大型核电汽轮发电机定子内部短路故障时局部电磁力分布研究

Local Electromagnetic Force Distribution Study on Giant Nuclear Turbo-Generators with Stator Short-Circuit Fault

定子绕组内部短路故障是核电汽轮发电机典型的故障之一,故障发生后极易出现转子损坏、槽楔破损、绕组断裂等严重问题。因此,掌握定子绕组内部短路故障后发电机电磁力的分布特点并找出电磁力集中位置是非常重要的。首先,建立了二维场-多回路-运动耦合时步有限元法、麦克斯韦张量法与洛伦兹力原理相结合的电磁力计算模型,然后,以一台1 407 MV·A核电汽轮发电机为例,计算了定子绕组短路故障后转子表面和定转子绕组的径向力与切向力以及定转子槽齿壁电磁力,并分析了故障后定转子的电磁力分布特点和电磁力相对集中的区域,最后讨论了计算结果的准确性与合理性。该文所研究的电磁力结果,可作为载荷应用于故障电机的结构形变分析和疲劳分析,所提出的电磁力分析思路也可为求解其他类型电机定子内部短路故障的电磁力问题提供参考。

The stator winding inter-turn short-circuit fault in nuclear power turbo-generator is one of the typical faults.It may cause rotor damage,slot wedges damage,windings fracture and some other serious problems.Therefore,it is important to know the distribution of electromagnetic force and the location in which the electromagnetic force concentration appears when the short circuit fault happens.First,a 2-D field-multi-loop circuit-motion coupled time-stepping finite element mathematical model for calculating the local electromagnetic force of giant nuclear power turbo-generator post-fault is presented,which combine the Maxwell stress and Lorentz formula.And then,a 1 407 MV·A nuclear turbo-generators is taken as an example,the radial and tangential force on rotor surface,the electromagnetic force on slot wall of stator and rotor,and the radial and tangential force on winding of stator and rotor under the giant nuclear power turbogenerator post-fault condition are calculated and analyzed.At the same time,the electromagnetic force distribution characteristics and relatively concentrated area in stator and rotor are achieved.Finally,the accuracy and rationality of calculation results are discussed.The research results of electromagnetic force in this paper can be applied to structure deformation analysis and fatigue analysis of the fault motor as a load.The proposed analysis idea for electromagnetic force can also provide a good reference for soling stator winding internal short-circuit fault,as well as other type motor.