发电机内部故障下轴系受力及振动特性研究

发布时间：2018-06-19 10:47

本文选题：汽轮发电机 + 气隙静偏心　；参考：《华北电力大学》2017年硕士论文

【摘要】：气隙静偏心和转子绕组匝间短路是发电机内部常见的单因素故障,而事实上两种故障经常会同时出现耦合成多因素复合故障。本文主要对发电机内部故障下轴系电磁转矩进行理论分析和实验研究。首先通过理论推导得到不同运行状态下的电磁转矩表达式。然后利用有限元软件Ansoft建立了模拟发电机仿真模型并计算了对应的电磁转矩。最后对模拟发电机进行了实测,三者所得结果基本吻合。结果表明:正常运行下,电磁转矩不存在谐波成分,均值随着短路程度的加剧而减小。气隙静偏心使电磁转矩产生二倍频成分,偏心程度加剧时,均值与二倍频幅值增大。转子短路单故障下,发电机的电磁转矩产生一倍频成分,随着短路程度的加剧,电磁转矩均值减小,一倍频幅值增大。复合故障下,电磁转矩产生一倍频和二倍频成分。当仅短路程度加剧时,一倍频幅值增大,均值和二倍频幅值减小;当仅偏心程度加剧时,均值、一倍频和二倍频幅值增大。此外,本文对发电机内部故障下转子磁拉力进行了有限元计算与振动测试研究。结果表明:气隙静偏心单故障下转子磁拉力的主要谐波成分为直流分量与二次谐波分量,转子绕组匝间短路单故障下为一次谐波分量,复合故障下为直流分量、一次谐波分量、二次谐波分量以及三次谐波分量。其中,除直流分量外,各次谐波分量均会激励转子产生振动。论文成果为汽轮发电机实际机组存在的气隙静偏心单因素故障、转子匝间短路单因素故障及其耦合而成的多因素复合故障的监测和诊断提供了一定的参考和依据,具有积极意义。
[Abstract]:Static eccentricity of air gap and inter-turn short circuit of rotor winding are common single factor faults in generator. In this paper, the electromagnetic torque of shafting under the internal fault of generator is studied theoretically and experimentally. First, the expressions of electromagnetic torque in different operating states are derived theoretically. Then the simulation model of simulated generator is established by using finite element software Ansoft and the corresponding electromagnetic torque is calculated. Finally, the simulated generator is measured and the results are in good agreement with each other. The results show that there is no harmonic component in the electromagnetic torque under normal operation, and the mean value decreases with the increase of the short circuit degree. The static eccentricity of air gap makes the electromagnetic torque produce double frequency component. When the eccentricity intensifies, the mean value and the amplitude of double frequency increase. Under the single fault of rotor short circuit, the electromagnetic torque of generator produces one frequency doubling component. With the increase of short circuit degree, the mean value of electromagnetic torque decreases and the amplitude of double frequency increases. Under the complex fault, the electromagnetic torque produces double frequency and double frequency components. When the degree of short circuit is only increasing, the amplitude of double frequency increases, the mean and the amplitude of double frequency decrease, and when the degree of eccentricity is increased, the amplitudes of average, double frequency and double frequency increase. In addition, the finite element calculation and vibration test of rotor magnetic pull force under internal fault of generator are carried out in this paper. The results show that the main harmonic components of rotor magnetic tension are DC component and second harmonic component under air gap static eccentricity single fault, first harmonic component in rotor winding inter-turn short circuit single fault, DC component and first harmonic component in complex fault. Second harmonic component and third harmonic component. In addition to DC components, each harmonic component excites the rotor to produce vibration. The results of the paper provide a certain reference and basis for the monitoring and diagnosis of the air gap static eccentricity single factor fault, rotor interturn short circuit single factor fault and the multi-factor composite fault formed by coupling. It is of positive significance.
【学位授予单位】：华北电力大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TM31

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