小电流直流电弧的动态模拟及其稳态特性研究  

Study on dynamic simulation and steady-state characteristics of small current DC arcs

作　　者：朱冠南 杨晓艺 高宇航 钟昱铭 熊兰[1] 周林[1] Zhu Guannan;Yang Xiaoyi;Gao Yuhang;Zhong Yuming;Xiong Lan;Zhou Lin(State Key Laboratory of Power Transmission Equipment&System Security and New Technology,Chongqing University,Chongqing 400044,China)

机构地区：[1]重庆大学输配电装备及系统安全与新技术国家重点实验室

出　　处：《电测与仪表》2020年第1期42-48,共7页Electrical Measurement & Instrumentation

基　　金：国家自然科学基金资助项目(51477021)

摘　　要：直流电弧故障一旦发生,由于无过零点阶段,电弧不易熄灭,将严重危害直流供配电系统的安全运行,因此有必要研究小电流直流故障电弧的电气特性与温度场分布。电弧发展过程较为复杂,涉及电场、磁场、流体场与热力场等多个物理场的变化,建立了直流电弧的磁流体动力学模型,通过有限元分析方法模拟了电弧的发展过程,得到了直流电弧不同发展阶段的电弧电压、温度分布变化特点。同时,建立了电弧等效电阻的数值拟合模型,通过该模型获得的电弧电阻特性变化规律与实验数据基本吻合,电弧电阻与电弧电流呈反比例特性。分析了直流电弧稳态特性的影响因素,证明了电弧电流、电极间距是决定电弧特性的主要因素。以上研究结果为小电流直流电弧特性研究提供了新思路,为直流电弧的检测及保护装置的研究提供理论支持。Once DC arcs faults happen,arcs will not extinguish themselves easily for the reason that the DC current does not reach zero value,which is extremely dangerous for the operation of DC power distribution system. Thus,studying the electrical characteristics as well as temperature distribution of small-current DC arcs is of great necessity. The development of arcs is complex,relating to electric fields,magnetic fields,fluid fields and temperature fields and so on. In this paper,the model of DC arcs based on magneto-hydrodynamics(MHD) is introduced. Through finite element analysis method,we simulated the developing process of DC arcs to get arc resistances and temperature distributions at different stages during development. Additionally,the numerical fitting model for equivalent resistance of arc is established. The regularities and characteristics of arc resistances obtained from the model accords with the experimental results,which the arc resistance is inversely proportional to its current. Finally,we analyze the factors that are able to affect the characteristics of DC arcs in steady state,proving that the arc current and the electrode distance are key factors. The research results mentioned above provide new ideas for studying small-current DC arcs and theoretical support for DC arc detection as well as equipment protection.

关 键 词：直流 电弧 磁流体动力学 电弧电阻 温度场 

分 类 号：TM93[电气工程—电力电子与电力传动]