基于能量平衡理论的连续触发喷射气流灭弧间隙熄弧效果研究

发布时间：2018-05-08 05:12

本文选题：架空线路 + 交流电弧　；参考：《广西大学》2017年硕士论文

【摘要】：并联间隙是架空线路上常用的一种雷电防护方式,可以有效的保护线路绝缘子免受交流电弧烧蚀,但由于其缺乏熄弧能力,容易造成输电线路跳闸,影响供电稳定性。为有效熄灭输电线路交流电弧,并且防止其因交流电源或多次回击导致电弧重燃,大幅降低雷击跳闸率,研制了一种连续触发喷射气流灭弧间隙。该装置通过连续触发的两次高速气流,在熄灭电弧的同时持续加速弧道对流散热,抑制电弧重燃。同时,针对多次回击引起弧道重燃的情况,装置通过快速的切换灭弧能量体做到气流与回击一一对应,抑制重燃。本文首先基于爆炸力学的C-J理论,研究了灭弧间隙内喷射气流产生的机理,建立了高速高压的气流冲击波数学模型。然后基于电弧能量平衡理论,分析了交流电弧熄灭的机理,研究了电弧通道能量散失的三种途径,建立了气流耦合电弧的模型。通过ANSYS Fluent软件对喷射气流熄灭交流电弧并抑制其重燃的全过程进行数值模拟,对前文建立的模型进行数值求解。经过仿真,7.1 ms时,电弧通道的平均温度Ta首次低于3000K,电弧熄灭,之后喷射气流继续对整个通道对流散热,抑制电弧重燃。在实验室环境下,模拟了装置单次熄弧试验与多次触发实验。实验结果表明,连续触发喷射气流灭弧防雷间隙可在8 ms内熄灭电弧,并且对于间隔时间大于20.7 ms的两次闪击,装置均可通过对灭弧能量体的重复触发以熄灭重燃的交流电弧。连续触发喷射气流灭弧间隙目前已试运行于两条线路。根据运行记录,试运行线路雷击跳闸率、雷击事故率大幅下降,并能够防护住200kA级雷电的多次回击。
[Abstract]:Parallel gap is a commonly used lightning protection method on overhead lines, which can effectively protect insulators from AC arc ablation. However, due to its lack of ability to extinguish arc, it is easy to cause tripping of transmission lines and affect the stability of power supply. In order to effectively extinguish the AC arc of the transmission line and prevent the arc reburning caused by AC power supply or multiple backstrokes, and to greatly reduce the lightning tripping rate, a continuous trigger jet arc interrupter gap is developed. This device can continuously accelerate the convection and heat dissipation of the arc channel while extinguishing the arc through two continuous triggered high speed airflow, so as to restrain the reburning of the arc. At the same time, in view of the reburning of the arc channel caused by multiple backstrokes, the device can quickly switch the arc-extinguishing energy body to match the airflow and the return stroke one by one, so as to suppress the reburning. In this paper, based on the C-J theory of explosion mechanics, the mechanism of jet flow in interrupter gap is studied, and the mathematical model of airflow shock wave at high speed and high pressure is established. Then based on the theory of arc energy balance, the mechanism of AC arc extinction is analyzed, three ways of energy dissipation in arc channel are studied, and the model of airflow coupled arc is established. The whole process of jet flow extinguishing AC arc and suppressing its reburning is numerically simulated by ANSYS Fluent software, and the numerical solution of the model established above is carried out. After emulation for 7.1 Ms, the average temperature of the arc channel is lower than 3000K for the first time, and the arc is extinguished, and then the jet flow continues to dissipate the heat of the whole channel and restrain the reburning of the arc. In the laboratory environment, single arc extinguishing test and multiple trigger test are simulated. The experimental results show that the lightning gap can be extinguished within 8 Ms, and for two flashes whose interval time is greater than 20.7 Ms, the device can extinguish the reburning AC arc by repeatedly triggering the arc extinguishing energy body. The continuously triggered jet arc-extinguishing gap has now been tested on two lines. According to the operation record, the lightning tripping rate and the lightning accident rate of the trial operation line are greatly reduced, and the lightning strike rate of 200kA grade can be protected against multiple lightning strikes.
【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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