水力机组系统参数全局敏感性分析

Global sensitivity analysis of hydro power generator unit system

以水力机组系统为研究对象,提出水力不平衡力解析表达式连接传统水电调节系统模型和机械子系统模型,从而构建系统的整体耦合动力学模型。采用扩展傅里叶幅度检验法(extended Fourier amplitude sensitivity test,EFAST)对复杂水电系统模型典型参数进行敏感性分析,以评估其对发电机角速度和转子质心偏移敏感特性。研究结果:(1)机组综合自调节系数、转轮进口直径、转轮出口直径、水轮机额定流量和主接力器额定位移为发电机电角速度重要敏感参数;(2)发电机转子质量偏心、水轮机转轮质量偏心、机组综合自调节系数、转轮入口直径、转轮出口直径、转轮入口直径和主接力器额定位移为发电机转子质心水平偏移敏感性参数;(3)质心主要敏感性参数与其他参数相互作用对X方向和Y方向振动摆度影响有明显区别;(4)发电机转子质心振动偏移参数敏感性强于发电机角速度值。因此,利用该模型分析具体电站振动演化时,模型调参顺序为先校准发电机角速度值,在校准心振动偏移参数。该研究为复杂水电系统模型个体化应用和模型调参提供重要科学指导依据。

Sensitivity analysis of a hydroelectric generating system is of great significance to the application and improvement of the modeling technologies.To describe the unbalanced hydraulic forces acting on the turbine blades,this paper presents analytical expressions that play a key role in linking the models of the governing system and generator units.And based on this,we develop a unified model of the hydroelectric generating system and conduct a sensitivity analysis of its 27 parameters using the extended Fourier amplitude sensitivity test(EFAST),focusing on the parameters sensitive to the angular speed and rotor centroid of the generator.Results show that 1)the generator angular speed sensitive parameters include unit self-adjustment coefficient,the penstock diameters of the runner inlet and outlet,rated flow,and rated main servomotor displacement.2)The sensitive parameters to the rotor centroid at horizontal deflection offset are the mass eccentricity of the rotor and runner,self-adjustment coefficient,the diameters of the runner outlet and outlet,and rated servomotor displacement.3)An obvious difference exists between the interaction effects of the global sensitivity parameters and other parameters on the oscillation swings in X-direction and Y-direction.4)The sensitivity to oscillation offset is stronger than that to the parameters of generator speed.Hence,when using the unified model to analyze the vibration evolution,the generator speed should be adjusted first,then the generator rotor parameters.