Control of multiple fuel cell power plants at a site to provide a distributed resource in a utility grid

• US 6,757,590 B2
• Filed: 03/15/2001
• Issued: 06/29/2004
• Est. Priority Date: 03/15/2001
• Status: Expired

• Current Assignee: Hyaxiom Incorporated
• Original Assignee: UTC Fuel Cells, LLC
• Inventors: Young, Douglas Gibbons, Ross, Ricky M., Healy, Herbert C., Fragola, Francis A. Jr.
• Primary Examiner(s): Picard, Leo
• Assistant Examiner(s): ORTIZ RODRIGUEZ, CARLOS R
• Application Number:
  US09/808,762
• Publication Number:
  US 20020169523A1
• Time in Patent Office: 1,202 Days
• Field of Search: 700/22, 700/286, 307/64, 429/12, 429/19, 429/21, 429/22, 429/23, 429/92, 429/93, 429/99, 429/122, 429/123, 429/13
• US Class Current: 700/286
• CPC Class Codes: H02J 13/00002 characterised by monitoring
• CPC Class Codes: H02J 13/00016 using a wired telecommunication network or a data transmission bus
• CPC Class Codes: H02J 2300/30 The power source being a fuel cell
• CPC Class Codes: H02J 3/381 Dispersed generators
• CPC Class Codes: H02J 3/46 Controlling of the sharing of output between the generators, converters, or transformers
• CPC Class Codes: Y02E 40/70 Smart grids as climate change mitigation technology in the energy generation sector
• CPC Class Codes: Y02E 60/00 Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
• CPC Class Codes: Y04S 10/12 Monitoring or controlling equipment for energy generation units, e.g. distributed energy generation [DER] or load-side generation
• CPC Class Codes: Y04S 10/30 State monitoring, e.g. fault, temperature monitoring, insulator monitoring, corona discharge
• CPC Class Codes: Y04S 40/124 using wired telecommunication networks or data transmission busses
• CPC Class Codes: Y10S 429/90 Fuel cell including means for power conditioning, e.g. Conversion to ac

Abstract

A site management system (11) is provided for a power system (8) at site in a utility distribution grid (10). The power system (8) includes multiple fuel cell power plants (18) and one or more loads (14), for selective connection/disconnection with the grid (10) The site management system (11) controls the power plants (18) in an integrated manner, alternatively in a grid connected mode and a grid independent mode. The multiple power plants (18) at the site may be viewed and operated as a unified distributed resource on the grid (10). The site management system (11) provides signals representative of the present power capability (Kw Capacity—88) of each of the power plants (18), and a signal (Total Kw Capacity—95) representative of the total present power capability at the site. These power representations are used to appropriately assign power dispatch loadings to the respective fuel cells (18) in the grid connected mode and in the grid independent mode, and may also be used for load shedding.

Claims

1. A fuel cell-powered generating system (8) at a site for inclusion as a distributed generating resource in a distributed generation utility power grid (10), comprising:

a. multiple fuel cell power plants (18_1-n) at the site;

b. at least one electrical load (14) located substantially at the site; and

c. a site management system (11) operatively connected to each of the multiple fuel cell power plants (18_1-n), the at least one load (14), and the utility grid (10) for controlling the multiple fuel cell power plants (18_1-n) in an integrated manner, in, alternatively;

i. a grid connected mode of operation having the fuel cell power plants (18) connected to the at least one load (14) and to the power grid (10), and

ii. a grid independent mode of operation having the fuel cell power plants (18) connected to the at least one load (14) independent of connection to the power grid (10).

2. The fuel cell-powered generating system (8) of claim 1 wherein each fuel cell power plant (18) includes a fuel cell and associated sub-systems (F. C.) for generating power, a power plant controller (PPC) for controlling and monitoring the condition of the fuel cell and support sub-systems (F. C.), and a power conditioning system (PCS) for conditioning the power provided by the fuel cell to the loads, the power plant controller (PPC) further including signal processing logic (77, 79, 81, 85, 87) responsive to signals indicative of the monitored condition of the fuel cell and support sub-systems (F. C.) for providing a signal (Kw Capacity—

88) representative of the instant power output capacity of the respective fuel cell power plant (18), and wherein the site management system (11, 94) is responsive to the instant power output capacity signals (Kw capacity—

88) from each of the fuel cell power plants (18) for providing a signal (Total Kw Capacity—

95) representative of the total instant power output capacity of the multiple fuel cell power plants (18_1-n).

3. The fuel cell-powered generating system (8) of claim 2, further including a utility dispatch signal (58, 97) received from the utility, and wherein the site management system (11) includes signal processing means (96, 97, 110) responsive to the utility dispatch signal (58, 97) and the Total Kw Capacity signal (95) for selecting the lesser thereof to provide an Actual Dispatch signal (98) and for comparing the Actual Dispatch signal (98) with the Total Kw Capacity signal (95) to provide a pro-rated dispatch signal (100), and responsive to the pro-rated dispatch signal (100) and to the Kw Capacity signals (88) from each of the respective fuel cell power plants (18) to provide respective Set Power control signals (112, 90) for controlling the dispatch power for each respective fuel cell power plant (18_1-n).

4. The fuel cell-powered generating system (8) of claim 3 wherein the signal processing means (96, 97, 110) of the site management system (11) determines the mathematical product of the pro-rated dispatch signal (100) and each of the Kw Capacity signals (88) from each of the respective fuel cell power plants (18), to provide each of the respective Set Power Control signals (112, 90).

5. The fuel cell-powered generating system (8) of claim 1, further including a utility dispatch signal (58, 97) received from the utility, each fuel cell power plant (18) including a fuel cell and associated sub-systems (F. C.) for generating power, a power plant controller (PPC) for controlling and monitoring the condition of the fuel cell and support sub-systems (F. C.), and a power conditioning system (PCS) for conditioning the power provided by the fuel cells to the loads, the power plant controller (PPC) further including signal processing logic (77, 79, 81, 85, 87) responsive to the signals indicative of the monitored condition of the fuel cell and support sub-systems (F. C.) for providing a signal (Kw Capacity—

88) representative of the instant power output capacity of the respective fuel cell power plant (18), and wherein the site management system (11) includes signal processing means for dividing the utility dispatch signal (58, 97) by the multiple number of fuel cell power plants (18) to provide an initial per power plant dispatch signal value, for comparing the Kw Capacity signal (88) for an initial fuel cell power plant (18) with the per power plant dispatch signal value and assigning to that plant as much of the per power plant dispatch signal value as allowed by the respective Kw Capacity signal (88), for storing any remainder value in overflow storage, for similarly comparing and assigning to each successive one of the multiple fuel cell power plants (18) as much of the per power plant dispatch signal value as allowed by the respective Kw Capacity signal (88) and storing any respective remainder value, and for iteratively repeating the foregoing functions to allocate any remainder value remaining in the overflow storage.

6. The fuel cell-powered generating system (8) of claim 2, wherein the site management system (11) includes a power monitor (68) for providing a signal (69) representative of the total power demand of the connected loads (14_L1-LX), and further signal processing logic (34, 29) for comparing the total power demand signal (69) and the Total Kw Capacity signal (95) and, if and to the extent the total power demand exceeds the Total Kw Capacity, shedding one or more loads (14_L1-LX) in accordance with a predetermined schedule.

7. The fuel cell-powered generating system (8) of claim 6, wherein each of the multiple loads (14_L1-LX) is connected to the fuel cell power plants (18) through respective selectively controlled contactors (13_L1-LX), and wherein said shedding of one or more of the loads is effected by selectively opening respective ones of the contactors (13_L1-LX).

8. The fuel cell-powered generating system (8) of claim 1, wherein the site management system (11) is connected to receive dispatch signals from and provide status signals to, the remote utility via communications linkage (58, 62, 64, 61) connected between the site management system (11) and the utility.

9. The fuel cell-powered generating system (8) of claim 8, wherein the site management system includes a site supervisory controller (29) for effecting the integrated control of the multiple fuel cell power plants (18) and providing the control interface with the utility.

10. The fuel cell-powered generating system (8) of claim 9, wherein the site management system (11) includes a means (60) operatively connected with the site supervisory controller (29) for manually selecting operation of the generating system (8) either in a local operating mode in which the multiple power plants (18) are controlled individually or in a supervisory operating mode in which the multiple power plants (18) are operated in a unified manner.

11. The fuel cell-powered generating system (8) of claim 1, wherein the site management system (11) comprises a site supervisory controller (29) for effecting the integrated control of the multiple fuel cell power plants (18), a load shed controller (34) connected (38, 70) to interact with the site supervisory controller (29) and the loads (14, 13) to control load shedding, and a site management controller (31) connected to each of the fuel cell power plants (18) for controlling the power provided by the power plants (18) to the loads (14).

12. The fuel cell-powered generating system (8) of claim 2, wherein the site management system (11) comprises a site supervisory controller (29) for establishing, in response to a power dispatch signal from the utility, the power dispatch loading of the fuel cell power plants (18) in an integrated manner when operating in the grid connected mode, a load shed controller (34) connected (38, 70) to interact with the site supervisory controller (29) and the loads (14, 13), and a site management controller (31) connected to the PCSs of each of the respective fuel cell power plants (18) for controlling the transition of each fuel cell power plant (18) from operation in one of the grid connected and the grid independent modes, to operation in the other.

13. The fuel cell-powered generating system (8) of claim 12, wherein said site management system (11) further includes high speed, static switching means (12) connected to the utility grid (10), the fuel cell power plants (18, 15), and the loads (14, 13, 39) for rapidly disconnecting the loads (14) and the fuel cell power plants (18) from the utility grid (10) and transitioning from the grid connected mode of operation to the grid independent mode of operation.

14. The fuel cell-powered generating system (8) of claim 2, wherein initial power rating signals (Kw Rating—

76) representative of a base power capacity are provided for each of the multiple fuel cell power plants (18_1-n), and the signal processing logic (77, 79) is responsive to the monitored condition of each of the respective fuel cells and support sub-systems (F. C._1-n) to foldback the base power capacity (Kw Rating—

76) of the respective power plant (18) by an amount predetermined in accordance with the monitored condition to thereby provide the respective instant power output capacity signal value (Kw Capacity—

88).

15. A fuel cell-powered generating system (8) at a site for inclusion as a distributed generating resource in a distributed generation utility power grid (10), comprising:

a. multiple fuel cell power plants (18_1-n) at the site;

b. at least one electrical load (14) located substantially at the site;

c. a site management system (11) operatively connected to each of the multiple fuel cell power plants (18), the at least one load (14), and the utility grid (10) for controlling the multiple fuel cell power plants (18_1-n) in an integrated manner, in, alternatively;

i. a grid connected mode of operation having the fuel cell power plants (18) connected to the at least one load (14) and to the power grid (10), and

ii. a grid independent mode of operation having the fuel cell power plants (18) connected to the at least one load (14) independent of connection to the power grid (10), and wherein each fuel cell power plant (18) includes a fuel cell and associated sub-systems (F. C.) for generating power, a power plant controller (PPC) for controlling and monitoring the condition of the fuel cell and support sub-systems (F. C.), and a power conditioning system (PCS) for conditioning the power provided by the fuel cell to the loads, the power plant controller (PPC) further including signal processing logic (77, 79, 81, 85, 87) responsive to signals indicative of the monitored condition of the fuel cell and support sub-systems (F. C.) for providing a signal (Kw Capacity—

88) representative of the instant power output capacity of the respective fuel cell power plant (18).

16. The fuel cell-powered generating system (8) of claim 15, wherein said site management system (11) further includes high speed, static switching means (12) connected to the utility grid (10), the fuel cell power plants (18, 15), and the loads (14, 13, 39) for rapidly disconnecting the loads (14) and the fuel cell power plants (18) from the utility grid (10) and transitioning from the grid connected mode of operation to the grid independent mode of operation.

17. A fuel cell-powered generating system (8) at a site for inclusion as a distributed generating resource in a distributed generation utility power grid (10), comprising:

d. multiple fuel cell power plants (18_1-n) at the site;

e. at least one electrical load (14) located substantially at the site; and

f. a site management system (11) operatively connected to each of the multiple fuel cell power plants (18_1-n), the at least one load (14), and the utility grid (10) for controlling the multiple fuel cell power plants (18_1-n) in an integrated manner, in, alternatively;

i. a grid connected mode of operation having the fuel cell power plants (18) connected to the at least one load (14) and to the power grid (10), and

ii. a grid independent mode of operation having the fuel cell power plants (18) connected to the at least one load (14) independent of connection to the power grid (10),

wherein the site management system (11) further includes high speed, static switching means (12) connected to the utility grid (10), the fuel cell power plants (18, 15), and the loads (14, 13, 39) for rapidly disconnecting the loads (14) and the fuel cell power plants (18) from the utility grid (10) and transitioning from the grid connected mode of operation to the grid independent mode of operation to substantially continuously maintain power to the loads (14) from the fuel cell power plants (18).