40.5kV真空断路器分闸并联电抗器重燃过电压及抑制方法

40.5 kV真空断路器分闸并联电抗器时，极易出现截流和电弧复燃，由此产生的重燃过电压会危害系统设备绝缘，危及电网安全稳定运行。为分析重燃过电压的特性及危害，文中考虑分闸过程中真空断路器触头之间的燃弧特性，利用电磁暂态仿真软件PSCAD/EMTDC构建了准确的真空断路器的三相分闸重燃模型及开断并联电抗器的220 kV变电站系统仿真模型,分析了真空断路器分闸初相角和介质绝缘恢复速度对重燃过电压的影响。文中提出了避雷器和阻容吸收器、以及避雷器和铁氧体磁环两种过电压协同防护方案，与避雷器、阻容吸收器和铁氧体磁环单独使用时对重燃过电压的抑制效果进行了对比，并分析了不同安装位置下的抑制效果，验证了文中所提出的避雷器和阻容吸收器以及避雷器和铁氧体磁环两种协同防护重燃过电压方案的有效性。文中的研究成果为并联电抗器的投切和抑制方面的实际应用提供了理论支撑。

Reignition overvoltages caused by 40.5 kV vacuum circuit breaker switching-off shunt reactors and suppression methods

During the process of switching-off shunt reactors with vacuum circuit breakers (VCBs),reignition overvoltages (ROVs) may occur due to current chopping and arc reignition,which may damage the insulation of main power equipment and endanger the stability and safety of the power grid. In order to analyze the transient characteristics and potential hazards,in this research an accurate three-phase arc reignition model of the VCB,is developed in PSCAD/EMTDC with considering the arc characteristics of the two contacts of VCBs. Then the system simulation model of a 220 kV substation is further established. Then two factors are considered to analyze their effects on ROVs,including the opening angle and the dielectric insulation recovery velocity of VCBs. Subsequently,two types of coordinated protection schemes are proposed,including a surge arrester (SA) and a RC snubber,and a SA and a ferrite magnetic ring (FMR). Then their suppression performance is compared with that of the SA,RC snubber and FMR installed alone,and the mitigation performance of different installation positions is also investigated. Finally,the effectiveness of the proposed coordinated protection schemes for ROVs is validated. The research results of this paper can provide theoretical support for practical applications of switching-off shunt reactors and the overvoltage suppression.