负荷不对称工况发电机定子电磁力与振动特性  

Electromagnetic force and vibration characteristics of generator stator under asymmetric load conditions

作　　者：张广翔 武玉才[1] 张志猛 陈聪 胡磊 ZHANG Guangxiang;WU Yucai;ZHANG Zhimeng;CHEN Cong;HU Lei(National Key Laboratory of New Energy Power System,North China Electric Power University,Baoding 071003,China;State Grid Hebei Electric Power Research Institute,Shijiazhuang 050022,China;China Power Huachuang Electricity Technology Research Co.,Ltd.,Suzhou 215123,China;China Power Huachuang Electricity Technology Research Co.,Ltd.,Shanghai 200086,China)

机构地区：[1]华北电力大学河北省绿色高效电工新材料与设备重点实验室,河北保定071003 [2]国网河北省电力有限公司电力科学研究院,河北石家庄050022 [3]中电华创(苏州)电力技术研究有限公司,江苏苏州215123 [4]中电华创电力技术研究有限公司,上海200086

出　　处：《电机与控制学报》2024年第8期10-20,共11页Electric Machines and Control

基　　金：国家自然科学基金(52277048,52207053);河北省自然科学基金(E2023502002)。

摘　　要：为了研究电力系统中负荷不对称引起的发电机磁场畸变和振动加剧问题,针对三相不对称电流产生的负序电流,首先利用对称分量法推导出各序电枢磁动势,同时考虑励磁电流直流分量和偶倍频交流分量产生的磁动势,利用麦克斯韦应力张量法推导径向电磁力密度表达式,通过二维傅里叶分解得到电磁力密度谐波,获取电磁力密度的时间和空间谐波特征。以一台QFSN-300-2型汽轮发电机为例,仿真验证了负荷不对称工况发电机电磁力特征谐波的存在,分析得出其中两类幅值极大的新电磁力谐波为该故障下振动加剧的原因,评估了谐波对定子铁心振动和振型的影响,得出定子四倍频和六倍频振动增大的结论,对长期工作在负荷不对称状态下发电机组的气隙电磁力理论研究和振动减缓有指导意义。In order to study the problem of generator magnetic field distortion and vibration intensification caused by load asymmetry in the power system,focusing on the negative sequence current generated by three-phase asymmetric current,the symmetrical component method was used to derive the magnetic electromotive forces of each sequence armature.At the same time,the magnetic electromotive forces generated by the DC component of the excitation current and the even frequency AC component were considered.The radial electromagnetic force density expression was derived using the Maxwell stress tensor method.The electromagnetic force density harmonics were obtained through two-dimensional Fourier decomposition,and the time and space harmonic characteristics of the electromagnetic force density were obtained.Subsequently,taking a QFSN-300-2 type steam turbine generator as an example,simulation confirms the existence of electromagnetic force characteristic harmonics in the generator under asymmetric load conditions.Analysis reveals that two types of new electromagnetic force harmonics with extremely large amplitudes are the reasons for the intensification of vibration under this fault.The influence of harmonics on stator core vibration and vibration mode was evaluated,and the conclusion was drawn that the fourth and sixth harmonic vibrations of the stator increased.This has guiding significance for the theoretical research and vibration reduction of air gap electromagnetic force in long-term operation of power generation units under load asymmetry conditions.

关 键 词：同步发电机 负荷不对称 负序电流 对称分量法 二维傅里叶分解 电磁力谐波 

分 类 号：TM311[电气工程—电机]