雷电冲击下的变电站接地网及组合电器外壳暂态特性  

Transient Characteristics of Grounding Grid and Composite Apparatus Enclosure in Substation Under Lightning Impulse

作　　者：谢雪芳[1] 熊志金[1] XIE Xuefang;XIONG Zhijin(Guangzhou Railway Polytechnic,Guangzhou,Guangdong 510430,China)

机构地区：[1]广州铁路职业技术学院,广东广州510430

出　　处：《广东电力》2021年第4期115-122,共8页Guangdong Electric Power

基　　金：广东高校科研平台项目(2020ZDZX3115)。

摘　　要：为了模拟变电站接地网及组合电器外壳在雷电冲击下的暂态特性,基于场路耦合思想,提出雷电冲击下接地网支路的π型分布参数模型和组合电器外壳的暂态模型。基于某220 kV变电站,建立组合电器外壳与接地网暂态联合仿真模型,以1.2μs/50μs雷电流作为注入波,得到组合电器外壳与接地网的暂态特性。分析结果表明:接地网边节点的暂态电位比内部节点大,接地网各节点电位的波头时间分布在2~4μs;组合电器外壳最大暂态电位出现在C相进线套管与组合电器外壳连接处;接地网电位波头时间与组合电器外壳暂态电位波头时间基本一致;接地网支路电流大小随着与雷电流注入点的距离增大呈递减趋势;接地网电流消散时间分布在200~400μs,远大于电位消散时间,离注入点越远消散时间越长。To simulate the transient characteristics of the grounding grid and the composite apparatus enclosure under lightning impulse,this paper proposes theπ-typed distributed parameter model and the transient model of the composite apparatus enclosure of the grounding grid branches under lightning impulse based on the idea of field circuit coupling.On the basis of a 220 kV substation,it establishes a transient joint simulation model,which takes 1.2/50μs lightning current as injection wave and obtains the transient characteristics of the composite apparatus and the grounding grid.The analysis results indicate that the transient potential of the side node is larger than that of the internal node,and the wave head time of each node potential is distributed within 2~4μs.The maximum transient potential appears at the junction between the C phase incoming bushing and the switchgear shell,and the potential wave head time of the grounding grid is basically consistent with the transient potential wave head time of the composite apparatus enclosure.In addition,the currents of grounding grid branches decline with increase of the distance between the branches and the location of lightning current injection point.The dissipation time of grounding grid current is 200~400μs,which is far greater than the potential dissipation time.The farther away from the injection point,the longer the dissipation time.

关 键 词：变电站接地网 雷电流 组合电器外壳 接地网支路π型模型 电位分布 电流消散 

分 类 号：TM86[电气工程—高电压与绝缘技术]