定子绕组匝间短路时转子不平衡径向磁拉力

摘要

以1台1250 MW的汽轮发电机为例,建立了该汽轮发电机的有限元分析模型.利用有限元法对该电机发生定子绕组同相同分支和同相异分支间短路进行了详细分析.分别研究了两种短路情况下,转子受到的不平衡径向电磁拉力随短路匝数(匝比)和短路点位置的变化规律.研究表明:定子绕组匝间短路情况下,径向振动的大小由不平衡径向电磁拉力决定;不平衡径向电磁拉力幅值的大小不仅受气隙磁密大小的影响,还与不同对极下气隙磁密的对称程度相关密切.%This paper analyzes a 1250 MW turbo-generator and establishes its model using finite element analysis. The short circuit faults of stator winding in single-phase single-branch and single-phase multi-branch are analyzed in detail. The changing law of unbalanced radial electromagnetic force on rotor with the number(ratio)of short turns and their lo-cations are studied under two short-circuit faults,respectively. It is shown that under the inter-turn short circuit faults of stator winding,the amplitude of radial vibration depends on the unbalanced radial electromagnetic force on rotor;the amplitude of unbalanced radial electromagnetic force on rotor depends not only on the air gap magnetic flux density ,but also on the symmetry degree of the air gap magnetic flux density of different poles.