超B类感应电流快速释放装置冷态介质恢复特性计算及分析

Calculations and Analysis on Cold State Dielectric Recovery Characteristic in Super Class B Induced Current High Speed Release Device

针对超B类感应电流快速释放装置开断过程冷态介质恢复特性进行数值计算及分析。计算开断过程中气室内电场强度和SF6介质密度,依据流注理论,得到触头间临界击穿电压曲线,通过介质临界击穿电压与瞬态恢复电压(TRV)的对比,验证是否满足该快速释放装置冷态开断能力的要求。计算结果表明:动触头到达分闸点之后,气室内SF6介质密度基本保持不变,维持在27 kg/m3左右,而场强随开距的变化较明显,因此,电恢复过程是影响介质恢复特性的主要因素;超B类感应电流快速释放装置在冷态开断过程中,开距小于25 mm时临界击穿电压值小于TRV值,说明在此开距范围内,重击穿的可能性极大。

The dielectric recovery characteristics on cohl state during interrupting course of super class B induced current high speed release device are studied by numerical calculations and analyses. The dynamie changes of electric field intensity and the density of SF6 in gas chamber during interrupting course are calculated. Critical breakdown voltage curve could be obtained based on the stream theory. By comparing the critical breakdown voltage and the transient recovery voltage（TRV）, to verify whether it meets the requirements of the cold state breaking ability of the high speed release device. The results show that： the density of SF6 in gas chamber is.basically unchanged, which remains at about 27 kg/m3, while the electric field intensity is obviously changed with opening range. Therefore, the dielectric strength recovery process is the main factor affecting the dielectric recovery characteristics. When super class B induced current high speed release device in the cold state breaking process, the critical breakdown voltage is less than the TRV value with the opening range less than 25 mm, indicating that when the opening distance is in this range, the possibility of restrike is very great.