Electric machines in actual operation often operate under dynamic conditions

leading to rapid internal temperature changes over time. Therefore

accurate transient heat transfer analysis is required. To address the issue of the coupled fluid-solid method

which solves the fluid field and temperature field simultaneously yielding high accuracy in temperature calculation but demands long computation time and high computational resources

the separated vector method was proposed. This method separates the fluid vector as a constant and solves only for the temperature scalar transiently

thereby reducing the computation duration and resource requirements. Taking a 300 Mvar air-cooled synchronous condenser as an example

a separated vector transient heat transfer model for its end region was established. The accuracy of the model was verified by measured temperatures. The transient heat transfer within 100 seconds after a single-phase short-circuit fault in the power transmission system was calculated. The computational processes and results of the separated vector method and the traditional coupled fluid-solid method were compared and analyzed. The results show that the computation time of the separated vector method is only 7.7% of that required by the traditional coupled fluid-solid method

and the memory required for the solution is only 64.4%. The maximum difference in the temperature calculation results between the two methods is 0.16%.