Study on the Fluid-Solid Coupling Heat Transfer in the Stator of Large Synchronous Condenser Considering Complex Transposition Structure

To solve the problem in which it is difficult to consider the complex transposition structure of the stator winding in the stator fluid-solid coupling analysis of a large synchronous condenser, a three-dimensional stator fluid-solid coupling model considering the transposition structure of the stator winding is established in this paper. Based on the heat transfer characteristics of the transposition insulation in the slot portion and involute insulation in the end portion, a non-uniform grid division method is proposed to solve the three-dimensional fluid-solid coupling model. Then, taking a 300 Mvar synchronous condenser as an example, the stator fluid distribution and temperature distribution were calculated and analyzed, and the results were compared with the non-transposition model and short-circuit type test data. The results show that the transposition structure affects the temperature distribution trend, temperature value and location of the highest temperature of the stator winding. The calculated results obtained using the transposition model were closer to the test data. Finally, the stator temperatures under no-load, over-excited, and no-excited operating conditions were calculated and compared. The results show that the stator temperature distribution trends and values are significantly affected by operating conditions. The stator temperature under the over-excited condition was the highest, and that under the no-load condition was the lowest.