Analysis On Mechanics Characteristics Of Stator Windings Under Rotor Winding Interturn Short Circuit Fault In Generator

Large-capacity generators are the main force of power production,and stator windings are the key parts for energy conversion.In this paper,taking the QFSN-600-2YHG turbo-generator and MJF-30-6 type fault simulating generator as the research objects.By means of theoretical analysis,numerical simulation and experimental verification,the changing rules of the mechanical excitation properties and its response characteristics of stator windings under normal conditions,rotor interturn short-circuit(RISC)faults with different degrees and positions are revealed.Firstly,on the basis of previous theoretical deduction,according to the variation of air gap magnetic field,air gap magnetic potential and air gap magnetic density before and after RISC faults,based on Ampere force law and electromagnetic induction law,the analytical expressions of stator winding electromagnetic force before and after RISC fault are deduced respectively.Combined with rotor magnetic potential step wave change before and after faults.The variation laws of stator winding electromagnetic force under rotor windings different short-circuit degrees and positions are obtained.Then,taking QFSN-600-2YHG turbo-generator as the simulation object,the numerical simulation calculation by using the finite element simulation software Ansoft is carried out.The variation rules of the frequency components and amplitudes of the electromagnetic force on the stator winding under the rotor windings different short-circuit degrees and positions are obtained respectively.The obtained electromagnetic force density data before and after faults from Ansoft are imported into the simulation software Ansys-Workbench.And the mechanical response characteristics(total deformation,equivalent strain and equivalent stress)on the stator windings are obtained.Finally,taking MJF-30-6 fault simulation generator as the verification object,the variation laws of vibration response on the stator winding are obtained.Through theoretical analysis,numerical simulation and experimental verification comparison analysis,the three trends are basically the same.The results obtained in this paper provide a theoretical reference and basis for the analysis of insulation wear law of stator windings and the prevention of insulation damage in practical units.