Analysis and calculation of magnetic field and structure loss in end region of generator-motor for pumped storage power station

Generator-motor is the key equipment of pumped storage unit. The running condition changes of the unit increase the requirements of end winding motor and electromagnetic properties and raise the difficulty of design. An accurate calculation on the unit magnetic field and the end structure loss is the basis of end winding and structure design, and also is the foundation to judge whether the unit is in stable operation. Due to the difficulties in numerical analysis with complete pumped storage units power motor machine, time step finite element method (FEM) with 2D and 3D coupling, electromagnetic and movement coupling is used in this paper. A 280 MW pumped storage machine is taken as an example, and the end region magnetic field and the structural loss are calculated. First the finite element method of two dimensional motion-electromagnetic coupling is adopted. Then the motor working point is obtained combined with the operation condition of terminal iterative method, and the calculation results are compared with the measured value. Accordingly, the end model of time step finite element method with 2D and 3D coupling, electromagnetic and movement coupling is established. Taken the calculation results of 2D as the constraint conditions, the distributions of the end region magnetic field and the structure loss are calculated under rated generator condition and rated motor condition respectively. The influence of the eddy current loss with the end structural parameter change is further discussed. This paper provides a theoretical basis for pumped storage motor end winding and structure design. © 2016, The editorial office of Transaction of China Electrotechnical Society. All right reserved.