Single-shaft combined cycle plant, testing method for single-shaft combined cycle plant, and control device for single-shaft combined cycle plant

A testing method for a single-shaft combined cycle plant including a generator, a gas turbine connected to the generator, a steam turbine driven by using waste heat of the gas turbine, and connected to the generator by a clutch when a rotation speed of the steam turbine is synchronized with a rotation speed of the gas turbine, a steam turbine over-rotation prevention device that stops an operation of the steam turbine, when the rotation speed of the steam turbine reaches a predetermined steam turbine upper limit rotation speed, and a gas turbine over-rotation prevention device that stops an operation of the gas turbine, when the rotation speed of the gas turbine reaches a predetermined gas turbine upper limit rotation speed, the testing method comprising:

• bringing the generator into an unloaded state;
• increasing the rotation speed of the steam turbine until the rotation speed of the steam turbine reaches the steam turbine upper limit rotation speed while maintaining the rotation speed of the gas turbine to be lower than the gas turbine upper limit rotation speed, in a state where connection between the generator and the steam turbine by the clutch is released by setting the rotation speed of the gas turbine to be higher than the rotation speed of the steam turbine;
• and
• testing whether or not the steam turbine over-rotation prevention device is in a normal operation.

A control device for a single-shaft combined cycle plant including a generator, a gas turbine connected to the generator, and a steam turbine driven by using waste heat of the gas turbine, and connected to the generator by a clutch when a rotation speed of the steam turbine is synchronized with a rotation speed of the gas turbine, the control device comprising:

• a steam turbine over-rotation prevention device that stops an operation of the steam turbine, when the rotation speed of the steam turbine reaches a predetermined steam turbine upper limit rotation speed;
• and
• a gas turbine over-rotation prevention device that stops an operation of the gas turbine, when the rotation speed of the gas turbine reaches a predetermined gas turbine upper limit rotation speed,
• wherein the control device brings the generator into an unloaded state, increases the rotation speed of the steam turbine until the rotation speed of the steam turbine reaches the steam turbine upper limit rotation speed while maintaining the rotation speed of the gas turbine to be lower than the gas turbine upper limit rotation speed, in a state where connection between the generator and the steam turbine by the clutch is released by setting the rotation speed of the gas turbine to be higher than the rotation speed of the steam turbine, and tests whether or not the steam turbine over-rotation prevention device is in a normal operation.