Research On Unbalanced Magnetic Tension And Vibration Characteristics Of Hydro-generator

Shaft vibration is one of the important factors that affect the stable operation of hydropower generating units,mainly affected by three aspects of hydraulic,electrical and mechanical.In the shafting structure,the additional external force on the turbine runner has sealing force,random hydraulic excitation,Draft tube pressure pulsation and unbalanced force of runner blades.The additional external force on the generator rotor includes mechanical unbalanced force and unbalanced magnetic pulling force.The unbalanced external force of the shaft system is the main factor that affects the vibration.Its accurate calculation and measurement are challenging tasks.The calculation and testing of the unbalanced magnetic tensile force have a certain theoretical basis.Based on the calculation principle and method of unbalanced magnetic tensile force,this paper focuses on the analysis of linear calculation method.First,combined with the measurement principle,a comprehensive error description model for unbalanced magnetic tensile force calculation is derived,and the quantitative analysis of the error effect of unbalanced magnetic tensile force measurement parameters is carried out;the dominant factor in balancing the measurement error of magnetic pull.Further,the modeling process of the concentrated parameter model of shafting vibration and the expression of the generator rotor swing after decoupling the stiffness of the vibration equation are introduced;combining the expression of the generator rotor swing and the balance magnetic tensile force,the theory This paper analyzes the relationship between unbalanced magnetic pulling force and generator rotor swing,and proposes a way to indirectly correct the generator air gap by using measurable swing;the hydraulic unit operation simulation system simulated in this paper and the simulation system are constructed.And gave a brief introduction and derivation of the required models.Finally,based on the hydroelectric generating unit operation simulation platform including the shaft vibration model,the simulation calculation was conducted to study the effect of unbalanced magnetic tension error on the vibration amplitude deviation of the unit,and the relationship between the generator rotor amplitude deviation and the air gap deviation was analyzed in conjunction with the simulation amplitude data;According to the derived relationship between the rotor swing and the unbalanced magnetic tension,the A value and K_M value in the formula are simulated and calculated.