电弧三维电磁场模型参数对GIS中VFTO的影响

Effect of Arcing Model Parameter on VFTO in GIS in 3D Electromagnetic Field Simulations

隔离开关操作产生的特快速暂态过电压(VFTO)对一次设备的绝缘和二次设备安全稳定运行产生很大的危害。电弧模型对VFTO理论分析有很大影响。基于实测电弧等效电阻,应用三维瞬态电磁场模型,分析了隔离开关操作过程中圆柱形电弧模型半径变化对VFTO分布的影响。基于矢量动态位,讨论了应用三维有限元法分析GIS内部瞬态电磁波初始条件的设定。根据实测电弧等效电阻,用导电媒质建立了用于3D电磁分析的电弧模型。对比了不同电弧模型半径下电源侧、空载母线侧和电弧处VFTO波形及峰值。通过分析发现当电弧模型的半径下降到一定数值后,半径开始对VFTO分布有较大的影响,其对电弧处电压响应幅值的影响最明显;随着电弧模型半径的减小VFTO在时间上发生滞后,电弧模型半径的减小对电源侧、负载侧和电弧处时间滞后影响程度基本相同。因此在应用3D电磁场模型分析VFTO时,电弧模型半径应尽量与实际相符。

Very fast transient overvoltage （VFTO） has much threat on insulation of primary equipment and secondary device in gas insulated substation. Arcing model is one important factor to affect simulated results of VFTOs. In this paper the effect of arcing model on distribution of VFTOs were studied based on 3D transient electromagnetic simulation model. The initial conditions for 3D transient electromagnetic simulation model were discussed based on vector dynamic potential. Comparisons of VFTOs at different positions along GIS duct were taken. From the results simulated we can see that the peak value of VFTOs at one arcing end is affected largely when the radius of arcing channel decrease to 0.03 m. And the time lags of VFTOs at the same point along duct are occurred with decrease of arcing radius. Effect of radius of arcing channel is basically the same for three different points in GIS duct. This study is beneficial to modeling for VFTO analy- sis in GIS.