雾霾对特高压直流输电线路电晕离子流场影响的研究

发布时间：2018-03-21 10:59

本文选题：特高压直流输电　切入点：雾霾　出处：《山东大学》2016年硕士论文　论文类型：学位论文

【摘要】：为保证能源供给和资源的充分利用,我国大力发展了远距离特高压输电技术。特高压直流输电线路由于电压等级高且标称电压的方向不变,在高场强和恶劣的气象条件下易导致电晕放电,形成电晕离子流场,由此对电磁环境带来的影响及相应的生态效应,已成为需要关注和研究的重要课题。作为近年来我国频繁发生的大气污染现象,雾霾发生时,空气中含有大量悬浮颗粒物,且不同湿度状况下含有不同量的雾滴,这些是引发线路电晕放电的关键因素。因此,开展雾霾天气下特高压直流输电线路的电晕放电和线路下方地面离子流场特性研究,具有重要的理论和实际意义。本文对雾霾天气下特高压直流输电线路的电晕离子流场进行了数值研究。建立了一个计及雾霾影响的描述特高压直流输电线路电晕离子流场的计算模型,对不同雾霾状况下,不同线路排布方式和不同极导线结构参数下,地面合成电场、离子流密度分布及其变化规律作了计算分析。本研究工作包含了以下的内容和结果：1.阐述了电晕放电的基本原理和特点,依据雾霾的特性提出将雾与霾区分的概念模型用于本文相关计算,从导线表面状况、起晕场强、离子迁移率三个方面来阐明不同湿度雾霾对电晕放电特性的影响机理。2.建立了一个雾霾条件下电晕发生时特高压直流输电线路离子流场的计算模型,并基于有限元方法,实现了线路下方的地面合成电场和离子流密度的计算。以±800kV特高压直流输电线路为研究对象,计算分析了不同雾霾状况对地面电晕离子流场的影响规律。结果表明：(1)高湿度的雾霾天气会使地面合成电场和电晕离子流密度随雾霾污染等级的增加而增大,且在污染等级较高时,两者最大值相对于正常天气的增大幅度随污染浓度呈近似的线性增加；(2)干霾或低湿度雾霾天气下,电晕离子流场呈现与高湿度情况相似的变化规律,只是相对于正常天气下的值,增加量很小；(3)雾霾发生时,湿度对电晕起始场强的影响和空间悬浮颗粒的荷电行为是使地面合成电场和离子流密度变化的主要原因。迁移率的变化则抑制了离子流密度的增加,因而离子流密度虽有增大,但均远小于国家标准所限定的最大值。3.考虑不同湿度和不同污染等级雾霾状况,并计及起晕过程的湿度效应和悬浮微粒的荷电机理,对±800kV同塔双回特高压直流输电线路,在不同的参数设计(导线排布方式、导线布置高度、水平间距、垂直间距)方式下的电晕离子流场进行了计算研究,结果表明：(1)同塔双回特高压直流输电线路的不同排布方式在4级及以下污染程度的雾霾天气中,电晕离子流场特性差别不明显。然而,随着雾霾污染程度进一步加剧至4级以上时,同极同侧垂直布置的线路对于抑制地面合成电场和离子流密度的变化表现出更明显的优势；(2)同塔双回线路各极导线选择大截面导体有利于弱化重雾霾天气下直流线路的电晕离子流场效应,但当雾霾污染等级达6级时,该效应会出现增强趋势,故实际工程中导线的外径不宜选择过大；(3)双回线路回线间距的增大不利于克服重雾霾天气对电晕离子流场造成的影响,因此回线间距在满足绝缘要求的前提下应当越小越好；而极导线间距的增加可在一定程度上补偿雾霾对电晕离子流场造成的影响,然而从节省线路走廊的角度来考虑,极间距又不宜过大；(4)导线最小对地高度对电晕离子流场特性的影响显著大于雾霾微粒的影响,线路最小对地高度的增加能够有效抑制雾霾天气下地面合成电场和离子流密度的增大。
[Abstract]:In order to make full use of ensuring the supply of energy and resources, China's vigorous development of long-distance UHV transmission technology. UHV DC transmission lines due to the high voltage and the nominal voltage of the same direction, resulting in corona discharge easily in the high field and bad weather conditions, the formation of corona ion flow field, the resulting impact on the electromagnetic environment and its ecological effect, has become an important subject in need of attention and research. As air pollution phenomenon in China in recent years, the frequent occurrence of fog and haze, containing a large number of suspended particles in the air, with different amounts and different humidity conditions of the droplets, which are key factors caused by line corona discharge. Therefore, study on the ground below the ion flow field characteristics of fog and haze under UHV DC transmission lines corona discharge and line, has important theoretical and practical significance. This paper on haze days Corona ion flow field of gas under UHV DC transmission lines are studied. A calculation model was established to describe the UHV DC transmission lines and the effects of haze corona ion flow field, on different haze conditions, different line arrangement and different pole structure parameters, the ground electric field, ion current density distribution and variation were calculated and analyzed. The research work includes the following contents and conclusions: 1. describes the basic principle and characteristics of corona discharge, according to the characteristics of the conceptual model of the haze of fog and haze for the distinction between related calculation, from the surface of the wire, corona electric field, ion mobility three aspects to clarify the mechanism of.2. in different humidity haze effect on corona discharge characteristics of a computational model of a haze under the condition of corona occurs when the UHVDC transmission line ion flow field Type, based on the finite element method, used to calculate the line below the ground total electric field and ion current density. The 800kV UHVDC transmission lines as the research object, analyze the influence law of different conditions on the ground haze corona ion flow field calculation. The results showed that: (1) increase in high humidity haze weather causes the ground electric field and corona ion current density with increasing levels of haze pollution, and pollution in higher level, both the maximum relative to normal weather increases with the increase of pollution concentration is approximately linear; (2) dry haze or fog and haze under low humidity, corona ion flow field presents similar changes with high humidity the only relative to the normal value of the weather, a very small amount of increase; (3) the occurrence of haze, influence of humidity on corona onset electric field and space charge behavior of suspended particles is the synthesis of electric ground The main reason for the density change of the ion flow field and increased. The change of the suppression of the ion current density, and ion current density is increased, the maximum value of.3. under different humidity and different pollution levels but the haze situation is far less than the national standard limit, humidity effect and suspended particles and the onset process the charging mechanism, the + 800kV double circuit on the same tower in UHV DC transmission lines, in different design parameters (conductor arrangement, conductor arrangement height, horizontal spacing, vertical spacing) corona ion flow field under studied, results showed that: (1) the same tower double circuit UHVDC transmission the different line arrangement in 4 and the following pollution haze weather, flow characteristics of corona ion did not differ significantly. However, with the haze pollution degree further to more than 4, are vertically arranged at the same side The line for change to suppress ground electric field and ion current density showed more obvious advantages; (2) double circuit lines on the same tower each pole conductor has the disadvantages of large section conductor corona ion flow field effect under heavy fog and haze of DC line, but when the haze pollution grade of 6, the effect will be enhanced the trend, so in actual engineering wire diameter should not be too large; (3) increase double circuit loop spacing is not conducive to overcome the impact of heavy fog and haze caused by corona ion flow, so the loop spacing in the prerequisite to meet the requirements of the insulation should be as small as possible; and increase the pole spacing can be affected in some degree on the compensation of haze caused by corona ion flow field, however the savings from the line corridor perspective, pole spacing and should not be too large; (4) minimum height of conductor of corona ion flow field It is significantly greater than the effect of haze particles, and the increase of the minimum ground height can effectively inhibit the increase of the surface synthetic electric field and the ion flow density in the haze weather.

【学位授予单位】：山东大学
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：TM75

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