Plant control apparatus, plant control method and power plant

A plant control method for controlling a power plant, the plant comprising:

• a gas turbine;
• a generator configured to be driven by the gas turbine;
• an exhaust heat recovering boiler configured to generate first steam by using heat of exhaust gas from the gas turbine;
• a first steam turbine configured to be driven by the first steam;
• a reheater provided in the exhaust heat recovering boiler and configured to heat exhaust steam from the first steam turbine by heating the reheater from an outside of the reheater with the exhaust gas supplied to the exhaust heat recovering boiler to generate reheat steam;
• and
• a second steam turbine configured to be driven by the reheat steam;
• a clutch configured to connect a first shaft connected to the gas turbine and the generator with a second shaft connected to the first steam turbine,
• the method comprising:
• supplying second steam from equipment different from the exhaust heat recovering boiler only to the first steam turbine of both the first steam turbine and the reheater to warm up the first steam turbine, before the first steam turbine is started and before the gas turbine and the generator are started when the clutch is released;
• supplying the second steam to a reheating pipe of the reheater and heating the reheater from the outside of the reheater with the exhaust gas to warm up the reheater, before the first steam turbine is started and in a state that the gas turbine and the generator are started when the clutch is released;
• and
• directing the first steam to a bypass pipe to bypass the first turbine to supply the first steam to the reheater, wherein the bypass pipe is directly connected to the reheating pipe.

A power plant comprising:

• a gas turbine;
• a generator configured to be driven by the gas turbine;
• an exhaust heat recovering boiler configured to generate first steam by using heat of exhaust gas from the gas turbine;
• a first steam turbine configured to be driven by the first steam;
• a reheater provided in the exhaust heat recovering boiler and configured to heat exhaust steam from the first steam turbine by heating the reheater from an outside of the reheater with the exhaust gas supplied to the exhaust heat recovering boiler to generate reheat steam;
• a second steam turbine configured to be driven by the reheat steam;
• a clutch configured to connect a first shaft connected to the gas turbine and the generator with a second shaft connected to the first steam turbine;
• and
• a controller configured to:
• supply second steam from equipment different from the exhaust heat recovering boiler only to the first steam turbine of both the first steam turbine and the reheater to warm up the first steam turbine, before the first steam turbine is started and before the gas turbine and the generator are started when the clutch is released;
• supply the second steam to a reheating pipe of the reheater and heat the reheater from the outside of the reheater with the exhaust gas to warm up the reheater, before the first steam turbine is started and in a state that the gas turbine and the generator are started when the clutch is released;
• and
• direct the first steam to a bypass pipe to bypass the first turbine to supply the first steam to the reheater, wherein the bypass pipe is directly connected to the reheating pipe.