高压SF6/N2混合气体断路器冷态介质恢复特性计算分析  

Calculation and Analysis on Cold State Dielectric Recovery Characteristics in SF6/N2 High Voltage Circuit Breakers

作　　者：林莘[1] 李璐维 李鑫涛[1] 苏安[1] 陈会利[1] LIN Xin;LI Luwei;LI Xintao;SU An;CHEN Huili(School of Electric Engineering,Shenyang University of Technology,Shenyang 110870,Liaoning Province,China)

机构地区：[1]沈阳工业大学电气工程学院

出　　处：《中国电机工程学报》2018年第15期4620-4630,共11页Proceedings of the CSEE

基　　金：国家自然科学基金重点项目(51637006);国家重点研发计划项目(2017YFB0902500);辽宁省教育厅重点实验室基础研究项目(LZ2015055)~~

摘　　要：基于N-S方程与拉氏方程对空载SF6/N2混合气体断路器灭弧室内的气流场和电场建立数学模型,计算断路器开断过程的气流特性和电场分布,分析混合比对触头间介质强度薄弱区域的气流特性影响。提出SF6/N2混合气体的击穿判据,计算不同SF6/N2混合比、开断速度及充气压力的介质恢复强度,研究断路器重击穿现象,结合SF6/N2混合气体液化温度、全球变暖潜能值,提出适用于断路器空载操作要求的SF6/N2配比方案。计算结果表明：在开断过程气流特性的作用下,介质恢复强度曲线呈现随开距增加先上升后下降,再继续升高的趋势。当灭弧室内触头间开距为14mm时,20%SF6/80%N2和80%SF6/20%N2的介质恢复强度分别是纯SF6的54.5%和91.5%;对于不同比例的SF6/N2混合气体,相同时间内开断速度9.6m/s与4.8m/s相比,介质恢复强度的增长速率明显加快;开距14mm时,60%SF6/40%N2在充气压力0.7MPa下的介质恢复强度是0.9MPa下的77.8%。考虑液化和温室效应问题,当灭弧室压力0.7MPa、开断速度9.6m/s时,SF6/N2的最佳混合比为60%：40%。Based on the N-S equation and the Laplace equation, a mathematic model of the airflow field and the electric field was established in the arc extinguish chamber of the no-load SF6/N2 mixed gas circuit breaker. The airflow characteristics and electric field distribution were calculated in the breaking process of the circuit breaker and the influence of the mixing ratio on the airflow characteristics in the weak medium region was analyzed. The breakdown criterion of SF6/N2 mixed gas was further proposed, and the dielectric recovery strength of different SF6/N2 mixing ratios, breaking speeds and inflation pressures were calculated. The phenomenon of repeated breakdown of circuit breaker was studied. Then, considering the liquefaction temperature and GWP of SF6/N2 mixed gas, the ratio scheme of SF6/N2 for the no-load operation of the circuit breaker was proposed. The results show that with the increase of the opening distance the dielectric recovery strength increases, then decreases, and then continues to increase. When the opening distance between the contact and arc contact is 14 mm, the dielectric recovery strength of 20%SF6/80%N2 and 80%SF6/20%N2 is 54.5% and 91.5% of pure SF6 respectively. For different ratios of SF6/N2 mixed gas, compared 9.6 m/s to 4.8 m/s in the same time, the growth rate of dielectric recovery strength accelerated significantly. When opening distance is 14 mm, the dielectric recovery strength of 60%SF6/40%N2 at 0.7 MPa was 77.8% to 0.9 MPa. Considering liquefaction and greenhouse effect, whenthe pressure of arc chamber is 0.7 MPa and the breaking speed is 9.6 m/s, the optimum mixing ratio of SF6/N2 is 60%：40%.

关 键 词：SF6/N2 断路器 气流场 电场 介质恢复强度 

分 类 号：TM561[电气工程—电器]