A microturbine engine that includes a compressor that is operable to provide a flow of compressed air. The compressed air flows through a recuperator where it is preheated before delivery to a combustor. The preheated compressed air mixes with a fuel and is combusted within the combustor to provide a flow of products of combustion. The flow of products of combustion pass through one or more turbines to drive the compressor and a synchronous generator. The synchronous generator is able to synchronize to a priority load, to the utility grid or to both depending on the mode of operation. A control system monitors various engine parameters as well as load and grid parameters to determine the desired mode of operation.
RELATED APPLICATION DATA
This application claims benefit under 35 U.S.C. Section 119(e) of U.S. Provisional Application 60/389,765 filed Jun. 18, 2002.
The present invention relates to a method and an apparatus for controlling a power-grid connected wind turbine generator during grid faults. During grid faults, the stator windings of the wind turbine generator are disconnected from the power grid and impedances for dissipating at least part of the power generated by the wind turbine during grid fault condition are connected to the stator windings. In this way, a certain magnetisation of the generator can be maintained and after removal of the grid fault condition, the generator is synchronised to the power grid and the impedances are disconnected and the stator windings are reconnected to the power grid. In this way, it is possible to keep the wind turbine generator at least partly magnetised during grid faults and thus ready for delivering power to the power grid, as soon as the grid voltage is re-established after the fault.
A power station comprises a power-consuming shaft run on which a motor and a compressor are arranged, as well as a power-emitting shaft run on which a generator and an expansion machine are arranged. The compressor feeds a compressed fluid into a storage volume. The compressed storage fluid is expanded in the expansion machine, producing work. The generator and the motor are connected to the electrical grid system via frequency converters. This makes it possible to operate the electrical machines at a rotation speed which is asynchronous with respect to the grid system. A method and apparatus is disclosed that allows the net power output of the power station to be matched to the demands of the electrical grid system by varying the rotation speed of at least one of the shaft runs.
A method and apparatus for operating a combined-cycle power system is provided. The system is coupled to an electric power grid. The system includes at least one electric power generator, at least one steam turbine coupled to the generator, at least one combustion turbine coupled to the generator, and at least one steam source that is in flow communication with the steam turbine. The method includes operating the system at a first power output level with the steam turbine and the combustion turbine being synchronized to an operating frequency of the grid, so that the steam turbine, the combustion turbine, and the grid are operating at a frequency substantially similar to a standardized grid frequency value. The method also includes sensing a grid frequency deviation away from the standardized grid frequency value. The method further includes accelerating or decelerating the turbines and facilitating a predetermined rate of grid frequency recovery for a predetermined period of time, such that the predetermined rate of frequency recovery is substantially uniform.
A method and apparatus for operating a combined-cycle power system is provided. The system is coupled to an electric power grid. The system includes at least one electric power generator, at least one steam turbine coupled to the generator, at least one combustion turbine coupled to the generator, and at least one steam source that is in flow communication with the steam turbine. The method includes operating the system at a first power output level with the steam turbine and the combustion turbine being synchronized to an operating frequency of the grid, so that the steam turbine, the combustion turbine, and the grid are operating at a frequency substantially similar to a standardized grid frequency value. The method also includes sensing a grid frequency deviation away from the standardized grid frequency value. The method further includes accelerating or decelerating the turbines and facilitating a predetermined rate of grid frequency recovery for a predetermined period of time, such that the predetermined rate of frequency recovery is substantially uniform.
