Multi-shaft variable speed gas turbine apparatus and method of controlling the same

Patent metadata

Field	Value
Publication number	US-10184406-B2
Application number	US-201415315140-A
Country	US
Kind code	B2
Filing date	Jun 18, 2014
Priority date	Jun 18, 2014
Publication date	Jan 22, 2019
Grant date	Jan 22, 2019

Abstract

A multi-shaft variable speed gas turbine apparatus includes a multi-shaft gas turbine having a gas turbine compressor, a gas turbine burner, a gas generator provided with a first turbine for rotationally driving the gas turbine compressor, and a power turbine, provided with a second turbine that is mechanically separated from the gas generator, rotationally driven by exhaust gas of the gas generator, and having a main generator. A sub-electric motor/generator is connected to the gas generator, and a frequency converter controls the sub-electric motor/generator. A fuel flow rate control valve adjusts output using a fuel flow rate to be injected into the gas turbine burner. Variation of the fuel flow rate is restricted, and a control device determines a drive load of the gas turbine compressor in accordance with an output load for a request load, and controls the sub-electric motor/generator using the frequency converter.

First claim

The invention claimed is:

1. A multi-shaft variable speed gas turbine apparatus comprising:
a multi-shaft gas turbine, the multi-shaft gas turbine including: a gas turbine compressor; a gas turbine burner; a gas generator provided with a first turbine for rotationally driving the gas turbine compressor; and a power turbine having a second turbine that is mechanically separated from the gas generator, and that is rotationally driven by an exhaust gas of the gas generator, and a main generator;
a sub-electric motor/generator connected to the gas generator;
a frequency converter that controls the sub-electric motor/generator;
a fuel flow rate control means for adjusting output by using a fuel flow rate to be injected into the gas turbine burner;
a restriction means for restricting variation of the fuel flow rate; and
a control device that determines a drive load of the gas turbine compressor in accordance with an output load, and controls the sub-electric motor/generator by using the frequency converter and a surplus energy during load rejection to be transferred to the gas turbine compressor; wherein
the control device sets a threshold for a deviation between a rotation speed of the power turbine side and an upper limit rotation speed and transfers a surplus energy corresponding to energy exceeding the threshold to the compressor side.

2. The multi-shaft variable speed gas turbine apparatus according to claim 1 , wherein
the control device determines the drive load of the gas turbine compressor by subtracting the output load from the request load.

3. The multi-shaft variable speed gas turbine apparatus according to claim 1 , comprising:
a calculation means for calculating each of the request load of the gas turbine and the drive load of the gas turbine compressor to satisfy a target load and a system frequency.

4. The multi-shaft variable speed gas turbine apparatus according to claim 1 , having a function of outputting each of a rotation speed of the gas turbine compressor and the drive load of the gas turbine compressor to a display means.

5. A multi-shaft variable speed gas turbine apparatus comprising:
a multi-shaft gas turbine, the multi-shaft gas turbine including: a gas turbine compressor; a gas turbine burner; a gas generator provided with a first turbine for rotationally driving the gas turbine compressor; and a power turbine having a second turbine that is mechanically separated from the gas generator, and that is rotationally driven by an exhaust gas of the gas generator, and a main generator;
a sub-electric motor/generator connected to the gas generator;
a frequency converter that controls the sub-electric motor/generator;
a fuel flow rate control means for adjusting output by using a fuel flow rate to be injected into the gas turbine burner;
a restriction means for restricting variation of the fuel flow rate; and
a control device that controls surplus energy during load rejection to be transferred to the gas turbine compressor; wherein
the control device sets a threshold for a deviation between a rotation speed of the power turbine side and an upper limit rotation speed and transfers a surplus energy corresponding to energy exceeding the threshold to the compressor side.

6. The multi-shaft variable speed gas turbine apparatus according to claim 5 , wherein
the control device calculates a deviation between a rotation speed on the compressor side and an upper limit rotation speed of the compressor and transfers a surplus energy corresponding to the deviation from the power turbine side.

7. A method of controlling a multi-shaft variable speed gas turbine apparatus provided with:
a multi-shaft gas turbine, the multi-shaft gas turbine including: a gas turbine compressor; a gas turbine burner; a gas generator provided with a first turbine for rotationally driving the gas turbine compressor; and a power turbine having a second turbine that is mechanically separated from the gas generator, and that is rotationally driven by an exhaust gas of the gas generator, and a main generator;
a sub-electric motor/generator connected to the gas generator; a frequency converter that controls the sub-electric motor/generator;
a fuel flow rate control means for adjusting output by using a fuel flow rate to be injected into the gas turbine burner; and
a restriction means for restricting variation of the fuel flow rate, the method comprising:
determining a drive load of the gas turbine compressor in accordance with an output load;
controlling the sub-electric motor/generator by using the frequency converter and a surplus energy during load rejection to be transferred to the gas turbine compressor; and
setting a threshold for a deviation between a rotation speed of the power turbine side and an upper limit rotation speed and transferring a surplus energy corresponding to energy exceeding the threshold to the compressor side.

8. A multi-shaft variable speed gas turbine apparatus comprising:
a multi-shaft gas turbine, the multi-shaft gas turbine including: a gas turbine compressor; a gas turbine burner; a gas generator provided with a first turbine for rotationally driving the gas turbine compressor; and a power turbine having a second turbine that is mechanically separated from the gas generator, and that is rotationally driven by an exhaust gas of the gas generator, and a main generator;
a sub-electric motor/generator connected to the gas generator;
a frequency converter that controls the sub-electric motor/generator;
a fuel flow rate control means for adjusting output by using a fuel flow rate to be injected into the gas turbine burner;
a restriction means for restricting variation of the fuel flow rate; and
a control device that controls surplus energy during load rejection to be transferred to the gas turbine compressor; wherein
the control device calculates a deviation between a rotation speed on the compressor side and an upper limit rotation speed of the compressor and transfers a surplus energy corresponding to the deviation from the power turbine side.

Assignees

• Hitachi Ltd

Inventors

• Kusumi Naohiro
• Hino Noriaki
• Thet Aung Ko

Classifications

• H02P9/04

  Control effected upon non-electric prime mover and dependent upon electric output value of the generator · CPC title

• H02K7/1823

  structurally associated with turbines or similar engines · CPC title

• F05D2260/80

  Diagnostics · CPC title

• F02C7/057

  Control or regulation (conjointly with fuel supply control F02C9/50, with nozzle area control F02K1/16) · CPC title

• H02K7/14

  Structural association with mechanical loads, e.g. with hand-held machine tools or fans (with fan or impeller for cooling the machine H02K9/06) · CPC title