燃气－蒸汽联合循环发电机组低压缸轴承振动故障分析

摘要

Large vibration occurred on bearings of low pressure cylinder of a gas-steam combined cycle generator unit.Bearing-support system simplified model was set up for vibration analysis.Support was modeled using mass and stiffness coefficients and bearing was modeled using stiffness coefficients.It is shown that bearing vibration is influenced by support stiffness largely.Shaft vibration and bearing vibration at different support stiffness cases are different.Phenomenon as large bearing vibration but with small shaft vibration is caused by lower support stiffness.A vibration example occurred on the low pressure cylinder bearings of a 390 MW combinational cycle generator unit was given and analyzed.Vibration was solved by reduction of exciting force using balance at site.It is shown that accura-cy balance is effective to reduce this kind of vibration.%某台燃气－蒸汽联合循环发电机组低压缸两侧轴承振动大。为了分析故障原因，将支撑用参振质量和刚度系数、油膜用刚度系数表示，建立了轴承支撑系统简化模型。研究结果表明，轴承振动受支撑刚度影响较大，不同支撑刚度下轴振和轴承座振动之间的差异较大，轴振小、瓦振大现象是由于支撑刚度较弱所引起的。就某台390 MW联合循环发电机组低压转子两侧轴承振动现象进行了分析，通过动平衡减小激振力的方法消除了机组振动。研究结果表明，精细动平衡是解决这类振动问题的有效手段。