Abstract: Along with the excitation mode transformation from the traditional, rotating AC exciter to static selfexcitation mode for large or medium hydropower and thermal power generation unit, the higher requirement was put forward for excitation transformer technique. The excitation transformer of Three Gorges Hydropower Plant was developed by using of H class insulating and Du Pont Corporation Reliatran technique. The calculation of main technical parameters and determination of structure were analyzed, and related test method of the transformer was introduced.

Key words: excitation system, Three Gorges Hydropower Plant, excitation transformer