某大型水电站机组特定负荷区间厂房振动噪声成因分析与探讨

Analysis and Discussion on the Causes of Powerhouse Vibration and Noise of a Large Hydropower Station in a Specific Load Area

某大型水电站机组在低水头特定负荷区间运行时厂房出现低沉的轰鸣噪声,并伴随厂房楼板、楼梯明显振动的现象,参建各方对引起该异常现象的原因进行了逐一排查但至今尚未解决。对此进行了机组变水位稳定性和能量试验,根据试验成果对机组及厂房结构耦合振动成因进行了分析与推测,初步判断原因为固定导叶卡门涡激发了活动导叶的弯扭耦合共振,通过轴承和顶盖传导至混凝土,并导致母线层楼板及下方立柱发生共振。

Low rumbling noise accompanied by obvious vibration of the floor and stairs of powerhouse in a large hydropower station occurs in the operation at a specific low-head load range.The causes of this abnormal phenomenon are investigated by the parties involved in the construction of the station,but it has not been solved yet.In view of this problem,the variable water level stability and energy tests of the units are carried out,and according to the test results,the causes of the coupling vibration of the unit and the powerhouse structure are analyzed and speculated.The preliminary judgment is that the Karman vortex of stay vane stimulates the flexural and torsional coupling resonance of the guide vane,and then the vibration is transmitted to powerhouse concrete through the guide bearings and top cover,which leads to the resonance of the busbar floor of powerhouse and the supporting stand columns of busbar floor.