A method of controlling a power generation apparatus and a pumped storage power generation apparatus, comprising:
- controlling, as a control target apparatus, a power generation apparatus or pumped storage power generation apparatus including a motor directly connected to a rotor of a generator or generator motor synchronously connected to a commercial power system, the motor being configured to drive the rotor in power generation operation and configured to be driven by the rotor in pumping operation, and
- performing, in the power generation operation, speed control by providing a guide vane opening degree command to the motor, the guide vane opening degree command being calculated, on a basis of a deviation between a rotational speed corresponding to a frequency of the commercial power system and a rotational speed of the rotor, by a rotational speed controller including a proportional control element, an integral control element, and a differential control element, wherein
- a first upper limit limiting function is multiplied by a second upper limit limiting function, the first upper limit limiting function being included in an output runaway prevention circuit of an integral control function provided in the integral control element and being defined according to an output signal of a load limiter, the second upper limit limiting function being defined according to a rotational speed deviation and changing within a range up to a constant value equal to or less than 1 according to a difference between a rotational speed corresponding to the frequency of the commercial power system and the rotational speed of the rotor,
- in a case where the rotational speed of the rotor exceeds a rotational speed corresponding to the frequency of the commercial power system, an output of a guide vane opening degree command according to an output of an accumulation in the integral control function is limited, and
- a difference between the integral control function and an output value of the runaway prevention circuit is further fed back to an input of the integral control function and is subtracted from a rotational speed deviation to forcibly decrease the accumulation in the integral control function.