Electrical transmission or interconnection systems – Plural supply circuits or sources – Substitute or emergency source
Reexamination Certificate
2001-10-02
2003-12-02
Toatley, Jr., Gregory J. (Department: 2836)
Electrical transmission or interconnection systems
Plural supply circuits or sources
Substitute or emergency source
C307S046000, C307S078000
Reexamination Certificate
active
06657321
ABSTRACT:
BACKGROUND OF INVENTION
The invention relates generally to a method and system for using turbines in direct current (DC) critical power systems.
In many critical power applications, such as in the telecommunications industry, loads require uninterruptible DC power at a fixed voltage such as −24 VDC (volts DC), −48 VDC, or −96 VDC, for example. Such critical power applications typically are set up to selectively receive power at a standard voltage and frequency from a utility grid and from a backup generator. A transfer switch is used to control whether the power is received from the utility grid or the generator. Typically such critical power applications use power from the utility grid when the utility grid is operational and from the backup generator when the utility grid is not operational. The resulting AC power is rectified to produce DC power at a regulated DC voltage. Typically, a DC energy storage system such as a battery bank with matched DC voltage is additionally connected to the load. Such storage systems are sized to meet the load requirements either until the backup generator comes on-line or for a predetermined period of time (such as a 6-8 hour ride-through capability for a plant). Such storage systems have a very large footprint. For example, a lead acid battery bank for a light industrial application requiring 200 kilowatt (kW) ride-through for 8 hours typically comprises at least 150 square feet of batteries stacked 3 feet high. Such a configuration becomes expensive in an urban environment and presents numerous maintenance and logistical issues.
It would therefore be desirable to have an uninterruptible power supply system and method which does not require large energy storage systems and which is adapted to efficiently supply regulated DC power to a load while maintaining a substantially constant predetermined DC load voltage level.
SUMMARY OF INVENTION
Briefly, in accordance with one embodiment of the present invention, a method for providing a direct current (DC) uninterruptible power supply comprises: continuously supplying fuel to a turbine; converting mechanical power from the turbine into alternating current (AC) electrical power; converting the AC electrical power to DC power within a predetermined voltage level range; supplying the DC power to a load; and maintaining a DC load voltage within the predetermined voltage level range by adjusting the amount of fuel supplied to the turbine.
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U.S. patent application, Ser. No. 09/617,954, Filed Sep. 25, 2000, Entitled A Starting System and Method for a Microturbine Power Generation Unit by G. Sinha.
U.S. patent application, Ser. No. 09/681,697, Filed May 23, 2001, Entitled “ Low-Energy Storage Fast-Start Uninterruptible Power Supply System and Method” by Robert D. King, et al.
U.S. patent application, Ser. No. 09/559,420, Filed Apr. 26, 2000, Entitled “ Distributed Electrical Power Management System for Remote Power Generators and Method of Operation”, by G. Sinha, et al.
Agosti Ann M.
General Electric Company
Patnode Patrick K.
Polk Sharon A.
Toatley , Jr. Gregory J.
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