次同步谐振下机组轴系弯扭振动信号分析

Signal Analysis on Flexural and Torsional Vibration of Generator Shafts Impacted by Subsynchronous Resonance

分析了次同步谐振下机电扭振互作用的原因。针对现场难以实现的困难,提出并设计了汽轮发电机组模拟系统的次同步谐振试验,并将HHT应用到次同步谐振下的机组弯扭振动的信号分析。Hilbert谱图定量刻画了次同步谐振下轴系弯扭振动的快速发展过程,直观准确地表现了弯扭信号的本质特征。分析表明,次同步谐振下轴系的弯振和扭振是相互影响、相互作用的,发现扭振有抑制轴系复杂频率振动的能力。当次同步谐振的扭振发生时,扭振含有的丰富频率成分发生了变化,并且弯振的二倍频消失。

A simulation experiment was designed to study subsynchronous resonance of turbo generator shafts.The Hilbert-Huang transform(HHT) was used to analyze flexural and torsional vibrations of the generator shafts impacted by subsynchronous resonance(SSR).The Hilbert spectrum quantitatively demonstrated the process of flexural and torsional vibrations and showed the essential characteristics of the vibration signals.The analysis results show that the flexural and torsional vibrations of shafts are interacted with each other,and the torsional vibration can suppress the complex shafts motions.When the torsional vibration of the subsynchronous resonance occurs,the torsional vibration frequencies change and the second frequency multiplication disappear.The Hilbert spectrum of flexural vibration can reflect the frequency variation under the impact,which is helpful to calculation of the torsional vibration duration.