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

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, e.g., fuel cells, (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 cellspower plants (18) in the grid connected mode and in the grid independent mode, and may also be used for load shedding.

Description

CROSS-REFERENCE TO RELATED APPLICATION[0001]Reference is made here to related, patent application U.S. Ser. No. 09 / 782,402, filed Feb. 13, 2001 for System for Providing Assured Power for a Critical Load by the same inventive entities as herein and owned by the same assignee as herein, now U.S. Pat. No. 6,465,910 issued Oct. 15, 2002, which application / patent is incorporated herein by reference to the extent necessary, if at all, to provide essential and / or nonessential material.TECHNICAL FIELD[0002]This invention relates generally to power systems and to the control of fuel cell power plants, and more particularly to the control of multiple fuel cell power plants at a site. More particularly still, the invention relates to the control of multiple fuel cells at a site to provide a distributed resource in a utility grid.BACKGROUND ART[0003]Individual fuel cells have been used both experimentally and commercially in various configurations to power various electrical loads. In the mai...

AI Technical Summary

Benefits of technology

[0010]Accordingly the present invention relates to a fuel cell-powered generating system at a site for inclusion as a distributed generating resource in a distributed generation utility power grid, and comprises multiple fuel cell power plants at the site, at least one, and typically multiple, loads located substantially at the site, and a site management system operatively connected to the multiple fuel cell power plants, the one or more loads, and the utility grid for controlling the fuel cell power plants in an integrated, or unified manner, in, alternatively, a grid connected mode of operation having the fuel cell power plants connected to the load(s) and to the power grid, and a grid independent mode having the fuel cell power plants connected to the load(s) independent of connection to the power grid. This integrated control provided by the site management system allows the utility to view the multiple fuel cell power plants at the site as a single, or unified, distributed generating resource when connected to the grid. Accordingly, as used in this context, the terms “integrated” and “unified” are viewed as being substantially synonymous. Moreover, the integrated control facilitates the operation of the site in the G / I mode where the fuel cells are typically load-following and have operated independently of one another. In this latter regard, the integrated control in the G / I mode further facilitates a load management (sharing and shedding) capability for assuring power to critical loads.

Problems solved by technology

However, even in such configuration, the control of the fuel cells has typically been on an individual basis, with little or no provision for an integrated control arrangement to optimize the use of multiple fuel cell power plants interconnected with the utility grid and the loads.

The transition from one such mode to the other, and the control of multiple fuel cell power plants relative to the loads present additional control complexities that have impeded the efficient and economic utilization of multiple fuel cell power plants as distributed resources in electric utility grids.

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