Methods for starting a combustion turbine and combustion turbine generator configured to implement same methods

• US 6,762,512 B2
• Filed: 05/10/2002
• Issued: 07/13/2004
• Est. Priority Date: 05/10/2002
• Status: Expired due to Term

• Current Assignee: Siemens Energy Incorporated (Siemens AG)
• Original Assignee: Westinghouse Electric Company LLC (Brookfield Asset Management Incorporated)
• Inventors: Nelson, Robert J.
• Primary Examiner(s): Waks, Joseph
• Application Number:
  US10/143,281
• Publication Number:
  US 20030209910A1
• Time in Patent Office: 795 Days
• Field of Search: 290/52, 290/40.R, 320/10
• US Class Current: 290/52
• CPC Class Codes: F01D 19/00 Starting of machines or engines; Regulating, controlling, or safety means in connection therewith warming-up before starting F01D25/10; turning or inching gear F01D25/34
• CPC Class Codes: F02C 7/268 Starting drives for the rotor , acting directly on the rotor of the gas turbine to be started
• CPC Class Codes: F02N 11/04 the motors being associated with current generators
• CPC Class Codes: F05D 2270/52 by electrical means, e.g. relays or switches

Abstract

A method for starting a combustion turbine generator 10 includes configuring the generator so that the generator'"'"'s rotor 16 is connected to receive all DC electrical power from the armature 30 of a DC-field brushless exciter 20 after rectification by a rotating rectifier. The method also includes causing the DC-field brushless exciter 20 to provide all of the DC electrical power to the rotor 16 by rotating a shaft 12 with a turning gear 22 to drive the DC-field brushless exciter 20 and rotor 16. The method further includes supplying electrical power to the generator'"'"'s stator 18 as the shaft 12 is rotating so that the stator 18 provides an accelerating torque to operate as a synchronous motor to bring the rotational speed of the shaft 12 up to a starting rotational speed. A combustion turbine generator includes a starting controller 28 to control the rotational speed of the shaft 12 and the supply of electrical power to the stator 18.

Claims

1. A method for starting a combustion turbine power generator comprising a shaft, a combustion turbine for driving the shaft when operating and having a starting rotational speed, a rotor connected to the shaft, a stator surrounding the rotor, a DC-field exciter comprising an armature and rotating rectifier connected to the shaft, a DC-field winding surrounding the armature and a turning gear for rotating the shaft, the method comprising:

configuring the combustion turbine power generator so that the rotor is connected to receive all DC electrical power from the rotating rectifier of the Dc-field exciter;

rotating the shaft with the turning gear to cause the Dc-field exciter to provide DC electrical field power to the generator rotor; and

supplying variable-frequency and variable-voltage electrical power to the stator as the shaft is rotating so that the stator cooperates with the rotor to operate as a motor to increase a rotational speed of the shaft up to the starting rotational speed of the combustion turbine;

wherein the turning gear has a nominal rotational speed and an upper rotational speed; and

wherein rotating the shaft with the turning gear comprises increasing the rotational speed of the shaft from the nominal rotational speed to the upper rotational speed;

wherein supplying electrical power to the stator is performed upon reaching the upper rotational speed from the turning gear; and

disengaging the turning gear substantially concurrently with starting to supply electrical power to the stator.

2. A method according to claim 1 wherein configuring comprises configuring the rotor to be devoid of brushes or slip rings.

3. A method according to claim 1 wherein the combustion turbine has a maximum start time;

and wherein supplying electrical power to the stator comprises supplying electrical power so that the shaft reaches the starting rotational speed before the maximum start time.

4. A method according to claim 1 wherein the DC-field exciter comprises a brushless DC-field exciter.

5. A method according to claim 1 further comprising supplying electrical power to the field of the DC-field exciter.

6. A method according to claim 1 wherein supplying electrical power to the stator comprises supplying electrical power from a static frequency converter.

7. A method for starting a combustion turbine power generator comprising a shaft, a combustion turbine for driving the shaft when operating add having a starting rotational speed, a rotor connected to the shaft, a stator surrounding the rotor, a DC-field exciter comprising an armature connected to the shaft and a field surrounding the armature so that the rotor is connected to receive all DC electrical power from the armature of the DC-field exciter, and

a turning gear for rotating the shaft between a nominal rotational speed and an upper rotational speed, the method comprising:

rotating the shaft with the turning gear to the upper rotational speed thereof to cause the DC-field exciter to provide all of the DC electrical power to the rotor upon reaching the upper rotational speed,

supplying electrical power to the stator as the shaft is rotating so that the stator cooperates with the rotor to operate as a motor to increase a rotational speed of the shaft up to the starting rotational speed of the combustion turbine; and

disengaging the turning gear after supplying electrical power to the stator.

8. A method according to claim 7 wherein the combustion turbine has a maximum start time;

and wherein supplying electrical power to the stator comprises supplying electrical power so that the shaft reaches the starting rotational speed before the maximum start time.

9. A method according to claim 7 wherein the DC-field exciter comprises a brushless DC-field exciter.

10. A method according to claim 7 further comprising supplying electrical power to the field of the DC-field exciter.

11. A method according to claim 7 wherein supplying electrical power to the stator comprises supplying electrical power to avoid an overvoltage condition of the stator.

12. A method according to claim 7 wherein supplying electrical power to the stator comprises supplying electrical power from a static frequency converter.

13. A combustion turbine power generator comprising:

a shaft;

a combustion turbine for driving said shaft when operating and having a staring rotational speed;

a rotor connected to said shaft;

a stator surrounding said rotor;

a DC-field exciter comprising an armature connected to said shaft and a field surrounding said armature, supplying a rotating rectifier, said rectifier connected to said rotor to supply all DC electrical power thereto;

a turning gear for rotating said shaft;

a stator power supply for supplying variable frequency and magnitude electrical power to said stator; and

a starting controller connected to said turning gear and said stator power supply for controlling said turning gear to rotate said shaft so that said Dc-field exciter provides all of the DC electrical power to said rotor, and

controlling said stator power supply to supply electrical power to said stator as said shaft is rotating so that said stator cooperates with said rotor to operate as a motor to increase a rotational speed of said shaft up to the starting rotational speed of said combustion turbine;

wherein the turning gear has a nominal rotational speed and an upper rotational speed; and

wherein starting controller causes the shaft to be rotated with the turning gear and the rotational speed of the shaft to be increased from the nominal rotational speed to the upper rotational speed;

wherein the stator power supply supplies electrical power to the stator upon the shaft reaching the upper rotational speed; and

wherein the turning gear disengages the shaft substantially concurrently with the stator power supply starting to supply electrical power to the stator.

14. A combustion turbine power generator according to claim 13 wherein the rotor is devoid of brushes or slip rings.

15. A combustion turbine power generator according to claim 13 wherein the combustion turbine has a maximum start time;

and wherein said starting controller causes the turning gear to rotate the shaft, and the stator power supply supplies electrical power to the stator so that the shaft reaches the starting rotational speed before the maximum start time.

16. A combustion turbine power generator according to claim 13 wherein the DC-field exciter comprises a brushless DC-field exciter.

17. A combustion turbine power generator according to claim 13 wherein the stator power supply is a static frequency converter.