A few questions about using the evaporative cooling method as the substitute for the water-cooling method in the three Gorges´ hydro-generator

So far as the theory, there is no problem that the evaporative cooling technology can be applied to the three Gorges´ hydro-generators. In order to validate this technology can substitute the cooling method in engineering application and get the actual operational effect, the China Three Gorges Project Corp (CTGPC) planned to make one set inner water-cooling hydro-generator installed on the left bank of the dam altered to the evaporative cooling hydro-generator. Under the precondition of not changing the main structure and maintain the primary electromagnetic design blue print, substituting the evaporative cooling method for the inner water-cooling method need to solve some key theoretic and structural problems. This paper firstly states these existing problems; through theoretic analysis and experimental research, we put forward the corresponding solving methods. Replacing the inner water-cooling method with evaporative cooling method will not only keep the advantages of inner water-cooling, but also largely improve the reliability of the hydro-generator, which will benefit to the stability of power transmission and the power supply across the grid.