Start control unit for steam turbine plant

1. A method for controlling a start of a steam turbine plant, comprising:

inputting a measured value of a steam temperature fed to a steam turbine, a measured value or an estimated value of a rotor temperature of the steam turbine, and a measured value of a casing temperature of the steam turbine, and

controlling a steam flow rate so as to increase the steam flow rate fed to the steam turbine when a difference between the steam temperature and the rotor temperature is smaller than a first regulated value and a difference between the rotor temperature and the casing temperature is a second regulated value or larger.

2. The method of claim 1 , wherein:

the steam flow rate is controlled so as to be increased while holding the steam temperature within a predetermined range.

3. The method of claim 1 , wherein:

when the difference between the steam temperature and the rotor temperature is the first regulated value or larger and the difference between the rotor temperature and the casing temperature is the second regulated value or larger, the steam temperature and the steam flow rate are controlled so as to be held within predetermined ranges.

4. The method of claim 1 , further including:

inputting the measured value of the steam temperature fed to the steam turbine and a measured value of a rotor elongation of the steam turbine and inferring the rotor temperature.

5. A method for controlling a start of a steam turbine plant, comprising:

inputting a measured value of a steam temperature fed to a steam turbine, a measured value or an estimated value of a rotor temperature of the steam turbine, and a measured value of a casing temperature of the steam turbine;

controlling the steam temperature and a steam flow rate fed to the steam turbine so as to be held within predetermined ranges when the difference between the steam temperature and the rotor temperature is a first regulated value or larger and the difference between the rotor temperature and the casing temperature is a second regulated value or larger; and thereafter,

controlling the steam temperature and the steam flow rate so as to increase the steam flow rate fed to the steam turbine when the difference between the steam temperature and the rotor temperature becomes smaller than the first regulated value and the difference between the rotor temperature and the casing temperature is held at the second regulated value or larger, while holding the steam temperature within the predetermined range.

6. The method of claim 5 , further including:

inputting the measured value of the steam temperature fed to the steam turbine and a measured value of a rotor elongation of the steam turbine and inferring the rotor temperature.

7. A combined cycle power generation plant having:

a gas turbine, an exhaust heat recovery boiler to generate steam using exhaust heat of the gas turbine, and a steam turbine driven by the steam generated by the exhaust heat recovery boiler, wherein:

the gas turbine has a fuel flow rate adjusting valve to adjust a fuel flow rate fed to the gas turbine,

the steam turbine has a steam flow rate adjusting valve to adjust a steam flow rate fed from the exhaust heat recovery boiler, and

a start control unit is provided to input a measured value of a steam temperature fed to the steam turbine, a measured value or an estimated value of a rotor temperature of the steam turbine, and a measured value of a casing temperature of the steam turbine, and output instruction values of the fuel flow rate adjusting valve and the steam flow rate adjusting valve, wherein:

the start control unit is configured to control the fuel flow rate adjusting valve and the steam flow rate adjusting valve so as to hold the steam temperature and the steam flow rate within predetermined ranges, when a difference between the steam temperature and the rotor temperature is a first regulated value or larger and a difference between the rotor temperature and the casing temperature is a second regulated value or larger, and thereafter,

controls the steam flow rate adjusting valve so as to increase the steam flow rate while controlling the fuel flow rate adjusting valve so as to hold the steam temperature within the predetermined range, when the difference between the steam temperature and the rotor temperature becomes smaller than the first regulated value and the difference between the rotor temperature and the casing temperature is held at the second regulated value or larger.

8. A start control method for a combined cycle power generation plant having

a gas turbine, an exhaust heat recovery boiler to generate steam using exhaust heat of the gas turbine, a steam turbine driven by the steam generated by the exhaust heat recovery boiler, a fuel flow rate adjusting valve to adjust a fuel flow rate fed to the gas turbine and a steam flow rate adjusting valve to adjust a steam flow rate fed from the exhaust heat recovery boiler to the steam turbine, wherein the start control method includes:

outputting instruction values of the fuel flow rate adjusting valve and the steam flow rate adjusting valve so as to hold a steam temperature and the steam flow rate within predetermined ranges, when a difference between the steam temperature fed to the steam turbine and a rotor temperature of the steam turbine is a first regulated value or larger and a difference between the rotor temperature and a casing temperature of the steam turbine is a second regulated value or larger, and

outputting the instruction value of the steam flow rate adjusting valve so as to increase the steam flow rate while outputting the instruction value of the fuel flow rate adjusting valve so as to hold the steam temperature within the predetermined range, when the difference between the steam temperature and the rotor temperature becomes smaller than the first regulated value and the difference between the rotor temperature and the casing temperature is held at the second regulated value or larger.