励磁绕组短路下关键运行参数差异对汽轮发电机转子动力学特性的影响

Impact of key operation parameter difference on rotor dynamic charac-teristics in turbo-generator under field winding interturn short circuit

分析了励磁绕组短路下,关键运行参数差异对汽轮发电机转子动力学特性的影响。关键运行参数包括短路程度、短路位置,以及电机负载率;转子动力学特性包括转子不平衡磁拉力激励特性、径向振动响应特性,以及转子铁芯动力学响应规律。基于柔性转子不平衡磁拉力激励与振动响应的理论分析、有限元仿真计算,以及动模试验来探索不同运行参数造成动力学特性差异的规律。结果表明:正常情况下转子不平衡磁拉力趋于零,转子振动以常规基频和定子传递过来的各偶次倍频为主;励磁绕组匝间短路下,转子不平衡磁拉力及其振动响应将产生新的奇次倍频成分,且通频振动幅值增大。随着短路程度或负载的增加,转子不平衡磁拉力与振动响应的基频将增大;短路位置越靠近大齿处,转子不平衡磁拉力与振动幅值越大;转子铁芯大齿的外表面和内槽表面边沿为动力学响应的危险位置。

This paper comprehensively analyzes the effect of key operation parameter differences on the rotor dynamic characteris⁃tics of the turbine-generator under the FISC.The key operation parameters include short degree,short position and generator load rate.The rotor’s dynamic characteristics include rotor unbalanced magnetic pull(UMP)excitation characteristics,radial vibration response characteristics and rotor core dynamics response laws.This paper explores the difference in rotor dynamic characteristics acting under different operation parameters based on the theoretical analysis of UMP excitation and vibration response of flexible ro⁃tors,finite element simulation calculation and experiment verification.It is shown that the rotor UMP closes to zero in normal con⁃ditions,and the rotor vibration is dominated by conventional fundamental frequency and the even frequency doubling transmitted by the stator.The rotor UMP and its vibration response will produce a new odd-harmonic order component,and the amplitude of pass band vibration will also be increased.As the short degree or load increases,the amplitude of the fundamental frequency of the UMP and vibration response will be increase.Besides,the closer the short position is to the big tooth,the bigger the amplitude of the UMP and vibration response will be.The most dangerous of the dynamic response positions are located at the outer surface and the inner slot surface edge of the big tooth.