論文類型:學位論文
【摘要】:實施我國西電東送的能源戰(zhàn)略,國家已經(jīng)投運了多條不同等級的高壓和特高壓直流輸電線路。特高壓直流輸電需要考慮輸電過程中電暈放電的產(chǎn)生。電暈放電不但增加線路的功率損耗,還會導致無線電干擾、可聽噪聲等一系列的環(huán)境問題。隨著經(jīng)濟的不斷發(fā)展,環(huán)境問題越來越受到人們的關(guān)注,并受到環(huán)保法規(guī)的嚴格制約。這就使得電暈放電成為決定直流輸電線路結(jié)構(gòu),影響建設(shè)費用的重要因素。我國特高壓直流輸電線路的輸送距離遠,工程沿線地形、地貌與氣象條件復雜,不可避免地需要經(jīng)過高濕度地區(qū)。因此,研究空氣濕度對直流電暈放電的影響具有重要的理論意義和實際意義。 本文針對空氣濕度對導體電暈放電的影響進行了深入研究。系統(tǒng)地計算分析了空氣濕度對支配電暈放電性質(zhì)的參數(shù),如電離系數(shù)、附著系數(shù)、光子吸收系數(shù)、電子和離子漂移系數(shù)以及電離層半徑等的影響;趯w電暈起始場強的分解、對考慮濕度的電暈起始場強構(gòu)成的理論分析和電暈起始場強的模擬計算,研究了Peek公式的修正。結(jié)合本文給出的修正的Peek公式,系統(tǒng)地計算分析了濕度對電暈效應的影響。本論文主要包含以下方面的內(nèi)容和結(jié)果: (1)介紹了環(huán)境空氣的組成和特性以及電暈放電中的電離、附著等物理過程。在此基礎(chǔ)上,描述了正、負極性導體電暈放電機理,描述了正、負極性導體電離層中電荷數(shù)量密度分布的一維數(shù)學模型。 (2)電暈放電的性質(zhì)與多個參數(shù)相關(guān),即電離系數(shù)、附著系數(shù)、光子吸收系數(shù)、電子漂移速度和正離子漂移速度等。因此,空氣濕度對電暈放電性質(zhì)的影響將通過對這些參數(shù)的影響來產(chǎn)生。基于對濕空氣下的各放電參數(shù)相應于干空氣和水蒸氣的分解,系統(tǒng)地計算分析了空氣濕度對各放電參數(shù)的影響,得到了這些參數(shù)隨空氣濕度變化的規(guī)律,這就是:電離系數(shù)隨濕度增大,較大的電場強度使這一影響更為顯著;低場強下附著系數(shù)隨濕度增大,高場強下隨濕度減。还庾游障禂(shù)隨濕度增大;電子和正離子漂移速度分別隨濕度增大和減小,大的電場強度使這一效應減小。此外,計算分析了濕度對導體外電離層的影響。結(jié)果表明,電離層半徑隨著濕度的增大而減小。 (3)基于電離層內(nèi)電荷數(shù)量密度一維數(shù)學模型,計算分析了濕度對電離層內(nèi)電流密度的影響,得到以下結(jié)果:對于大半徑正極性導體,電流密度均隨濕度減小,導體表面電場強度的增加使這一效應增強;對于小半徑正極性導體,電流密度隨濕度的變化基本上呈現(xiàn)先減小后增大的特征。電流密度隨濕度減小時,導體表面電場強度的增大使這一效應減弱。電流密度隨濕度增大時,導體表面電場強度的增大使這一效應增強。對于負極性導體,電流密度均隨濕度增大,且這一效應隨導體表面電場強度增大而增大。 (4)湯生第二電離系數(shù)是描述負直流電暈放電的一個關(guān)鍵參數(shù)。本文研究了不同濕度下,導體表面水分子的吸附對導體逸出功的影響,在此基礎(chǔ)上給出了一個考慮空氣濕度的湯生第二電離系數(shù)的計算方法,應用該方法計算的結(jié)果與實驗符合很好。這一方法對于考慮導體表面水分子吸附時導體放電的研究具有重要的理論意義。 (5)Peek公式由于它的簡單和解析的特點,長期以來一直被用來估計導體電暈起始場強。然而,該公式的局限是未考慮空氣濕度的影響。目前,尚未有一個較好地估計考慮空氣濕度影響的電暈起始場強的解析表達式。基于對導體電暈起始場強的分解,對考慮濕度的電暈起始場強的構(gòu)成作了理論分析和推導,結(jié)合應用導體電暈起始判據(jù)的不同濕度下的電暈起始場強的系統(tǒng)的數(shù)值計算,對Peek公式作了修正,分別給出了考慮空氣濕度的正極性和負極性導體電暈起始場強計算的修正的Peek公式;谛拚腜eek公式計算的不同濕度電暈起始場強與報道的實驗結(jié)果符合很好。因此,本文給出的修正的Peek公式為不同空氣濕度下的導體電暈起始場強提供了一個有效可行的理論估計。 (6)基于本文給出的修正的Peek公式,系統(tǒng)地計算分析了空氣濕度對電暈可聽噪聲、電暈損耗以及無線電干擾等電暈效應的影響,得到了如下結(jié)果。 濕度對電暈可聽噪聲的影響:對于不同半徑正極性導體,大的半徑和小的半徑下A聲計聲功率級(PWL)分別隨濕度減小和增大。對于不同半徑負極性導體,PWL基本上隨濕度增加,只是與大半徑導體相比,對于小半徑導體濕度對PWL的影響更為顯著。對于不同半徑和不同極性的導體,濕度對Lso聲級(SLA)的影響基本一致,即SLA隨濕度的增加而增加。 濕度對電暈損耗的影響:對正極性導體,大半徑和小半徑導體的電暈損耗分別隨濕度減小和增大。對于負極性導體,大半徑導體的電暈損耗隨濕度的增加先減小后增大,小半徑導體的電暈損耗隨濕度增大。 濕度對電暈無線電干擾水平的影響:正極性導體電暈產(chǎn)生的無線電干擾水平隨濕度減小。對于大半徑導體以及大的導體表面電場強度,濕度對無線電干擾水平的影響顯著。對于小半徑導體,這一變化很小,且?guī)缀醪皇軐w表面電場強度的影響。
[Abstract]:The implementation of power transmission from west to east energy strategy of our country, the country has been put into operation of high pressure and ultra high voltage DC transmission lines and a plurality of different levels. The need to consider the UHVDC corona discharge of transmission process. The corona discharge will not only increase the loss of power lines, can cause radio interference, audible noise of a series of environmental problems. With the continuous development of economy, environmental problems have attracted more and more attention, and is restricted by the strict environmental regulations. This makes the corona discharge become DC transmission line structure, factors that influence the construction cost. The transportation distance of UHVDC transmission lines in China, along the terrain, topography and meteorology the condition is complex, inevitably requires high humidity areas. Therefore, study on the influence of air humidity on DC corona discharge has important theoretical significance and practical significance.
This paper studies the effects of air humidity on conductor corona discharge were analyzed systematically. The parameters of air humidity on corona discharge control properties, such as ionization coefficient, friction coefficient, photon absorption coefficient, influence of electron and ion drift coefficient and ionospheric radius. The decomposition of conductor corona onset electric field based on simulation the theoretical analysis and field considering corona onset corona inception of the humidity field, correction of Peek formula. Combined with the modified Peek formula is given in this paper, systematically analyzed influence of humidity on corona effect. This paper mainly contains the following contents and results:
(1) the composition and characteristics of ambient air and the physical processes such as ionization and adhesion in the corona discharge are introduced. On this basis, the corona discharge mechanism of positive and negative conductor is described, and the one-dimensional mathematical model of the number density distribution of positive and negative conductor ionosphere is described.
(2) the nature of the corona discharge associated with multiple parameters, namely the ionization coefficient, friction coefficient, photon absorption coefficient, electron drift velocity and positive ion drift velocity. Therefore, effects of air humidity on corona discharge properties by the influence of these parameters to generate various discharge parameters on the wet air. Based on the corresponding in the dry air and water vapor decomposition, systematic calculation and Analysis on influence of air humidity on the discharge parameters, obtained the law of these parameters with the variation of air humidity: the ionization coefficient with increasing humidity, electric field intensity of the larger the effect is more significant; low field strength adhesion coefficient with increasing humidity. Under high electric field with the humidity decreases with increasing humidity; photon absorption coefficient; electron and positive ion drift velocity respectively with increasing humidity and reduced electric field strength large this effect decreases. In addition, calculation analysis The effect of humidity on the outer ionosphere of the conductor shows that the radius of the ionosphere decreases with the increase of humidity.
(3) the charge number density of one dimensional mathematical model based on the analysis of the influence of humidity on the ionospheric current density calculation, get the following results: for large radius positive conductor current density increased with the increase of humidity decreases, the surface electric field strength of conductor makes this effect enhancement; for small radius anode conductor, current density with the change of moisture basically characterized first decrease and then increase. The current density decreases with increasing humidity, electric field intensity on the surface of the conductor. The current density effect decreases with increasing humidity, increase the surface electric field strength of conductor makes this effect enhanced. For the negative conductor, the current density increases with increasing humidity. The effect with the conductor surface field strength increases.
(4) second students ionization coefficient is a key parameter to describe the decoction of negative DC corona discharge. This paper studied the effects of different humidity, the adsorption of water molecules on the surface of conductor conductor work, on the basis of this gives a consideration of air humidity second Townsend ionization coefficient calculation method, calculated by this method the results are consistent with experimental data. This method has important theoretical significance for the study of the conductor and the conductor surface discharge water molecular adsorption is considered.
(5) Peek formula due to its characteristics of simple and analytical, has long been used to estimate the conductor corona onset electric field. However, the formula is limited without considering the effect of air humidity. At present, there is not yet a better estimate of the analytical expression of the effect of air humidity on corona onset electric field considering the decomposition of conductor corona. The initial field based on considering corona inception field strength humidity are analyzed and deduced, combined with the numerical system of corona inception field strength and different humidity application conductor corona onset criterion under the calculation of the Peek formula was modified. The modified Peek formula to calculate the air humidity of the positive and negative polarity conductor corona onset considering the field are given. The calculation formula of Peek based on the different humidity corona inception field strength with the reported experimental results are in good agreement. Therefore, the proposed modified The Peek formula provides an effective and feasible theoretical estimate for the starting field intensity of conductors at different air humidity.
(6) based on the modified Peek formula given in this paper, the influence of air humidity on corona audible noise, corona loss and radio interference is systematically calculated and analyzed, and the following results are obtained.
Influence of humidity on corona audible noise for different radius positive conductor, large and small radii of A sound sound power level (PWL) respectively with humidity decrease and increase. For different radius negative conductor, PWL basically with the increase of humidity, but with a large radius conductor compared to effects on small radius the conductor of humidity on PWL is more significant. For different radius and conductors of different polarity, humidity on level Lso (SLA) effect is consistent, namely SLA increased along with the increase of humidity.
Effect of humidity on corona loss of positive conductor corona loss, large radius and small radius conductor respectively with the humidity decrease and increase. For the negative conductor corona loss, large radius of conductor along with the increase of humidity decreases first and then increases, the small radius of conductor corona loss with increasing humidity.
Influence of humidity on corona radio interference level: radio interference level positive conductor corona with humidity decreases. For large radius of conductor and the conductor surface field strength, the influence of humidity on the radio interference level significantly. For small radius of conductor, this change is very small, and almost not affected by the surface field strength of conductor.
【學位授予單位】:山東大學
【學位級別】:博士
【學位授予年份】:2014
【分類號】:TM851
【參考文獻】
相關(guān)期刊論文 前4條
1 惠建峰;關(guān)志成;王黎明;麻敏華;李秋瑋;;正直流電暈特性隨氣壓和濕度變化的研究[J];中國電機工程學報;2007年33期
2 卞星明;惠建峰;黃海鯤;王黎明;關(guān)志成;陳勇;;氣壓濕度對負直流電暈特性影響的研究[J];中國電機工程學報;2010年04期
3 張順福;瞿雪娣;;±500kV直流線路對無線電、電視及可聽噪音影響的研究[J];電力技術(shù);1985年04期
4 張運洲;呂健;;我國未來同步電網(wǎng)的戰(zhàn)略構(gòu)想[J];中國電力;2006年03期
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