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汽轮发电机转子外伸端质量不平衡引起的振动分析 总被引:8,自引:0,他引:8
讨论了汽轮发电机转子外伸端质量不平衡产生的振动特点及其诊断方法,结合现场分析处理实例,阐明发电机转子外伸端质量不平衡产生的振动类似于主跨转子三阶不平衡引起的振动特性,但有时发电机转子两轴承处也会产生明显的反相振动分量。对于外伸端质量不平衡的识别,应根据主跨转子的振型分离情况、转子动力学知识及现场经验综合判断。 相似文献
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某发电厂7号机组为早期国产300MW机组,在发电机转子改造后,当升速、降速过发电机临界转速时,出现发电机轴瓦振动一次比一次大的现象,同时该机组低压缸轴瓦振动一直超标。对机组振动的原因为:由于发电机转子改造中装配紧力不当,在离心力作用下发电机部分部件移位或变形,导致一阶不平衡量增大,在两端加重无法将振动降到合格水平,必须在转子中部加重。通过治理,机组振动达到优良水平。 相似文献
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转子匝间短路故障对大型汽轮发电机振动的影响机理 总被引:2,自引:0,他引:2
转子匝间短路是大型汽轮发电机时常发生的电气故障,会引起励磁电流增大、输出无功减小、机组振动加剧等不良现象。因不具备分支电流互感器的安装条件,基于定子不平衡电流总有效值的故障监测原理无法应用于大型汽轮发电机,而故障引起的机组振动为监测提供了一种新思路。为此,首先从分析转子匝间短路故障时定子和转子的稳态电流特征入手,全面考虑各种空间磁场的相互作用及转子热变形等实际因素,对故障后发电机的定子和转子振动特性进行了研究;通过对故障案例的调研验证了理论分析的正确性,并分析了影响振幅的关键因素。 相似文献
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V. F. Shatokhin 《Thermal Engineering》2014,61(7):514-523
The possibility to stabilize the developing asynchronous rolling of the rotor over the stator under the conditions of power unit protections coming in action with different response times is considered. Asynchronous rolling of the rotor over the stator may develop when the rotating rotor comes in contact with the stator at high amplitudes of vibration caused by an abrupt loss of rotor balancing, by forced or self-excited vibration of the rotor, and by other factors. The danger of asynchronous rolling is connected with almost instantaneous development of self-excited vibration of the rotor when it comes in contact with the stator and with the rotor vibration amplitudes and forces of interaction between the rotor and stator dangerous for the turbine unit integrity. It is assumed that the turbine unit protection systems come in action after the arrival of signal of exceeding the permissible vibration level and produce commands to disconnect the generator from the grid, and to stop the supply of working fluid into the flow path, due to which an accelerating torque ceases to act on the turbine unit shaft. The protection system response speed is determined by a certain time t = ABtime that is taken for its components to come in action from the commencement of the event (application of the signal) to closure of the stop valves. The time curves of the main rolling parameters as functions of the ABtime value are presented. It is shown that the response time of existing protection systems is not sufficient for efficiently damping the rolling phenomenon, although the use of an electrical protection system (with the response time equal to 0.40–0.45 s) may have a positive effect on stabilizing the vibration amplitudes to a certain extent during the rolling and on smoothing its dangerous consequences. The consequences of rotor rolling over the stator can be efficiently mitigated by increasing the energy losses in the rotor-stator system (especially in the stator) and by fulfilling the recommendations of the machinery unit catastrophe prevention system. 相似文献
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该文通过有关振动试验对合山电厂6号机组的振动问题作了分析,指出其主要原因是动态匝间短路引起发电机转子热弯曲,同时低压/发电机转子联轴器的不平衡对机组振动也产生一定的影响。经处理匝间短路和实施轴系动平衡后,机组振动达到优良水平。图3表4 相似文献
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某660 MW超临界机组在试运过程中,在带负荷阶段出现发电机轴振及瓦振异常升高的故障。通过跟踪对比发电机轴瓦振动的变化,制定了试验方案并实施,在分析运行及试验数据的基础上,对发电机轴瓦振动大故障进行了诊断。诊断结果表明,发电机轴瓦振动大的原因为发电机转子线圈不对称膨胀引起热不平衡。根据诊断结果,结合现场实际运行情况,在2号低压转子和发电机的连接对轮上加配重块,进行现场高速动平衡。动平衡结果表明,发电机轴瓦振动得到了有效降低,汽轮机轴瓦振动也处在优良范围内。 相似文献
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永磁风力发电机定转子偏心会造成发电机气隙分布不均匀而产生磁场不平衡,使发电机振动加剧,严重时甚至引发转子扫膛,使发电机损坏失效。以某兆瓦级永磁风力发电机为研究对象,理论分析了气隙偏心对发电机气隙磁密和径向电磁力的影响,对于不同气隙偏心量下的风力发电机瞬态电磁场开展有限元分析,获得气隙磁密和径向电磁力分布特性变化规律,进而开展径向电磁力作用下定子谐响应分析,以掌握气隙偏心引起的定子振动响应特性。结果表明:随着气隙偏心量的增加,气隙最小处气隙磁密幅值增大,径向电磁力新增边带分量;发电机定子振动响应中工作频率的倍频幅值也随之增大,其中二阶径向模态响应幅值最大。所得结果可为发电机气隙监测方法研究提供一定的理论依据。 相似文献