SF_6短间隙中高频电弧的阻抗特性  

Impedance Characteristics of High-frequency Arc in Short SF_6 Gap

作　　者：李志兵[1] 李晓昂[2] 陈维江[3] 张乔根[2] 陈钢亮[2] 杨昊[2] 

机构地区：[1]中国电力科学研究院,北京100192 [2]西安交通大学电气工程学院,西安710049 [3]国家电网公司,北京100031

出　　处：《高电压技术》2013年第6期1411-1418,共8页High Voltage Engineering

基　　金：国家重点基础研究发展计划(973计划)(2011CB209405);国家电网公司科技项目([2011])~~

摘　　要：气体绝缘开关设备(GIS)中隔离开关操作时,触头间隙会出现高频放电,产生威胁电力设备安全的特快速暂态过电压(VFTO),高频电弧的阻抗特性对VFTO的上升沿和幅值等具有重要影响。为此,提出了利用SF6间隙研究GIS隔离开关高频电弧阻抗特性,分SF6短间隙和长间隙2个阶段开展工作的技术方案,并介绍了SF6短间隙阶段的研究工作。建立SF6短间隙和紧凑型RLC放电回路产生高频电弧。采用高压探头、Rogowski线圈、B-dot传感器分别测量电弧电压、电流及电流变化率,利用高速分幅相机观测电弧形态。提出了电弧电感和电阻的分析方法,研究了气压、弧长及电流对电弧电感和电阻的影响,建立了基于能量平衡关系的电弧电阻模型。研究结果表明:高频放电起始后,电弧电感从约13μH/m迅速减小并趋于稳定值约9μH/m;电弧电阻在约60ns内快速跌落至约1Ω,随后缓慢下降并趋于稳定值约0.1Ω;气压增大时电弧电感和电阻增大,电流增大时电弧电感和电阻减小;提出的模型能够计算全过程电弧电阻,计算结果与试验分析结果基本符合。In gas insulated switchgears （GIS）, very fast transient overvoltage （VFTO） generated by discharges between disconnector contacts threatens the safety of electric equipment seriously. Impendence characteristics of high-frequency arc have an important influence on VFTO waveforms in the rise time and amplitude, etc. We put forward a scheme that adopted SF6 gap to research the impedance characteristics in which the work would be carried out with short SF6 gap and then long gap, and introduced some researches on short SF6 gap. An impact RLC discharge circuit with a short SF6 gap was designed to generate high-frequency arc. High voltage probe, Rogowski coil, and B-dot sensor were used to measure arc voltage, arc current, and the variation ratio of current, respectively. High speed framing camera{ HSFC） was adopted to observe the arc shape. After proposing a method for analyzing the arc inductance and resistance, we discussed the influence of gas pressure, arc length, and current on the arc inductance and resistance, then put forward a mathematical model of arc resistance based on energy balance principle. The results show that, atter the initial discharge, the arc inductance decreases rapidly from 13 t^H/m to a stable value of 9/,H/m, meanwhile the arc resistance drops to 1 /1 within 60 ns, then deceases slowly to a stable value of 0.1 /1. The arc inductance and resistance increase with increasing gas pressure, and decrease with increasing current. The proposed mathematical model can be used to calculate the arc resistance of the whole process, and its calculation results fit well with those obtained from experiments

关 键 词：气体绝缘开关设备 特快速暂态过电压 SF6间隙 高频放电 电弧电感 电弧电阻 

分 类 号：TM595[电气工程—电器]