基于实际气体Redlich-Kwong方程的SF6断路器开断特性  

Interruption Features in SF6 Circuit Breaker Based on Real Gas Redlich-Kwong Equation

作　　者：林莘[1] 苏安[1] 李学斌 夏亚龙 王飞鸣 LIN Xin1, SU An1, LI Xuebin2, XIA Yalong1, WANG Feiming2(1. Institute of Electrical Engineering,Shenyang University of Technology, Shenyang 110870, China; 2. Electric Power Research Institute of State Grid Liaoning Electric Power Company, Shenyang 110006, Chin)

机构地区：[1]沈阳工业大学电气工程学院,沈阳110870 [2]国网辽宁省电力有限公司电力科学研究院,沈阳110006

出　　处：《高电压技术》2018年第3期704-710,共7页High Voltage Engineering

基　　金：国家自然科学基金(51277123);国网辽宁省电力有限公司科技项目(2015YF-62)~~

摘　　要：准确的气体状态参数是计算灭弧室气流特性的关键,对SF6断路器的优化设计有重要意义。联合求解实际气体Redlich-Kwong状态方程与流场控制方程,依据Leslie S.Frost焓流电弧模型与等离子体微观参数建立非平衡态电弧能量动态模型,对40.5 kV电容器组SF_6气体断路器灭弧室进行冷态与热态气流场分析,在空载与容性小电流开断条件下,得到灭弧室内气体的压强、密度、温度分布。在开断过程中分析断路器的压力特性,通过电场与气流场的耦合计算得到弧触头间电弧熄灭后的介质恢复特性曲线。计算结果表明：Redlich-Kwong状态方程的计算误差可低至2.11%,与理想气体状态方程相比,采用Redlich-Kwong状态方程进行计算具有更高的准确度。气体流速较大时,气体状态方程对气体压强的影响较大,实际气体状态方程得到的气体压强高于理想气体。断路器开距〉7 mm后,电场强度最大值下降速度趋于平缓。断路器在开断容性小电流时,如果开断相角分别为1/10π、1/5π、3/10π、2/5π、1/2π,计算得相应燃弧时间分别为0.6、0.73、1.8、2.9、3.7 ms,存在提前熄弧现象。熄弧后断口间击穿电压始终高于瞬态恢复电压值,能够成功开断电弧不出现重燃,为获得较高的击穿裕度,开断相角应大于1/5π。Using accurate gas state parameters is the key for the calculation of flow characteristic in the arcing chamber, and it is important for optimization design of a SF6 circuit breaker. We jointly solved the real gas Redlich-Kwong equation and the flow control equation, set up a nonequilibrium energy dynamic arc model on the basis of Leslie S. Frost enthalpy flow arc model and the microscopic parameters of plasma arc, and investigated the cold and hot flow fields in the arc quenching chamber for the 40.5 kV SF_6 capacitor circuit breaker. Meanwhile, we obtained the distributions of pressure, density and temperature under the conditions of unload and capacitive small current break. Moreover,we analyzed the circuit breaker pressure characteristics in the process of opening circuit, and obtained the dielectric recovery characteristic curve between arc contact after arc extinguishing by coupling calculation of electric and flow field. The results show that the calculation error of Redlich-Kwong state equation can be as low as 2.11%. Compared with the ideal gas state equation, calculation with the Redlich-Kwong state equation has the higher accuracy. The larger the velocity is, the more the gas state equation influences the gas pressure. The gas pressure in real gas state equation is higher than that in the ideal gas. When the open distance of the circuit breaker is more than 7 mm, the decline of maximum electric field strength tends to be slow. When the circuit breaker current is small, if the open circuit phase angle is respectively 1/10π, 1/5π, 3/10π, 1/5π, 1/2π, the corresponding arc duration is 0.6 ms, 0.73 ms, 1.8 ms, 2.9 ms and 3.7 ms, which shows that the arc can be extinguished in advance. After arc extinguishing, the breakdown voltage is always higher than transient recovery voltage, so the circuit arc can be successfully cut-off. In order to obtain higher breakdown margin, the breaking phase angle should be higher than 1/5π.

关 键 词：SF6断路器 压力特性 电弧能量模型 介质恢复特性 气体状态方程 

分 类 号：TM561.3[电气工程—电器]