水电机组两相线间短路时的参、强联合共振研究

为了研究水电机组在发生两相线间短路时的振动和稳定性,应用机电耦联系统的能量法,在考虑转子静偏心和振动偏心的综合影响后,得到气隙磁场能量表达式,建立轴系扭转共振时的第一阶近似微分方程.分别对参激共振、强迫共振和参、强联合共振的幅频特性进行分析,得到物理参数变化对共振影响的规律,即加大电磁阻尼、减小偏心、降低激磁电流就可以减轻振动、降低危害.研究发现,单独改变机械参数或电磁参数,都会对耦联系统的共振曲线产生明显的影响；由机电相互作用引起的系统共振现象更加丰富,这是单独的机械系统所不具备的.

Combined parametric and forced resonance of hydro-generator under short circuit between two phases

The energy method of electromechanical coupling system was applied in order to analyze vibration and stability of hydro-generator under two phases short-circuit condition.Two influencing factors,such as static eccentric and vibrating eccentric were synthetically considered,and the expression of electromagnetic field energy was obtained.The first order approximate differential equation of torsional resonance was constructed,and amplitude-frequency characteristic analysis of parametric exciting resonance,forced resonance and combined parametric and forced resonance was conducted,respectively.Results show the influencing laws of changing parameters to the resonances,namely,increasing the electromagnetic damping,reducing eccentric and lowering exciting current which can reduce vibration and harm.Only changing mechanical parameters or changing electromagnetic parameters,will significantly impact the resonance curve of the coupled electromechanical system.The electromechanical coupling action may result in more abundant resonance phenomena,which will not occur in single mechanical system.