水轮发电机定子磁化试验中的零节点振动问题分析与磁化试验方法探究

针对里底水电站1号机定子铁心磁化试验过程中振动及噪声过大的问题,运用有限元法对铁心零节点固有频率及三种工况下100Hz电磁激振力、铁心对应振幅进行了仿真计算。理论分析表明当铁心固有频率接近100Hz时将会产生磁化试验工况下的零节点异常振动问题,该问题不会对机组正常运行造成影响,机组投运后的实际运行结果验证了理论分析的正确性。探讨了后续机组的磁化试验方案,提出当定子铁心产生零节点异常振动时,可采用低磁密长延时常规磁化试验与ELCID相结合的替代方法,检验定子铁心的制造与叠装质量,避免共振对定子本体的损伤。

Study on Zero Node Vibration and Test Method in Magnetization Test of Hydrogenerator Stator

In view of the problem of excessive vibration and noise during the magnetization test of stator core of Unit 1 in Lidi Hydropower Station,the simulation calculation of 100Hz of electromagnetic force and corresponding amplitude of core is carried out by using finite element method.Theoretical analysis shows that when the natural frequency of the core is close to 100Hz,the problem of abnormal vibration of zero node under magnetization test condition will occur,that will not affect the normal operation of the unit.The actual operation results subsequently verify the correctness of the theoretical analysis.The magnetization test scheme of the following units is discussed.When the stator core produces abnormal vibration at zero node,by combining the conventional magnetization test with the ELCID method,the manufacturing and stacking quality of stator core can be tested to avoid the damage of resonance to the stator.