Stator temperature rise of synchronous condenser affected by temperature variation at rotor airflow outlet

The fluid and temperature distributions of the large air-cooled Synchronous Condenser (SC) are very complex, thereby the interaction of the stator and rotor airflows is often neglected in the previous study of the temperature field. In order to calculate the precise temperature rise of the SC under different operating conditions, this paper studies the effect of the temperature variation at the rotor airflow outlet on the stator temperature distribution. The loss, fluid and temperature distributions of a 300-MVar air-cooled SC are calculated based on the electromagnetic, fluid and heat transfer models. The temperature variation at the rotor airflow outlet along with the operating condition is revealed, and its effect on the stator temperature rise is analyzed. Further, it is studied that the variation laws of the stator and rotor maximum temperatures along with the air volume allocation, and the optimal air volume allocation is determined. The results can provide the reference for the accurate temperature calculation and the optimization design of the cooling systems for the large air-cooled SCs.