Anti-islanding method and apparatus for distributed power generation
AssigneePlug Power Inc.
InventorRobert H. Wills
Life of this patent
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Abstract
The invention in the simplest form is a method and apparatus for reliably protecting against island situations with one or multiple power sources connected to an electric distribution grid. The method and apparatus detects variations in the voltage and frequency of the grid. An observed change in grid voltage causes a change in output power that is sufficient to cause an even larger change in grid voltage when the utility AC power source is disconnected. An observed change in grid frequency causes a change in phase or reactive output power that is sufficient to cause an even larger change in grid frequency. If several shifts in voltage or frequency happen in the same direction, the response to the change is increased in an accelerating manner.
Claims30
A system for controlling power supplied to a utility network, comprising:
- a detector to detect a characteristic of power on a grid line of the utility network;
- an accelerator to provide an accelerating response function in response to a change in the characteristic;
- and
- circuitry to control the power supplied to the utility network based on the accelerating response function, the circuitry comprising a power converter that operates in accordance with the accelerating response function;
- wherein the circuitry controls the power supplied to the utility network so as to reduce an islanding condition of a power source relative to the utility network.
A method of controlling power supplied to a utility network, comprising;
- detecting a trend in voltage on the utility network;
- providing an accelerating response function in response to the trend;
- and
- controlling a power converter, which supplies the power to the utility network, in accordance with the accelerating response function;
- wherein controlling comprises controlling the power converter to supply power to the utility network so as to reduce an islanding condition of a power source relative to the utility network.
An apparatus for controlling power supplied to a utility network, comprising:
- circuitry to detect a trend in voltage on the utility network;
- an accelerator that provides an accelerating response function in response to the trend;
- and
- circuitry to control a power converter, which supplies the power to the utility network, in accordance with the accelerating response functions;
- wherein the circuitry to control the cower converter controls the power converter to supply power to the utility network so as to reduce an islanding condition of a power source relative to the utility network.
A system for controlling power supplied to a utility network, comprising:
- a detector to detect a characteristic of power on a grid line of the utility network and to measure a change in the characteristic, the detector comprising a voltage detector to detect voltage on the grid line;
- circuitry to control the power supplied to the utility network based on the change in the characteristic;
- a frequency detector to detect a frequency of the voltage on the grid line, the circuitry controlling the power supplied to the utility network based on outputs of both the frequency detector and the voltage detector;
- and
- a phase detector to detect a phase of the voltage on the grid line, the circuitry controlling the power supplied to the utility network based also on an output of the phase detector.
A system for controlling power supplied to a utility network, comprising:
- a detector to detect a characteristic of power on a grid line of the utility network, and to measure a change in the characteristic;
- circuitry to control the power supplied to the utility network based on the change in the characteristic;
- and
- a phase detector to detect a phase of the voltage on the grid line, the circuitry controlling the power supplied to the utility network based also on an output of the phase detector.
A system for controlling power supplied to a utility network, comprising:
- a detector to detect a characteristic of power on a grid line of the utility network;
- an accelerator to provide an accelerating response function in response to change in the characteristic;
- and
- circuitry to control the power supplied to the utility network based on the accelerating response function, the circuitry comprising a power converter that operates in accordance with the accelerating response function;
- wherein the characteristic comprises at least one of a direction and an amount of voltage change on the grid line.
Dependencies are inferred from the claim text.