Based on the principle of super capacitor energy storage, this paper presents a new type of electric braking device for hydraulic turbine with energy storage function, i.e. the Super Capacitor Energy Storage Brake Device (SCBD). SCBD can be used to adjust the dynamic energy of the generator rotor when the generator is under load in case of generator fault, so as to improve the stability of the hydraulic turbine transient operation, and can also be used for braking the generator rotor during the normal shutdown of the generator and assisting turbine shutdown quickly. In order to verify the SCBD function in turbine transient operation, this paper uses Differential Algebraic Multi-index Nonlinear Control (DAMNC) method to design the nonlinear coordinated control system for turbine excitation system and SCBD device. The simulation results show that the SCBD has a good electric braking effect, obviously improves the transient stability of the system, and well coordinates both the dynamic and static performance. This work is supported by National Natural Science Foundation of China (No. 51277056) and Natural Science Foundation of Guangxi Province (No. 2014GXNSFAA118338).