Research On Polymorphic Stress Of Turbine Generator Rotor Inter Turn Short Circuit Fault

Generator rotor inter-turn short circuit is one of the common electrical fault ofthe generator, and unbalanced electromagnetic force as well as unbalanced thermalstress are the associated Stress of this fault, which cause exceeding fundamentalvibration of the rotor. The rotor inter-turn short circuit and its fundamental vibrationare thretens to the security and stability of the power system and the national economyelectromagnetic, therefore, the research of polymorphic stress of turbine generatorrotor inter turn short circuit fault is of great importance.A QFSN220-2turbine generator was chosen for the study, the unbalancedelectromagnetic as well as thermal force of the rotor were researched based on thetheory of finite element analysis. As regards to the unbalanced electromagnetic force,a2-D simulation model of generator was established and classical electromagnetictheory was used as well to research it. The air gap magnetic field under inter turnshort, dynamic eccentricity and composite failure were analyzed. The unbalancedelectromagnetic force and it’s change law in the influence of variation of shortposition, short degree, eccentricity and angle eccentricity were researched as wellbased on the Maxwell stress method. Besides, in regard to the unbalanced thermalforce, a3-D simulation model of generator was established, and N S pole heatasymmetry which caused by short circuit was researched as well. In the basis of basicfluid mechanics theory, by using the method of the rotor coupled heat transfer, fluidfield and temperature field were calculated, the rotor temperature distribution law wasobtained as well. what’s more, the unbalanced thermal force and its variation law alsocalculated and analyzed.Through the research of this paper, the influence law of electromagnetic fielddistribution and the unbalance electromagnetic force of the rotor are obtained, and therelationship of temperature field and unbalance thermal force with short fault is alsoobtained. The results of this paper will lay a soild foundation for the comprehensivestudy of the force of generator rotor and its inter-turn short circuit rotor rotor vibrationfault diagnosis.