Thermal design of external bypass for ITER poloidal field converter

The main objective of our investigation has been to survey thermal condition of equipment working in high power state work. A theoretical thermal model has been developed for the thermal design of external bypass. The junction temperature of thyristor, thermal stability and heat distributions of arms have been numerically studied. The peak junction temperature decreases with the parallel number of thyristor increases, while the parallel number is limited to the current sharing distribution. The calculated results indicate that the external bypass has excellent potential power performance and reliability. It has also been found that the temperature of stainless steel arms is highest and the bypass can work again after its first work in 390 s when all units return initial temperature. The test results show that thermal condition of the prototype is consistent with the analysis data. The research has resulted in a solution of high-power equipment.