古城水电站1号机组稳定性测试与运行特性分析OA

A series of variable-speed,variable-excitation,and variable-load tests were carried out to analyze the post-maintenance operation stability of Unit 1 of Gucheng Hydropower Plant.The results are as follows:the hydroelectric generator operates in good overall state under rated conditions,and the vibration and runout amplitudes of main measuring points meet the specification requirements;the rotor mass unbalance is within the allowable range;during the variable-excitation process,the rotor exhibits significant shaft center displacement,which is primarily attributable to a fixed-direction magnetic pull force caused by misalignment between the stator and the rotor,a phenomenon directly associated with abnormal temperature differences in the shaft bearings;the variable-load test reveals a wide-amplitude vibration zone within the load range of 20%to 95%;frequency-domain analysis shows that the vibration energy is concentrated in low-frequency vortex strip components,while the rotational frequency vibration remains stable,indicating that the vibration is primarily excited by the vortex strip;furthermore,the vertical vibration of the upper frame exceeds the standard limit due to insufficient structural stiffness.It is recommended that the hydroelectric generator be operated at a high load to avoid the vibration zone,and that the monitoring of bearing runout and bearing pad temperature be strengthened.This study can provide a reference for the stability evaluation and operation optimization of similar hydroelectric generators.