Hydraulic governors with its complicated structure, high initial cost and high operational cost can be eliminated for a small-sized hydraulic turbo-generator unit, which bear the base load and need for frequency regulation can be avoided. They can be replaced with motor-driven or manual, spring energy storage actuators or hydraulic actuator. If the operating power source of the actuator itself were interrupted, the actuator would automatically shut down the water turbine by means of spring energy storage and perform a two-step closing.