A High-Fidelity 3D FN-LPTN Complex Heat Transfer Model Applied to a Synchronous Condenser for Rail Transit

The synchronous condenser (SC) for rail transit is crucial for maintaining grid voltage and ensuring the stability of the traction power supply system. However, the heat generated by the parasitic magnetic flux leakage in the SC's end region limits its operational capacity, with the new dual step copper shield exacerbating heat generation. Due to the complex 3D flow paths in the end region, the cooling and heat transfer mechanisms of the copper shield and other end components remain unclear in existing studies. This paper proposes for the first time a 3D fluid network -lumped parameter thermal network (FN -LPTN) simulation to investigate the flow variation laws in the SC’s end region. A new dimensionless formula is then defined to enable rapid evaluation of the copper shield’s temperature distribution. Based on the results of the proposed model as boundary conditions, a flow-solid coupling model of the SC end region was established. The heat transfer mechanism at the end region of the SC was investigated in depth through computational fluid dynamics (CFD). Finally, the accuracy of the proposed model was verified through a temperature rise test.