Controller and method

1. A method of controlling a gas turbine arranged to supply a load, the gas turbine comprising a fuel supply arranged to supply fuel at a fuel flow rate to a combustor, wherein the fuel supply comprises a first fuel supply and a second fuel supply, the method comprising:

measuring an ambient temperature and providing the fuel flow rate based, at least in part, on the measured ambient temperature,

measuring a combustion temperature,

controlling a proportion of the fuel flow rate supplied via the first fuel supply based in part on the fuel flow rate in response to the measured combustion temperature exceeding a predetermined temperature,

setting the proportion of the fuel flow rate supplied via the first fuel supply to be a constant in response to the measured combustion temperature being less than or equal to the predetermined temperature,

wherein the fuel is gaseous fuel or liquid fuel, and

wherein the proportion of the fuel flow rate supplied via the first fuel supply considers one of the following: a pressure drop in a spray of the liquid fuel and a pressure ratio of the gaseous fuel.

2. The method according to claim 1 , wherein the controlling of the proportion of the fuel flow rate supplied via the first fuel supply is based, at least in part, on a reference fuel flow rate.

3. The method according to claim 2 , wherein the reference fuel flow rate is at a first predetermined temperature, and/or a first predetermined load.

4. The method according to claim 1 , wherein the controlling of the proportion of the fuel flow rate supplied via the first fuel supply is based, at least in part, on a reference proportion of the fuel flow rate supplied via the first fuel supply.

5. The method according to claim 4 , wherein the reference proportion of the fuel flow rate supplied via the first fuel supply is at a second predetermined temperature, and/or a second predetermined load.

6. The method according to claim 4 , wherein the proportion of the fuel flow rate supplied via the first fuel supply is determined by the following equation,

P =(FFR*PR)/FF,

where P is indicative of the proportion of the fuel flow rate,

FF is indicative of the fuel flow rate,

FFR is indicative of the reference fuel flow rate, and

PR is indicative of the reference proportion of the fuel flow rate.

7. The method according to claim 5 , wherein the reference fuel flow rate is at a first predetermined temperature and/or a first predetermined load.

8. The method according to claim 1 , wherein the predetermined temperature is in a range from about 1400K to 1900K.

9. The method according to claim 1 , wherein the first fuel supply is a pilot fuel supply.

10. The method according to claim 1 , wherein the controlling of the proportion of the fuel flow rate supplied via the first fuel supply is based, at least in part, on demanded kilowatts.

11. The method according to claim 5 , wherein the gas turbine comprises a compressor, wherein the second predetermined temperature is a gas temperature at the exit of the compressor.

12. The method according to claim 3 , wherein the first predetermined temperature is the ambient temperature.

13. The method according to claim 5 , wherein the second predetermined temperature is the ambient temperature.

14. The method according to claim 3 , wherein the first predetermined temperature is 323K.

15. The method according to claim 5 , wherein the second predetermined temperature is 323K.

16. The method according to claim 8 , wherein the predetermined temperature is in a range from about 1500K to 1700K.

17. The method according to claim 8 , wherein the predetermined temperature is in a range from about 1550K to 1650K.

18. The method according to claim 3 , wherein the first predetermined load is 100%.

19. The method according to claim 2 , wherein the reference fuel flow rate is at a first predetermined temperature, and at a first predetermined load, wherein the first predetermined temperature is 323K and the first predetermined load is 100%.

20. The method according to claim 5 , wherein the second predetermined load is 100%.

21. The method according to claim 4 , wherein the reference proportion of the fuel flow rate supplied via the first fuel supply is at a second predetermined temperature, and at second predetermined load, wherein the second predetermined temperature is 323K, and the second predetermined load is 100%.

22. The method according to claim 1 , wherein the combustion temperature is a combustor exit temperature.

23. The method according to claim 1 , wherein the combustion temperature is a turbine inlet temperature.

24. A tangible non-transient computer-readable storage medium for a controller of a gas turbine arranged to supply a load, the gas turbine comprising a fuel supply arranged to supply fuel at a fuel flow rate to a combustor, wherein the fuel supply comprises a first fuel supply and a second fuel supply, the tangible non-transient computer-readable storage medium having recorded instructions thereon, which when executed by the controller, cause the controller to perform the following:

measuring an ambient temperature and providing the fuel flow rate based, at least in part, on the measured ambient temperature,

measuring a combustion temperature,

controlling a proportion of the fuel flow rate supplied via the first fuel supply based in part on the fuel flow rate in response to the measured combustion temperature exceeding a predetermined temperature,

setting the proportion of the fuel flow rate supplied via the first fuel supply to be a constant in response to the measured combustion temperature being less than or equal to the predetermined temperature,

wherein the fuel is gaseous fuel or liquid fuel, and

wherein the proportion of the fuel flow rate supplied via the first fuel supply considers one of the following: a pressure drop in a spray of the liquid fuel and a pressure ratio of the gaseous fuel.