颗粒荷电对绝缘子积污特性影响的数值模拟研究

发布时间：2018-04-28 19:59

本文选题：绝缘子 + 颗粒荷电　；参考：《华北电力大学》2017年硕士论文

【摘要】：大气中污秽颗粒在近输电线路的离子流场中荷电会影响绝缘子周围的电场分布,进而改变颗粒的运动轨迹,影响绝缘子表面的积污状况。因此,有必要研究污秽颗粒荷电对绝缘子积污特性和沿面电场的影响。本文概述了污秽颗粒主要的荷电机理,利用COMSOL对瓷三伞及复合绝缘子在颗粒不同荷电方式下风洞积污特性进行了数值模拟,将积污量的模拟与试验结果进行了对比分析,以验证数值模拟方法的合理性,并探究颗粒相对合理的荷电方式。籍此,对弱风和微风环境110kV直、交流输电线路中,瓷三伞绝缘子的自然积污特性进行了数值模拟,比较了不同风速和粒径下颗粒所受流体曳力、电场力和重力的力比,分析了风速、粒径和污秽浓度等因素对自然积污特性的影响;对清洁和污染环境中瓷三伞绝缘子沿面电场的数值模拟结果进行对比,探究了颗粒在荷电情况下粒径、数量、荷质比、极性等因素对该绝缘子沿面电场的影响。结果表明:1)本文所采用的数值模拟方法是合理的,颗粒“按比例”荷电方式相对而言更具合理性。2)直、交流电压作用下,随风速的增大,绝缘子表面整体积污量先增后减;随污秽浓度增加,积污量均增加且增速减缓,直流时增速大于交流。3)弱风(0.5~2m/s风速)时,直流电压作用下,积污量随粒径增大而增加,交流电压作用下,先增后减;微风(3~5m/s风速)时,直、交流电压作用下,均随粒径增大而增加。4)伞裙几何形状影响绝缘子沿面电势和场强分布,其曲线拐点对应绝缘子表面的特征拐点;各伞裙沿面电势和场强曲线在清洁和污染环境中差异较大。5)伞群场强最大值点发生位置不同:清洁环境发生于铸铁、空气及瓷三者交界;污染环境发生于主要特征拐点处。6)清洁和污染环境场强矢量方向不同:清洁环境从高压端出发终止于低压端;污染环境(粒径足够大)正荷质比时从中间伞裙出发终止于低压端或高压端,负荷质比反之。7)各伞裙沿面场强最大值随粒径、数量、正荷质比增大而增大。8)污染环境伞裙沿面场强最大值可达清洁环境的9~70倍,在一定的条件下易发生局部电弧。
[Abstract]:The distribution of the electric field around the insulator will be affected by the charged charge of the polluted particles in the ion flow field near the transmission line, which will change the moving track of the particles and affect the fouling condition on the surface of the insulator. Therefore, it is necessary to study the influence of the charging of contaminated particles on the fouling characteristics of insulators and the electric field along the surface. In this paper, the main charging mechanism of contaminated particles is summarized. The characteristics of fouling in wind tunnel under different charging modes of ceramic umbrellas and composite insulators are numerically simulated by COMSOL, and the results of simulation and test are compared and analyzed. In order to verify the rationality of the numerical simulation method and explore the relatively reasonable charging mode of particles. In this paper, the natural fouling characteristics of ceramic three-umbrella insulators in 110kV direct and AC transmission lines in weak wind and breeze environments are numerically simulated, and the fluid drag force, electric field force and gravity force ratio of particles under different wind speeds and particle sizes are compared. The effects of wind speed, particle size and pollution concentration on the characteristics of natural fouling are analyzed, and the numerical simulation results of the electric field along the surface of the porcelain three-umbrella insulator in the clean and polluted environment are compared, and the particle size and quantity under the condition of charge are explored. The effect of charge / mass ratio, polarity and other factors on the electric field along the insulator surface. The results show that the numerical simulation method used in this paper is reasonable, the particle "proportional" charging method is more reasonable than that of "proportional" charging mode. Under the action of AC voltage, with the increase of wind speed, the total amount of pollution on the surface of insulator increases first and then decreases. With the increase of pollution concentration, the amount of pollution increased and the growth rate slowed down. The DC speed was higher than that of AC. 3) when the wind speed was 0.5m / s), under DC voltage, the amount of fouling increased with the increase of particle size. Under the action of AC voltage, it increased first and then decreased. When the wind speed is 3 ~ 5 m / s), the geometric shape of umbrella skirt affects the distribution of electric potential and field strength along the surface of insulator, and the curve inflection point corresponds to the characteristic inflection point of insulator surface under the action of direct voltage and AC voltage, and the geometric shape of umbrella skirt affects the distribution of electric potential and field strength along the surface of insulator. The position of maximum field strength of each umbrella skirt is different in clean and polluted environment. 5) the location of maximum field strength of umbrella group is different: clean environment occurs at the junction of cast iron, air and porcelain; Pollution environment occurs at the main feature inflection point. 6) the direction of field intensity vector of clean and polluted environment is different: clean environment terminates from high pressure end to low pressure end; When the positive charge mass ratio of polluted environment (particle size is large enough), it ends at the low pressure end or high pressure end from the middle umbrella skirt, and the maximum field strength along the plane of each umbrella skirt depends on the particle size and quantity. The maximum field strength along the surface of the environmental umbrella skirt is 970 times of that in the clean environment, and local electric arc is easy to occur under certain conditions.
【学位授予单位】：华北电力大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TM216

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