基于场路耦合有限元的1250A插入式梅花触头暂态温升数值计算与分析

Numerical Calculation and Analysis of Transient Temperature Rise of 1250 A Plug-in Butt-contact Based on Field-coupled Finite Element Method

为研究电力系统不同故障电流对1250 A插入式梅花触头触点位置暂态温升特性的影响,文中采用导电桥来模拟触指与导体杆之间的表面接触,基于A-φ法建立了外电路约束下梅花触头三维电路—电磁场有限元计算模型求解触头各部位的功率损耗,将功率损耗作为载荷传递到温度场有限元模型计算获取了梅花触头的温升分布。搭建了梅花触头原型物理温升试验平台,开展物理模拟试验验证了所建立数值计算模型的有效性。基于该模型分析了短路故障电流和变压器合闸励磁涌流冲击下梅花触头触点的暂态温升特性。结果表明,触头触点瞬态温升与故障电流波形存在跟随效应。励磁涌流作用下的触点最大瞬时温升为71℃,短路电流冲击下触点最大瞬时温升达270℃。研究结果可为梅花触头的设计制造和状态检修提供参考。

In order to study the influence of different fault currents of power system on the transient temperature rise characteristics of the contact position of the butt-contact,In this paper,a conductive bridge model is used to simulate the surface contact between the fingers and the conductor bar.Based on the A-φmethod,a three-dimensional circuit-electromagnetic field finite element calculation model of the butt-contact is established.In this model,the power loss on each part of the contact is calculated with the external circuit constraints,then,the results are transmitted to the finite element model as thermal load.The temperature rise distribution of the butt-contact is obtained based on multi-physics coupling theory.Physical temperature rise test platform of the butt-contact was built,and physical experiments were carried out to verify the validity of the established numerical calculation model.The transient temperature rise characteristics of the butt-contact under the impact of short-circuit fault current and transformer excitation inrush current are analyzed by using the established field-circuit coupling numerical calculation model.The results show that the contact position reacts very quickly to the current load.The maximum instantaneous temperature rise of the contact under transformer excitation inrush current is 71℃,and the maximum instantaneous temperature rise of the contact under the impact of the short-circuit current is 270℃.The research results can provide reference for the design,manufacture and maintenance of butt-contacts.