特高压GIS隔离开关开合短母线仿真研究

发布时间：2018-01-26 23:18

本文关键词： 特高压 GIS隔离开关 VFTO 重复击穿　出处：《沈阳工业大学》2017年硕士论文　论文类型：学位论文

【摘要】：随着我国特高压电网的发展,GIS变电站以其自身的优点得得到了广泛的应用,但GIS隔离开关开关的操作会产生特快速瞬态过电压(VFTO),对电气设备的绝缘构成严重威胁。本文课题来源于“特高压GIS变电站VFTO关键技术研究”项目,针对隔离开关触头设计对VFTO的影响进行了深入研究。通过求解特高压GIS隔离开关三维电场,计算触头间隙电场分布,依据流注击穿判据,获取特高压GIS隔离开关触头间隙击穿电压曲线;根据理论分析,构建隔离开关间隙击穿燃弧和熄弧判定条件,以国标“交流隔离开关和接地开关”为依据,采用EMTP/ATP电磁暂态仿真软件,搭建特高压GIS隔离开关开合短母线时的重复击穿全过程电磁暂态仿真模型,仿真分析隔离开关分合闸操作全过程的影响因素。(1)分析特高压GIS隔离开关操作时VFTO形成机理,研究隔离开关电弧模型参数对VFTO的影响。仿真表明,触头间隙击穿延时增大时,VFTO陡度逐渐变小;稳态燃弧电阻越大,VFTO电压波形衰减越快,并对VFTO具有一定程度的抑制作用。(2)采用有限元方法计算特高压GIS隔离开关三维电场,依据流注击穿判据理论获得不同间隙距离下的击穿电压值,击穿电压随间隙距离近似呈线性增长关系;通过对隔离开关重复击穿过程机理分析,获得间隙击穿燃弧和熄弧判定条件,根据GIS元件等效模型,搭建重复击穿仿真模型,通过分合闸仿真可知,隔离开关电源侧电压波形是高频振荡脉冲与正弦电压的叠加,负载侧电压波形呈现台阶状,每次击穿时,击穿电压越大,产生的高频振荡脉冲幅值越大,最大振荡脉冲幅值约为1.2p.u,因此在间隙距离比较大时,产生较大幅值的VFTO;操作过程多次产生高频暂态电流VFTC,分闸过程幅值逐渐增大,合闸过程中VFTC幅值逐渐减小。(3)重复击穿过程影响因素研究。通过分析特高压GIS隔离开关间隙电场分布影响因素,仿真计算不同触头曲率半径下的间隙电场可知,曲率半径越大,间隙击穿电压越大;然后将不同触头形状下的击穿电压曲线带入重复击穿仿真模型进行仿真分析,由概率统计可知,触头曲率半径越大,分合闸过程中产生大幅值VFTO的概率增加,击穿次数和重复击穿持续时间逐渐减少;最后仿真不同短母线残余电压下的合闸过程可知,残余电压幅值越高,线路产生的VFTO值越大,击穿次数和重复击穿持续时间逐渐增多。
[Abstract]:With the rapid development of China's UHV power grid, GIS substation with its own advantages it has been widely used, but GIS disconnector switch operation will produce very fast transient overvoltage (VFTO), which poses a serious threat to the insulation of electrical equipment. This paper is from the "high pressure GIS" Research on Key Technology of substation the VFTO project, aimed at isolating switch contact design on the VFTO effect of the in-depth study. By solving the three-dimensional electric field of UHV GIS isolation switch, calculate the distribution of electric field on the basis of contact, streamer breakdown criterion, to obtain GIS extra high voltage isolating switch contact gap breakdown voltage curve; on the basis of theoretical analysis, construction of isolation switch breakdown arc extinguishing and arc conditions, to the national standard "AC isolating switch and grounding switch" as the basis, using the electromagnetic transient simulation software EMTP/ATP, build GIS ultra high voltage isolation switch switching short bus The electromagnetic transient simulation model of repeated breakdown of the whole process, the simulation analysis of influencing factors of opening and closing switch operation in the whole process. (1) analysis of UHV GIS isolation switch operation mechanism of VFTO, a parametric study of the effects of VFTO isolation switch arc model. Simulation results show that the contact gap breakdown delay increases, VFTO gradient becomes smaller steady state; arc resistance is VFTO, voltage waveform attenuation is fast, and has a certain degree of inhibition of VFTO. (2) by using the finite element method to calculate the UHV disconnector in GIS three-dimensional electric field, on the basis of streamer criteria theory to obtain the breakdown voltage under different gap distance value, the breakdown voltage increases linearly with the gap the approximate distance; through the analysis of the mechanism of repeated isolation switch breakdown process, obtain the gap breakdown arc and arc quenching conditions, according to the GIS model, build the simulation model of repeated breakdown, By switching simulation, isolating switch power supply side voltage waveform is the high frequency oscillation pulse superposition and sinusoidal voltage, load voltage waveform is stepped, each breakdown, the breakdown voltage increases, the high frequency oscillation pulse amplitude increases and the maximum oscillation amplitude is about 1.2p.u, so the gap is relatively large have a greater amplitude of VFTO; the operation process produced several high frequency transient current VFTC, breaking the amplitude increases gradually, the process of closing the VFTC amplitude decreased gradually. (3) study on the influencing factors of repeated breakdown process. Through the analysis of influence factors of UHV disconnector in GIS the distribution of electric field, electric field simulation shows different radius of curvature of the contact the radius of curvature, the greater the greater the gap breakdown voltage; then the breakdown voltage curves of different shapes into repeated contact breakdown simulation model by analysis. Statistics show that the radius of curvature of the contact, increase the probability of VFTO amplitude switching process, breakdown times and repeat breakdown duration decreased gradually; the closing process of the simulation of different short bus residual voltage of the residual voltage amplitude is higher, the line produces a larger VFTO value breakdown times and repeat the breakdown duration gradually increased.

【学位授予单位】：沈阳工业大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TM564.1

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