Method and apparatus for providing economic analysis of power generation and distribution

• US 20050285574A1
• Filed: 06/25/2004
• Published: 12/29/2005
• Est. Priority Date: 06/25/2004
• Status: Active Grant

• Current Assignee: Emerson Process Management Power & Water Solutions Incorporated (Emerson Electric Company)
• Original Assignee: Emerson Process Management Power & Water Solutions Incorporated (Emerson Electric Company)
• Inventors: Huff, Frederick C., Francino, Peter N., Cheng, Xu
• Granted Patent: US 7,288,921 B2
• Time in Patent Office: Days
• US Class Current: 322/24
• CPC Class Codes: G06Q 10/04 Forecasting or optimisation specially adapted for administrative or management purposes, e.g. linear programming or "cutting stock problem" market predictions or forecasting for commercial activities G06Q30/0202
• CPC Class Codes: G06Q 10/06 Resources, workflows, human or project management; Enterprise or organisation planning; Enterprise or organisation modelling
• CPC Class Codes: G06Q 50/06 Energy or water supply
• CPC Class Codes: H02J 3/0075 for providing alternative feeding paths between load and source according to economic or energy efficiency considerations, e.g. economic dispatch
• CPC Class Codes: H02J 3/46 Controlling of the sharing of output between the generators, converters, or transformers
• CPC Class Codes: H02J 3/50 Controlling the sharing of the out-of-phase component
• CPC Class Codes: H02P 9/105 for increasing the stability
• CPC Class Codes: Y02B 70/3225 Demand response systems, e.g. load shedding, peak shaving
• CPC Class Codes: Y02E 10/72 Wind turbines with rotation axis in wind direction
• CPC Class Codes: Y04S 20/222 Demand response systems, e.g. load shedding, peak shaving

Abstract

An economic dispatch program optimally allocates load demand specifying real power and reactive power to be generated by a power plant among various power generators in a manner so that each of the power generators are operated within its optimal operating space as defined by a reactive capability curve. Allocating a power demand with consideration of the reactive capability curves of the power generators results in optimal generation of real power and reactive power as specified by the load demand. Alternatively, the economic dispatch program allocates load demand specifying real power and reactive power to be delivered by a power grid among various power plants wherein one or more of the various power plants have capacity limits exhibited by reactive capability curves.

Claims

1. A method of optimizing an operation of a power generation system having a plurality of power generation devices, the method comprising:

obtaining an objective function of the power generation system;

obtaining a plurality of operating constraints of the power generation system;

determining a plurality of relationships between a plurality of parameters of the power generation system, the plurality of relationships including a first relationship specifying an optimal operating range of one of the plurality of power generation devices as a function of a power factor of the one of the plurality of power generation devices; and

solving the plurality of relationships to obtain an optimal solution for the objective function within the plurality of operating constraints of the power generation system.

2. A method of claim 1, wherein at least one of the plurality of operating constraints specifies one of (1) a reactive power to be generated by the power generation system and (2) a real power to be generated by the power generation system.

3. A method of claim 1, wherein the first relationship is a reactive capability curve for a power generator.

4. A method of claim 3, wherein the first relationship is a reactive capability curve for one of a (1) a combustion turbo-generator and (2) a steam turbo-generator.

5. A method of claim 1, wherein the first relationship is represented by a neural-network approximation of a reactive capability curve for a generator.

6. A method of claim 1, wherein the objective function specifies a cost of operating the power generation system.

7. A method of claim 6, wherein the objective function specifies the cost of generating (1) a required amount of real power and (2) a required amount of reactive power, by a thermal power plant.

8. A method of claim 6, wherein the objective function specifies the cost of providing (1) a required amount of real power and (2) a required amount of reactive power, on a utility grid.

9. A method of claim 1, wherein the objective function specifies an emission of a first pollutant during an operation of the power generation system.

10. A method of claim 1, wherein the first relationship further specifies the optimal operating range of the one of the plurality of power generation devices in terms of at least one of (1) cold gas generator pressure within the one of the plurality of power generation devices and (2) cold gas generator temperature within the one of the plurality of power generation devices.

11. A method of claim 1, wherein the plurality of parameters of the power generation system include (1) a set of manipulated variables, (2) a set of constants and (3) a set of dependent variables.

12. A method of claim 11, wherein solving the plurality of relationships includes:

selecting a first set of values for the set of manipulated variables, wherein the first set of values represents a first candidate solution point within an operating space of the power generation system;

computing a first value of the objective function using the first set of values;

changing a value of at least one of the set of manipulated variables;

computing a second value of the objective function;

comparing the first value of the objective function and the second value of the objective function;

changing the value of the at least one of the set of manipulated variables based on the comparison of the first value of the objective function and the second value of the objective function; and

computing a first optimal solution of the objective function corresponding to the first candidate solution point.

13. A method of claim 12, wherein the first candidate solution point is selected from a plurality of candidate solution points, wherein each of the plurality of candidate solution points is used to obtain one of a plurality of candidate optimal solutions for the objective function.

14. A method of claim 13, further comprising selecting a most optimal of the plurality of candidate optimal solutions.

15. A method of claim 1, further comprising approximating the first relationship using a neural network.

16. A method of claim 15, further comprising training the neural network by operating the one of the plurality of power generation devices at a plurality of operational points specified by (1) cold gas generator pressure within the one of the plurality of power generation devices and (2) cold gas generator temperature within the one of the plurality of power generation devices, and storing the values of the real power and the reactive power generated by the one of the plurality of power generation devices.

17. A method of claim 15, further comprising updating the neural network based on one of (1) a periodic basis and (2) a predetermined criteria.

18. A method of claim 1, further comprising approximating the first relationship using a curve fitting technique.

19. A method of claim 1, further comprising receiving values of at least some of the plurality of parameters from a control system of the power generation system.

20. A method of operating a power plant having a plurality of power generators, the method comprising:

receiving a load demand specifying (1) real power to be produced by the power plant and (2) reactive power to be produced by the power plant;

determining an objective function of the power plant specifying an operating condition of the power plant as a function of (1) the real power to be produced by the power plant and (2) reactive power to be produced by the power plant; and

determining an optimal value of the objective function.

21. A method of claim 20, wherein determining the optimal value of the objective function includes ascertaining that the power plant is operated in an optimal space of a reactive capability curve of at least one of the plurality of power generators.

22. A method of claim 21, further comprising approximating the reactive capability curve using one of (1) a curve fitting technique and (2) a neural network.

23. A method of claim 22, further comprising updating the reactive capability curve based on one of (1) a periodic basis and (2) a predetermined criteria.

24. A method of claim 20, wherein determining the optimal value of the objective function comprises solving a plurality of relationships between a plurality of parameters of the power plant.

25. A method of claim 24, further comprising using an evolutionary solver for solving the plurality of relationships between the plurality of parameters of the power plant.

26. A method of claim 20, wherein the objective function specifies the cost of generating (1) the real power to be produced by the power plant and (2) reactive power to be produced by the power plant.

27. A method of claim 20, wherein the objective function specifies an emission of a first pollutant during an operation of the power plant.

28. A method of claim 20, wherein the operating condition of the power plant is one of (1) a cost and (2) an emission of a first pollutant.

29. An economic analysis system for optimizing operation of a power generation system having a plurality of power generation devices, the system comprising:

a first module adapted to store an objective function of the power generation system;

a second module adapted to store a plurality of operating constraints of the power generation system;

a third module adapted to store a plurality of relationships between a plurality of parameters of the power generation system, the plurality of relationships including a first relationship specifying an optimal operating range of one of the plurality of power generation devices as a function of a power factor of the one of the plurality of power generation devices; and

a fourth module adapted to solve the plurality of relationships to obtain an optimal solution for the objective function within the plurality of operating constraints of the power generation system.

30. An economic analysis system of claim 29, wherein the first relationship is a reactive capability curve of one a generator.

31. An economic analysis system of claim 30, wherein the third module is further adapted to approximate the reactive capability curve using one of (1) a curve fitting model and (2) a neural network model.

32. An economic analysis system of claim 31, further comprising a plant control system module communicatively connected to the third module and adapted to provide values of the plurality of parameters to the third module.

33. An economic analysis system of claim 32, further comprising a fifth module adapted to obtain updated values of at least some of the plurality of parameters and to update the reactive capability curve.

34. An economic analysis system of claim 29, wherein the fourth module is further adapted to solve the plurality of relationships using an evolutionary solver algorithm.

35. An economic analysis system of claim 29, wherein the objective function specifies a cost of operating the power generation system.

36. A method of claim 29, wherein the objective function specifies an emission of a first pollutant during an operation of the power generation system.

37. A power generation system comprising:

a plurality of power generation devices; and

an economic analysis system comprising;

a first module adapted to obtain an objective function of the power generation system,

a second module adapted to obtain a plurality of operating constraints of the power generation system,

a third module adapted to determine a plurality of relationships between a plurality of parameters of the power generation system, the plurality of relationships including a first relationship specifying an optimal operating range of one of the plurality of power generation devices as a function of a power factor of the one of the plurality of power generation devices, and

a fourth module adapted to solve the plurality of relationships to obtain an optimal solution for the objective function within the plurality of operating constraints of the power generation system.

38. A power generation system of claim 37, wherein the plurality of power generation devices include at least one of (1) a combustion turbo-generator and (2) a steam turbo-generator.

39. A power generation system of claim 37, further comprising a fifth module adapted to store values of at least some of the plurality of parameters and to approximate the first relationship based on the stored values.

40. A power generation system of claim 39, further comprising a sixth module adapted to update the approximated first relationship on a periodic basis.

41. A power generation system of claim 39, wherein the fifth module is adapted to approximate the first relationship using one of (1) a curve fitting technique and (2) a neural network.