基于冲击波正反射理论的半封闭结构灭弧特性研究  

Arc-extinguishing characteristics of semi-enclosed structures based on theory of positive shock wave reflection

作　　者：陈宇宁 王巨丰[1] 杨子童 李庆一 CHEN Yu-ning;WANG Ju-feng;YANG Zi-tong;Li Qing-yi(Sclool of Electrical Engineering,Guangxi University,Nanning 530004,China)

机构地区：[1]广西大学电气工程学院,广西南宁530004

出　　处：《广西大学学报（自然科学版）》2022年第2期399-405,共7页Journal of Guangxi University（Natural Science Edition）

基　　金：广西壮族自治区科技攻关计划(AA18242050)。

摘　　要：由于雷电流在泄放过程中会引起绝缘电位差升高,导致接地网出现高电位差,威胁人身安全以及设备的正常运行。为降低杆塔接地电位差,采用半封闭结构压缩电弧产生冲击波,并在冲击波触壁后二次压缩气体形成反射波,以波叠加作用破坏电弧的发展。本文首先通过冲击波正反射理论,分析计算了峰值为10 kA的8/20μs冲击电流产生的正反射波超压值可达4.8 MPa;其次,建立二维轴对称的冲击放电模型,对结构的大电流冲击放电过程进行仿真;最后,进行半封闭结构电流冲击试验。仿真结果显示在10μs半封闭结构内最大压强达4.38 MPa,在80μs左右电导率降至0;试验结果测得冲击电流幅值由9.54 kA衰减到5.72 kA,并在65μs左右电流降至0。仿真与试验结果都表明,半封闭结构能有效熄弧并限制绝缘电位差升高。Lightning current in the process of discharge can cause the ground potential to rise,leading to a large ground potential difference that hinders the normal operation of the equipment.To reduce the ground potential difference in case of a lightning strike,this study proposes a semi-enclosed structure to limit the rise in the ground potential.Lightning-induced overvoltage causes the semi-enclosed structure to discharge,forming an arc channel.Because the arc is compressed by the structure,and owing to the thermal effect of the gas being squeezed in the original structure,an overpressure-induced shock wave is generated.Positive reflection occurs when the shock wave hits the wall,and the secondary compressed gas forms a reflected wave that damages the development of the arc through superposition.By using the theory of positive reflection of shock waves,the overpressure due to a positively reflected wave,generated by an impulse current of 8/20μs with a peak value of 10 kA,was as high as 4.8 MPa,48 times the initial pressure.Moreover,a two-dimensional axisymmetric shock discharge model was established in COMSOL to simulate the process of shock discharge of the structure in case of a large current.Finally,current-induced shock tests were carried out on the semi-enclosed structure.The results show that the maximum pressure in the semi-enclosed structure was 4.38 MPa at 10μs,and conductivity dropped to zero at 80μs.In experiments,the amplitude of the impulse current decreased from 9.54 kA to 5.72 kA,and current dropped to zero at about 65μs.The results show that the semi-enclosed structure can extinguish the arc and limit the rise in ground potential.

关 键 词：冲击波 冲击放电 半封闭结构 正反射 

分 类 号：TP273[自动化与计算机技术—检测技术与自动化装置]