雾对短空气间隙与绝缘子交流放电特性影响研究

发布时间：2018-06-29 16:48

本文选题：输电线路 + 外绝缘　；参考：《重庆大学》2014年博士论文

【摘要】：运行经验表明，雾中外绝缘放电对我国电网的安全和稳定运行构成了巨大威胁。国内外采用蒸汽雾研究了输电线路绝缘子的电气特性，但尚未系统开展自然雾及其电导率对输电线路外绝缘影响的研究。因此，系统研究输电线路绝缘子与空气间隙交流雾闪特性及其影响规律有助于更深入地认识雾闪的本质规律，对湿雾天气中输电线路外绝缘防雾闪和保障电网的安全运行具有重要的参考意义。在国家重大基础研究发展计划973项目的资金支持与国内外研究成果的基础上，论文在重庆大学高电压实验室和雪峰山试验站对输电线路绝缘子与棒－板短空气间隙交流雾闪特性进行了系统的研究分析，，得到的主要成果有：根据雪峰山试验站自然环境的测量结果，统计近4年试验站的月平均雾天气分布与雾物理特征，使用最小二乘法拟合液态水含量、雾滴浓度综合影响的能见度计算公式；采用雾发生装置产生模拟雾方法开展了瓷、玻璃绝缘子交流雾闪试验，其结果较蒸汽雾闪络电压高6.8%～7.2%；比较分析了染污方式对复合绝缘子交流雾闪特性的影响，即定量涂层法与喷涂法试验结果的百分偏差为7.1%～9.3%，可忽略染污方法对污秽特征指数的影响。基于人工模拟与自然环境试验，分析了雾物理特征（雾的水含量、雾水电导率与雾水温度）以及环境参数对棒－板短空气间隙交流击穿电压的影响规律。结果表明，雾的水含量在1～3g/m3时，击穿电压增大了5.1%；而雾的水含量在3～4g/m3时无明显变化；雾水电导率从100μS/cm增加至5150μS/cm时，击穿电压减小了2.7%～9.1%。根据试验结果及其分析，提出了浓雾地区雾水电导率对绝缘子交流闪络电压的附加影响规律，即绝缘子表面污秽度达Ⅲ级及以上严重污秽等级时（盐密≥0.15mg/cm2），雾水电导率不影响其闪络电压；而对于Ⅰ级及以下污秽等级（盐密≤0.06mg/cm2），雾水电导率从0.01mS/cm升至3.0mS/cm时将导致绝缘子交流闪络电压降低4.1%～25.6%。即严重污秽时可以不考虑雾水电导率的影响，清洁、轻度污秽时却存在明显影响；清洁、轻污秽绝缘子在高电导率浓雾环境中的交流闪络电压须进行校正，随着雾水电导率的增加（0.01～3.0mS/cm），校正系数K为1.00～0.80，雾水电导率对憎水性绝缘子交流闪络电压的影响小于亲水性绝缘子。根据测量结果，分析了绝缘子表面凝露与湿润特性，基于此建立了雾水电导率影响的附加盐密与预染污盐密的综合等值盐密计算模型，并提出了盐密、雾水电导率附加盐密综合影响的绝缘子交流闪络电压计算模型，模型计算结果与试验结果很吻合，百分偏差小于6.8%；分析了0级污秽时雾水电导率对四种绝缘子交流闪络电压梯度的影响。研究结果可为重污染浓雾地区绝缘子的污秽等级划分提供参考建议。根据雪峰山试验站基地开展的自然雾中绝缘子交流闪络试验结果，提出了盐密和环境温度综合影响的绝缘子交流闪络电压计算公式，与重庆大学青藏铁路高海拔沿线的试验结果吻合；提出与冻雾闪相比，复合绝缘子凝雾交流闪络时贯穿绝缘子两端的闪络电弧的持续时间明显变短，这主要由于冻雾时绝缘子伞群表面粗糙度发生改变，电弧将融化其表面冻结的雾滴而延长闪络时间，使电弧的形状极不规则，而呈现出弯曲或摇摆的剧烈燃烧现象。
[Abstract]:The operation experience shows that the insulation discharge of the fog is a great threat to the safe and stable operation of the power grid in China. The electric characteristics of the transmission line insulators are studied by steam fog at home and abroad, but the influence of natural fog and electrical conductivity on the external insulation of the transmission lines has not been systematically carried out. The characteristics of air gap AC flicker and its influence rules are helpful to understand the essential law of fog flicker more deeply. It is of great significance for the safe operation of transmission lines outside the transmission lines in wet fog and the safe operation of the power grid.
On the basis of capital support and domestic and foreign research results of national major basic research and development plan 973 project, the paper studies and analyses the communication flashover characteristics of transmission line insulators and rod plate short air gap in high voltage laboratory and Xuefeng mountain test station of Chongqing University. The main achievements are as follows:
According to the measurement results of the natural environment of the Xuefeng mountain test station, the monthly mean fog weather distribution and the physical characteristics of the fog in the last 4 years are calculated. The formula of the visibility calculation by the least square method is used to fit the liquid water content and the fog droplet concentration, and the fog flashover of porcelain and glass insulators is carried out by using the fog generator to produce the simulated fog method. The results are 6.8% to 7.2% higher than that of the steam fog flashover voltage, and the influence of the dyeing mode on the AC flashover characteristics of composite insulators is compared and analyzed. The deviation of the results of the quantitative coating method and the spray method is 7.1% to 9.3%, and the influence of the contamination method on the pollution characteristic index can be ignored.
Based on artificial simulation and natural environment test, the effects of fog physical characteristics (fog water content, fog water conductivity and fog water temperature) and environmental parameters on the AC breakdown voltage of rod plate short air gap are analyzed. The results show that the breakdown voltage increases by 5.1% when the water content of fog is from 1 to 3g/m3, while the water content of fog is from 3 to 4g/m3. The breakdown voltage decreased by 2.7% to 9.1%. when the conductivity of fog water increased from 100 S/cm to 5150 S/cm.
According to the test results and analysis, the additional influence of the fog water conductivity on the AC flashover voltage of insulators is put forward, that is, when the contamination degree of the insulator reaches the grade III and above the serious pollution level (salt density more than 0.15mg/cm2), the electrical conductivity of the fog water does not affect the flashover electric pressure, but the contamination level of the level I and below (salt density less than 0.06) Mg/cm2), when the electrical conductivity of the fog rises from 0.01mS/cm to 3.0mS/cm, the AC flashover voltage of the insulator will be reduced by 4.1% to 25.6%., that is, the influence of the electrical conductivity of the fog is not considered when the fog is seriously polluted, but there is a clear effect on the cleaning and light pollution; the AC flashover voltage of the clean, light polluted insulator in the high conductivity dense fog environment must be corrected. With the increase of the electrical conductivity of the fog (0.01 ~ 3.0mS/cm), the correction coefficient K is 1 ~ 0.80. The influence of the fog water conductivity on the AC flashover voltage of the hydrophobicity insulators is less than that of the hydrophilic insulators.
Based on the measurement results, the surface condensation and wetting characteristics of insulators are analyzed. Based on this, a comprehensive equivalent salt density calculation model of additional salt density and pre stained salt density is established, and a calculation model of insulator flashover voltage is proposed, and the calculation results and experiments of the model are put forward. The results are very consistent and the percentage deviation is less than 6.8%. The influence of the fog water conductivity on the AC flashover voltage gradient of the four insulators in the 0 grade pollution is analyzed. The results can provide a reference for the pollution grade division of the insulators in heavy polluted dense fog area.
According to the result of the AC flashover test of the insulators in the natural fog of the Xuefeng mountain test station base, the formula for calculating the AC flashover voltage of the insulator with the comprehensive influence of the salt density and the ambient temperature is put forward, which is in agreement with the experimental results along the high altitude along the Qinghai Tibet Railway in Chongqing University. The duration of the flashover arc running through the insulators is obviously shorter, which is mainly due to the change of the surface roughness of the insulators' umbrella group. The arc will melt the frozen droplets on the surface of the insulator to prolong the flashover time, making the shape of the arc extremely irregular, and presents a violent burning phenomenon of bending or rocking.
【学位授予单位】：重庆大学
【学位级别】：博士
【学位授予年份】：2014
【分类号】：TM216

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