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

• US 7,288,921 B2
• Filed: 06/25/2004
• Issued: 10/30/2007
• 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
• Primary Examiner(s): Gonzalez; Julio
• Assistant Examiner(s): Cuevas; Pedro J.
• Application Number:
  US10/876,431
• Publication Number:
  US 20050285574A1
• Time in Patent Office: 1,222 Days
• Field of Search: 322/24, 322/20, 290/40.B, 290/40.R, 705/412, 703/3
• US Class Current: 322/20
• 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 reactive capability curves defining values of real power and reactive power generated by one of the power generation devices as a function of parameters of the device; 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 the power generation device is one of a (1) a combustion turbo-generator and (2) a steam turbo-generator.

4. A method of claim 1, wherein reaction capability curves are represented by a neural-network approximation of reactive capability curves for a generator.

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

6. A method of claim 5, 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.

7. A method of claim 5, 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.

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

9. A method of claim 1, wherein the plurality of relationships includes a relationship specifying 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.

10. 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.

11. A method of claim 10, 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.

12. A method of claim 11, 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.

13. A method of claim 12, further comprising selecting a most optimal of the plurality of candidate optimal solutions.

14. A method of claim 1, further comprising approximating the reactive capability curves using a neural network.

15. A method of claim 14, 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.

16. A method of claim 14, further comprising updating the neural network based on one of (1) a periodic basis and (2) a predetermined criteria.

17. A method of claim 1, further comprising approximating the reactive capability curves using a curve fitting technique.

18. 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.

19. 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 storing an objective function of the power generation system;

a second module storing a plurality of operating constraints of the power generation system;

a third module storing a plurality of relationships between a plurality of parameters of the power generation system, the plurality of relationships including reactive capability curves defining values of real power and reactive power generated by one of the power generation devices as a function of parameters of the device; and

a fourth module 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.

20. An economic analysis system of claim 19, wherein the third module approximates the reactive capability curves using one of(1) a curve fitting model and (2) a neural network model.

21. An economic analysis system of claim 20, further comprising a plant control system module communicatively connected to the third module with the plant control system module providing values of the plurality of parameters to the third module.

22. An economic analysis system of claim 21, further comprising a fifth module obtaining updated values of at least some of the plurality of parameters and updating the reactive capability curve.

23. An economic analysis system of claim 19, wherein the fourth module solves the plurality of relationships using an evolutionary solver algorithm.

24. An economic analysis system of claim 19, wherein the objective function specifies a cost of operating the power generation system.

25. A method of claim 19, wherein the objective function specifies an emission of a first pollutant during an operation of the power generation system.

26. A power generation system comprising:

plurality of power generation devices; and

an economic analysis system comprising;

a first module obtaining an objective function of the power generation system,

a second module obtaining a plurality of operating constraints of the power generation system,

a third module determining a plurality of relationships between a plurality of parameters of the power generation system, the plurality of relationships including reactive capability curves defining values of real power and reactive power generated by one of the power generation devices as a function of parameters of the device, and

a fourth module 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.

27. A power generation system of claim 26, wherein the plurality of power generation devices include at least one of (1) a combustion turbo-generator and (2) a steam turbo-generator.

28. A power generation system of claim 26, further comprising a fifth module storing values of at least some of the plurality of parameters and approximating the reactive capability curves based on the stored values.

29. A power generation system of claim 28, further comprising a sixth module updating the approximated first relationship on a periodic basis.

30. A power generation system of claim 28, wherein the fifth module approximates the reactive capability curves using one of (1) a curve fitting technique and (2) a neural network.