【作者】 陶磊；

【导师】 董冰冰；

【作者基本信息】 合肥工业大学 ， 电气工程（专业学位）， 2024， 硕士

【摘要】 随着智能配电网的高速发展,开关设备除了满足常规的开断和关合要求,还出现大量快速控制和保护的特殊应用需求。传统电力开关设备合闸时间动辄数十毫秒,其快速控制和保护能力不足的问题明显;高电压大容量的电力电子开关动作时间快,但结构和控制较复杂、成本高昂。简单可靠,成本低,可控性强的等离子体喷射触发型气体间隙开关优势明显,然而为满足电力系统场景应用中高稳定性的工作要求,开关设备要求工作在极低工作系数下,而触发脉冲参数一般确定难以快速调整。目前,低定工作系数下的气体间隙开关触发放电特性尚不明显,与自击穿型气体开关相比,等离子体喷射型气体间隙开关的绝缘恢复特性是否存在显著差异,是一个值得深入探讨的问题。本文从气体间隙开关研究现状出发,采用试验探究和理论分析相结合的方式,对低定工作系数下的等离子体喷射型气体间隙开关触发放电特性,以及触通过程中的绝缘恢复特性进行了系统性研究,具有重要的科学意义和工程应用价值。论文主要工作及取得的成果如下:首先,探讨等离子体喷射触发型气体间隙开关的触发放电原理,并据此设计了触发腔结构。采用“电容放电+脉变隔离升压”的触发回路设计,搭建了气体间隙开关喷射等离子体触发放电实验研究平台,结合了光、电同步观测技术,构建喷射等离子体特征参数监测平台。此外,为了探究气体间隙开关触发放电过程中的快速绝缘恢复特性,设计并搭建了基于双脉冲法的绝缘恢复过程试验平台。然后,在低定工作系数下系统地改变了气体介质、间隙距离以及触发条件参数等,开展了气体间隙开关触发放电特性试验,并进一步探究开关触发放电过程的触发腔放电通道的电压电流和沉积能量特性。研究表明:低定工作系数下,仅改变气体介质的气体组分含量,气体间隙开关的触发导通时延并未发生显著变化,但其诱导击穿时刻存在差异;且不同气体组分含量下,喷射等离子体演化形态、特征参数存在明显差异。增大SF₆体积占比,气体开关触通时延增大,极限可触发工作系数及喷射等离子体轴向高度减小,轴向高度衰减率增大。开关主间隙距离对气体开关触发放电特性影响显著。提高触发电压,触发腔电弧通道电功率增大,弧道能量沉积效率降低,等离子体喷射高度增大,气体开关触通能力提升,其临界工作系数和触通时延均明显降低。触发腔沿面高度的增加会约束了电弧通道发展时的热沉积过程,电弧通道沉积能量渐进增大。最后,对喷射等离子体型气体间隙开关触发放电过程快速绝缘恢复特性进行研究,并获得了不同条件参数下气体间隙开关的绝缘恢复特性规律。研究表明:气体间隙开关绝缘恢复过程可分为过渡期、快速恢复期和饱和期3个阶段,饱和期的持续时间远大于前两阶段之和。减小开关间隙距离,气体开关绝缘恢复速率渐进增大,其绝缘基本恢复时间可降低50%;气压对气体开关绝缘恢复特性影响显著,对不同阶段的绝缘恢复过程的影响特性存在差异,增大气压会减缓气体开关的绝缘恢复过程。强电负性SF₆对气体开关绝缘恢复具有明显增强作用,其绝缘恢复速率接近于干燥空气中的4倍,具有优异的绝缘恢复性。更多还原

【Abstract】 With the rapid development of smart distribution network,in addition to meeting the requirements of conventional switching and closing,there are also a large number of special application requirements for fast control and protection.The closing time of traditional power switch equipment is often tens of milliseconds,and the problem of insufficient fast control and protection ability is obvious.Power electronic switches with high voltage and large capacity operate quickly,but the structure and control are complicated and the cost is high.The plasma jet triggered gas gap switch with simple,reliable,low cost and strong controllability has obvious advantages.However,in order to meet the requirements of high stability in power system scenario applications,the switch equipment is required to work under extremely working coefficient,and the trigger pulse parameters are generally determined.It is difficult to quickly adjust.At present,the trigger discharge characteristics of the gas gap switch under low fixed working coefficient are not obvious.Compared with the self-breakdown gas switch,whether there is a significant difference in the insulation recovery characteristics of the plasma jet gas gap switch is a problem worthy of further discussion.Starting from the current research status of gas gap switches,this paper systematically studies the triggering discharge characteristics of plasma jet gas gap switch under extremely low working coefficient and the insulation recovery characteristics in the process of contact by means of experimental investigation and theoretical analysis,which has important scientific significance and engineering application value.The main work of the thesis and the results achieved are as follows:Firstly,the trigger discharge principle of plasma jet triggered gas gap switch is discussed in depth,and the trigger cavity structure are designed accordingly.Using the trigger circuit design of’capacitor discharge+pulse isolation boost’is adopted.the experimental research platform of gas gap switch jet plasma trigger discharge is built.Combined with the optical and electrical synchronous observation technology,the monitoring platform of jet plasma characteristic parameters is constructed.In addition,in order to explore the fast insulation recovery characteristics during the trigger discharge process of the gas gap switch,an insulation recovery process test platform based on the double pulse method was further designed and built.Secondly,under the low fixed working coefficient,the gas medium,gap distance and trigger condition parameters are systematically changed,and the gas gap switch trigger discharge characteristics test is carried out,and the voltage,current and deposition energy characteristics of the trigger cavity discharge channel in the switch trigger discharge process are further explored.The research shows that under the low fixed working coefficient,changing the content of the gas medium component,there is a significant difference between the evolution morphology of the gas gap switch jet plasma and its characteristic parameters,and the trigger conduction delay does not change significantly.Increasing the volume ratio of SF₆,the trigger conduction delay of the gas switch increases,the limit trigger working coefficient and the axial height of the jet plasma decrease,and the axial height decay rate increases.The main gap distance of the switch has a significant effect on the trigger discharge characteristics of the gas switch.With the increase of the trigger voltage,the electric power of the arc channel of the trigger cavity increases,the energy deposition efficiency of the arc channel decreases,the plasma jet height increases,the contact capacity of the gas switch increases,and the critical working coefficient and the trigger conduction delay are significantly reduced.The increase of the surface height of the trigger cavity will constrain the thermal deposition process during the development of the arc channel.The deposition energy of the arc channel increases gradually.Finally,the fast insulation recovery characteristics of the jet plasma gas gap switch during the triggered discharge process are studied,and the insulation recovery characteristics of the gas gap switch under different conditions and parameters are obtained.The experimental results show that the insulation recovery characteristics of gas gap switch experience three stages:transition period,fast recovery period and saturation period.The duration of the saturation period was much longer than the sum of the previous two stages.With the decrease of gap distance,the insulation recovery rate of gas switch increases gradually,and the basic recovery time of gap insulation can be reduced by 50%.The gas pressure has a significant effect on the insulation recovery characteristics of the gas switch,and the influence characteristics of the insulation recovery process at different stages are different.Increasing the gas pressure will slow down the insulation recovery process of the gas switch.The strong electronegative SF₆has a significant enhancement effect on the insulation recovery of gas switch,and its insulation recovery rate is close to 4 times that of dry air,which has excellent insulation recovery.更多还原