水轮发电机定子电磁振动特性分析与改造研究

Analysis and modification of electromagnetic vibration in hydro-generator stator

水轮发电机定子电磁振动可能导致定子绕组绝缘磨损、定子铁心松动、电腐蚀现象加剧、拉紧螺杆疲劳断裂以及定子地脚螺栓损坏等问题,为防范这些问题导致的水轮发电机发生绝缘故障甚至严重损坏事故,本文引入单元电机概念来计算铁心振动幅值,并针对某110 MW电站#1水轮发电机定子电磁振动进行分析,提出可行的改造方案,最后通过现场检测以验证改造方案对电机定子电磁振动偏大的消除效果。结果表明,水电站#1水轮机发电机定子电磁振动主要是由反转的26次、38次定子磁势谐波与主波磁场相互作用所产生的的激振引起的,采用定子槽数为528槽的改造方案后,空载、额定负荷及100 Hz条件下的振速有效值最小值分别为0.03、0.01、0.01 mm/s,较改造前对应位置(上机架水平、下机架垂直、下机架垂直)的振速分别下降了85%、95%、43%左右,改造效果明显。本文所述方法和策略对指导水电机组开展定子电磁振动治理,保证机组长期安全稳定运行具有重要意义,同时为国内外水轮发电机定子电磁振动分析与改造提供了决策依据。

The electromagnetic vibration of hydro-generator stator may lead to stator winding insulation wear,stator core loosening,electrical corrosion,tightening screw fatigue fracture and stator anchor bolt damage.To prevent the insulation failure or even serious damage of hydro-generator caused by these problems,this paper introduces the concept of unit motor to calculate the vibration amplitude of the core,and analyzes the electromagnetic vibration of the stator of#1 hydro-generator in one 110 MW power station,and puts forward a feasible transformation scheme.Finally,the field test is used to verify the elimination effect of the transformation scheme on the electromagnetic vibration of the stator of the motor.The results show that the electromagnetic vibration of the stator of#1 turbine generator in hydropower station is mainly caused by the excitation caused by the interaction between the reversed 26th and 38th stator magnetomotive force harmonics and the main wave magnetic field.After the transformation scheme with 528 slots,the minimum effective values of vibration velocity under no-load,rated load and 100 Hz are 0.03,0.01 and 0.01 mm/s,respectively,which are 85%,95%and 43%lower than those of the corresponding positions(upper frame horizontal,lower frame vertical and lower frame vertical)before the transformation,and the transformation effect is obvious.The methods and strategies described in this paper are of great significance to guide the development of stator electromagnetic vibration control of hydropower units and ensure the long-term safe and stable operation of the units.At the same time,it provides a decision-making basis for the analysis and transformation of stator electromagnetic vibration of hydro-generators at home and abroad.