Two-shaft gas turbine power generation facility, control device therefor, and control method therefor

A control method for a two-shaft gas turbine power generation facility comprising:

• a compressor which has a compressor rotor and is configured to compress air with rotation of the compressor rotor to generate compressed air;
• a combustor which is configured to combust a fuel in the compressed air to generate a combustion gas;
• a fuel adjustment valve which is configured to control a flow rate of the fuel supplied to the combustor;
• a high-pressure turbine which has a high-pressure turbine rotor mechanically connected to the compressor rotor and in which the high-pressure turbine rotor is configured to be rotated by the combustion gas;
• a low-pressure turbine which has a low-pressure turbine rotor not connected to the high-pressure turbine rotor and in which the low-pressure turbine rotor is configured to be rotated by the combustion gas exhausted from the high-pressure turbine;
• a power generator which is configured to generate electric power with rotation of the low-pressure turbine rotor and is electrically connected to a power system in which AC power flows;
• an induction motor which has a motor rotor mechanically connected to the compressor rotor and is electrically connected to the power system in parallel with the power generator to be configured to transmit and receive electric power to and from the power system;
• and
• a frequency converter which is provided between the induction motor and the power system in an electrical connection relationship to be configured to control transmission and reception of the electric power between the induction motor and the power system, is configured to convert a frequency of the electric power from the induction motor to a frequency of the power system when the electric power is transmitted from the induction motor to the power system side, and is configured to convert the frequency of the electric power from the power system to a frequency of the induction motor when the electric power is received from the power system and supplied to the induction motor,
• wherein the control method includes executing:
• a basic output calculation process of obtaining a basic output command value in accordance with a deviation between an externally required output and an actual output that is an actual output to the power system;
• a component distribution process of dividing the basic output command value into a high-frequency component and a low-frequency component;
• an opening degree command output process of obtaining an opening degree of the fuel adjustment valve on the basis of the low-frequency component of the basic output command value and outputting an opening degree command indicating the opening degree to the fuel adjustment valve;
• a basic power transmission and reception amount calculation process of obtaining a basic power transmission and reception amount of the electric power between the induction motor and the power system on the basis of the high-frequency component of the basic output command value;
• and
• a power transmission and reception command output process of creating a power transmission and reception command indicating a power transmission and reception amount of the electric power between the induction motor and the power system in accordance with the basic power transmission and reception amount and outputting the power transmission and reception command to the frequency converter.