Systems and methods for preventing islanding of grid-connected electrical power systems
AssigneeGeorgia Tech Research Corporation
InventorsMichael Eugene Ropp, Ajeet Rohatgi, Miroslav M. Begovic
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Abstract
A preferred embodiment of the electrical power system of the present invention includes a power conditioning unit which is configured to receive the DC electrical output signal to deliver an AC output signal to a grid-connected load. Preferably, the power conditioning unit includes a controller which is configured to monitor the AC output signal so that the power conditioning unit may cease delivering the AC output signal when a characteristic of the AC output signal satisfies an established criterion.
Claims10
A method for reducing size of a non-detection zone in a grid-connected power system having an electrical power generator with an interface to the grid, the method comprising the steps of:
- measuring frequency deviation between an output signal of the grid and an output signal of the grid-connected power system;
- applying the measured frequency deviation to the output signal of the grid-connected power system;
- and
- when the measured frequency of the output signal of the grid-connected power system satisfies an established cut-off level, discontinuing the output signal of the grid-connected power system.
A power conditioning unit for use in an electrical power system, the electrical power system being adapted to supply AC electrical power to a grid-connected load, the electrical power system being configured to convert energy into a DC electrical output signal, said power conditioning unit comprising:
- an inverter configured to receive the DC electrical output signal of the electrical power system, to convert the DC electrical output signal of the electrical power system into an AC output signal, and to deliver said AC output signal to the grid-connected load;
- a controller configured to measure the frequency deviation between an output signal of the grid and an output signal of the grid-connected power system, apply the measured frequency deviation to the output signal of the grid-connected power system, and discontinue the output signal of the grid-connected power system when the measured frequency of the output signal of the grid-connected power system satisfies an established cut-off level;
- and
- a feedback loop interconnecting said AC output signal and said controller such that said feedback loop provides said controller with information regarding said AC output signal;
- said power conditioning unit being further configured to cease delivering said AC output signal therefrom when a characteristic of said AC output signal satisfies an established criterion.
A computer readable medium having a computer program for reducing size of a non-detection zone in a grid network, the grid network having a grid-connected load and a grid-connected power system configured for supplying power thereto, the grid-connected power system having a DC electric generator and a power conditioning unit, said computer readable medium comprising:
- a first code segment configured to measure frequency deviation between an output signal of the grid and an output signal of the grid-connected power system;
- a second code segment configured to apply the measured frequency deviation to the output signal of the grid-connected power system;
- and
- a third code segment configured to discontinue output signal of the grid-connected power system at the power conditioning unit when the measured frequency of the output signal of the grid-connected power system satisfies an established cut-off level.
Dependencies are inferred from the claim text.