Based on the summary of the research about internal short circuit faults and the main protection scheme for huge multi-branch hydro generator, the significance to research transient process in faulty condition is pointed out in the paper. By far, there almost have no perfect simulation model suits for generator optimized main protection scheme research based on internal fault transient process simulation. In this paper, the theory and validation of the simplified transient simulation model, which based on ldquodual damper bars on each polerdquo principle is proposed and explained. The simplified transient simulation model can satisfy the demands for engineering application both on calculation precision and on solving speed, so its merit for engineering practicality is demonstrated, and it provides a new approach for optimized main protection scheme research for huge hydro generator.