首页|负荷不对称工况发电机定子电磁力与振动特性

负荷不对称工况发电机定子电磁力与振动特性

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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.
Electromagnetic force and vibration characteristics of generator stator under asymmetric load conditions
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 elec-tromotive forces of each sequence armature.At the same time,the magnetic electromotive forces genera-ted by the DC component of the excitation current and the even frequency AC component were consid-ered.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 de-composition,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 har-monics 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 theoreti-cal research and vibration reduction of air gap electromagnetic force in long-term operation of power gen-eration units under load asymmetry conditions.

synchronous generatorload asymmetrynegative sequence currentsymmetric component methodtwo dimensional Fourier decompositionelectromagnetic force harmonics

张广翔、武玉才、张志猛、陈聪、胡磊

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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

国网河北省电力有限公司电力科学研究院,河北 石家庄050022

中电华创(苏州)电力技术研究有限公司,江苏 苏州215123

中电华创电力技术研究有限公司,上海200086

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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

国家自然科学基金国家自然科学基金河北省自然科学基金

5227704852207053E2023502002

2024

10.15938/j.emc.2024.08.002

电机与控制学报
哈尔滨理工大学

电机与控制学报

CSTPCD北大核心
影响因子：1.014
ISSN：1007-449X
年,卷(期)：2024.28(8)