Research On Stator End Winding Structure Of Large Turbogenerator Based On Geometric Parameters

In the operational process of large turbogenerator stator end winding,resonance occurs due to strong electromagnetic force.It may lead to damage of structure or other serious accidents,even if stator end winding has a complex structural support.Therefore,the structural design and the analysis about the electromagnetic force of stator end winding are particularly important in both theoretical research and practical application.Firstly,the structure of the stator end winding based on the stator end winding of a 600 MW turbogenerator is introduced.Then,the solid model of stator end winding which contains all main components is established by ANSYS.Some components are omitted and reasonably equivalent by other ways in order to reduce the calculated amount.Through the calculation of the low-order modes and the homologous natural frequencies,the results are consistent with the measured results,which prove the correctness of the solid model,the connected relationship between the components and boundary conditions of the overall model.Then,the influences of the axial position and the cross-sectional area of the support ring at nose of conductor bar together with the fixed number of radial braces on the natural frequency of the stator end winding is detailed studied based on the original solid model.Based on the image method and Biot Savart law,the relationship among the axial position of conductor bar of stator end winding,time and the electromagnetic force density is deduced.The frequency spectrum of the electromagnetic force density as well as the relationship between the conductor bar and its phase current are obtained by using MATLAB software.Combined with the finite element model established before,the electromagnetic force simulation analysis of a single conductor bar is founded,which confirms the two conclusions in the mathematical model.On the one hand,there is a large torque at the nose of the conductor bar.On the other hand,the electromagnetic force mutates at the junction of the straight section and the involute section of the conductor bar.These two conclusions provide a certain reference for the binding and fixation of the conductor bar.Through the above analysis,it can be used as a reference for the structural optimization of the stator end winding of large turbogenerator and the strengthening of the protection of the weak part.