Research on Resistance Enhancement Coefficient and Thermal Dissipation of Stator Strands in Huge Synchronous Generator

For large generators, accurate assessment for the resistance enhancement coefficient (REC) and thermal dissipation is of great significance. With the development of design and manufacturing technology for large generators, the different cross section of the upper and lower strand becomes an effective method to reduce the heat losses. In current electromagnetism design, the eddy current analysis does not take the strand structures into account. In this paper, the REC of strands with special structures of a 150MW turbo-generator is derived by an analytic algorithm. Besides that, a mathematical model of the stator slot is established and the heat losses distribution and REC of strands are calculated by finite element method (FEM). On this basis, the stator REC and thermal dissipation of a 1000MW power turbo-generator are investigated with hollow and solid strands. The calculated results match the experimental data. All of these could provide an important theoretical basis and reference for the design of stator windings in high-power generators.