【作者】 姜旭；

【导师】 曹云东；

【作者基本信息】 沈阳工业大学 ， 电机与电器， 2009， 硕士

【摘要】 在开关电器的设计和研究中,电弧理论的研究是一项十分重要的课题。电弧是气体放电的一种形式,由气体击穿至形成电弧是一个非常复杂的物理过程。研究电弧的形成过程,可以更深刻地理解电弧产生和熄灭的本质,对断路器设计及其开断性能的研究具有重要的理论和实际意义。本文在电器电弧理论和气体放电理论的基础上,以平板和针板两种典型电极结构为例进行了探索和研究。对间隙击穿过程的仿真研究表明,平板电极间隙中的放电通道呈主、次放电通道并存模式,针板电极间隙中的放电通道呈电树枝模式。根据放电通道的特点,本文提出一种气体击穿动态发展模型,给出了有、无分枝两种放电通道中,宏观和微观各参数之间的变化和联系,实现了由气体击穿通道向电弧演变和发展的动态模拟。通过仿真研究,得到了不同结构间隙中,不同放电阶段,放电通道的形貌特征,对比了两种模式放电通道发展过程的异同点,并分析了电场分布、电压、电流以及表征微观电离、复合、扩散现象的综合系数对放电演变过程的影响规律。将气体击穿动态发展模型应用于真空灭弧室结构的研究中,得到了真空间隙击穿形成初始放电通道及其发展演变规律,并得到了击穿通道中电子、正离子数密度的变化规律,以及电子温度分布和通道半径的变化规律。通过对不同外加电流条件下放电演变过程的研究,证明了,随着外加电流的增大,真空电弧有由扩散型向集聚型发展的趋势,为深入解析真空电弧的变化规律奠定了基础,同时也证明了本文所提出的放电发展模型的正确性。更多还原

【Abstract】 The theories of arc play a very important role in the design and investigation of circuit breakers. Arc is a type of gas discharge, and the physical process from gas breakdown to arc is quite complicated. The studies of arc formation can provide a profounder understanding of the generation and extinguishment of arc, and have theoretical and practical significances for better design and improving the interruption performance of circuit breakers.Based on the theories of electric arc and gas discharge, research and exploration are carried out by taking the example of two typical electrode structures, flat-plate and pin-plate. The investigation and simulation on the breakdown of gap show that the discharge channel shape within the flat-plate electrode gap is the pattern of main and secondary discharge channels existing synchronously, while the discharge channel shape within the pin-plate electrode gap is the pattern of electrical trees.A dynamic evolution model of gas breakdown is proposed according to the characteristics of discharge channels. The varieties and relations of macroscopic and microcosmic parameters in the discharge channels with and without branches are described, and the simulation of dynamic evolution from gas discharge channel to arc is carried out. Moreover, the characteristics of discharge channel shapes in different electrode gap during each discharge stage are obtained. The similarities and differences of the development of the two pattern discharge channel are contrasted, and the influences of the relevant parameters including the distribution of electrical field, voltage , current and the integrated coefficient which is used to describe the microcosmic phenomena of ionization, recombination and diffusion during the process of the discharge channel development are analyzed.The dynamic evolution model is applied to the study of vacuum circuit breaker. The shapes and evolution roles of initial discharge channel formed in the breakdown of vacuum gap are obtained, and the variety roles of electron and the positive ion in the discharge channel are acquired. Moreover, the variety roles of the channel radiuses and the distributions of the electron temperature are also obtained. Through the investigation of discharge evolution under different applied current, the tendency that the shapes of vacuum arc change from diffused mode to constrictive mode with the increasing of the applied current is testified, establishing a foundation to the deep analysis of vacuum arc variety roles, and the correctness of the discharge model proposed in this thesis is proved.更多还原