The hydroelectric generator is driven by a water turbine. Its rotor is short and thick, the starting time of the unit and the time required for grid connection are short, and the operation scheduling is flexible. In addition to general power generation, it is especially suitable as a peaking unit and an accident standby unit. The maximum capacity of the hydroelectric generating unit has reached 800,000 kilowatts.
The diesel Pelton Turbine Generator is driven by an internal combustion engine. It is quick to start and easy to operate, but it has high power generation cost and is mainly used as an emergency backup power source or in areas and mobile power stations that are not reached by large power grids. The capacity is between several kilowatts and several thousand kilowatts. The torque output on the shaft of the diesel engine is periodically pulsating, and it is necessary to prevent resonance and broken shaft accidents.
The speed of the hydro-generator will determine the frequency of the alternating current that is emitted. To ensure the stability of this frequency, the rotor speed must be stabilized. In order to stabilize the speed, the speed of the prime mover (Pelton Turbine) can be controlled by closed-loop control. The frequency signal of the outgoing alternating current is sampled and fed back to the control system that controls the opening and closing angle of the turbine vane to control the turbine. The output power, through the feedback control principle, can stabilize the speed of the generator.