爆炸气流作用下灭弧防雷间隙截断电弧机理对建弧影响的研究

发布时间：2019-04-10 14:35

【摘要】：当今社会飞速发展,所伴随着对电能的需求也越来越大,其中架空输电线路的安全运行对于电网-的稳定运行十分重要,所以高压输电线路对于雷电的防护变得极为重要。根据电网的输电线路实际运行统计表明,雷击是引发输电线路出现闪络而跳闸的重要因素,尤其在我国南方地区雷击事故频繁发生。本文为了大幅度降低雷击造成的跳闸事故发生率,针对一些传统的防雷理念的不足之处,提出并研发了一种可以利用爆炸气流来达到深度抑制建弧的防雷间隙。因此本文对爆炸气流抑制建弧的机理进行分析,建立了爆炸气流冲击波模型,将爆炸气流等同于爆炸冲击波来分析,同时从电弧的各项特性参数如温度,直径,电位梯度等出发,分析了电弧的发展变化。分析了电弧的能量变化过程,建立了电弧能量平衡模型,从能量角度对于电弧散热方式进行分析,主要有对流,辐射,热传导三种散热方式,结合爆炸气流灭弧的过程中,通过横吹和纵吹两种作用,加强了对流的作用,同时使得.电弧通道被改变,加强了电弧的对流散热,使电弧急速冷却,达到电弧熄灭的温度条件,使得对流散热功率远远大于产热功率,从而打破能量平衡,达到了建弧抑制的效果。其次,根据电弧能量平衡理论建立气流耦合电弧的模型,利用Fluent仿真软件对爆炸气流灭弧的全过程进行仿真模拟,得出其中的温度场和速度场的分布图,直观的表明了能量体被触发后产生了速度极高的气流并迅速膨胀至整个灭弧空间,持续冲击电弧使得电弧能量平衡迅速被彻底破坏,温度迅速下降至常温,有效抑制了建弧。另外,对爆炸灭弧防雷间隙进行了冲压试验和工频电弧抑制的试验,并使用高速摄像机对实验过程进行了拍摄和记录,得出熄灭工频电弧的所用时间为3.8ms,使得电弧在建弧阶段就被熄灭,通过理论和试验结合充分表明了研究成果的有效性。同时通过实际的挂网运行,对于电网输电线路的安全运行也取得了显著的成效。
[Abstract]:Nowadays, with the rapid development of society, the demand for electric energy is increasing. The safe operation of overhead transmission lines is very important to the stable operation of the power grid, so the high voltage transmission lines are very important for the protection of lightning and lightning. According to the actual operation statistics of transmission lines in power grid, lightning strike is an important factor causing flashover and tripping of transmission lines, especially in southern China. In order to greatly reduce the incidence of tripping accidents caused by lightning strikes, in view of the shortcomings of some traditional lightning protection concepts, this paper proposes and develops a kind of anti-lightning clearance which can be deeply restrained by explosive airflow. Therefore, this paper analyzes the mechanism of suppressing arc building by explosion gas flow, and establishes the blast wave model, which equates the explosion gas flow with explosion shock wave. At the same time, according to the characteristic parameters of arc, such as temperature and diameter, The electric potential gradient and so on are used to analyze the development and variation of arc. The energy change process of arc is analyzed, and the model of arc energy balance is established. The heat dissipation mode of arc is analyzed from the angle of energy, which mainly includes convection, radiation and heat conduction, combined with the process of arc suppression by explosive airflow. Through the action of horizontal blow and vertical blow, the effect of convection is strengthened, and at the same time, the effect of convection is enhanced. The arc channel is changed, which strengthens the convection heat dissipation of the arc, makes the arc cooling rapidly and reaches the temperature condition of arc quenching, which makes the convective heat dissipation power far greater than the heat generation power, thus breaking the energy balance and achieving the effect of arc-building suppression. Secondly, according to the theory of arc energy balance, the model of coupled gas flow arc is established, and the whole process of arc quenching is simulated by using Fluent simulation software, and the temperature field and velocity field are obtained, and the distribution diagram of the temperature field and velocity field is obtained. It is shown intuitively that the gas flow with extremely high velocity is produced after the energy body is triggered and expands rapidly to the entire arc extinguishing space. The arc energy balance is destroyed rapidly and the temperature drops to normal temperature, which effectively suppresses the arc construction due to the continuous impact of the arc. In addition, the stamping test and the power frequency arc suppression test were carried out on the explosion arc extinguishing clearance, and the experimental process was photographed and recorded by the high-speed camera. It was concluded that the time used to extinguish the power frequency arc was 3.8 Ms, and the time required to extinguish the power frequency arc was 3.8 Ms. The arc is extinguished in the arc-building stage, and the effectiveness of the research results is fully demonstrated by the combination of theory and experiment. At the same time, the safety operation of the transmission line is also achieved through the actual operation of the grid.
【学位授予单位】：广西大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TM863

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