Dependable open-phase detection in electric power delivery systems with inverter-based resources
AssigneeSchweitzer Engineering Laboratories, Inc.
InventorsBrett Mitchell Cockerham, Ritwik Chowdhury, John C. Town
Life of this patent
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Abstract
Systems and methods are described herein to detect an open-phase condition associated with an inverter-based resource for electric power generation within an electric power delivery system. An electric power delivery system may include one or more inverter-based resources that provide three phased electric power to one or more loads of an electric utility. A controller may include circuitry to measure voltage unbalances between different phases, high voltage sequences, phase voltage waveform harmonic distortions, voltage levels, and current levels to dependably detect an open-phase condition of the electric power delivery system.
Claims20
An electric power delivery system, comprising:
- an inverter based resource configured to provide three phased electric power to one or more loads;
- a breaker configured to selectively open a connection between the inverter based resource and the one or more loads;
- a first control circuit comprising:
- an unbalance voltage detection circuit configured to provide a voltage unbalance signal in response to receiving an unbalanced phase voltage signal or an unbalanced three-phase voltage sequence signal;
- a current detection circuit configured to provide a current detection signal in response to detecting a load, a low ground current and a phase current below a threshold;
- and
- a voltage detection circuit configured to provide a voltage detection signal in response to detecting a voltage higher than a threshold on all three phases of the three phased electric power;
- wherein the first control circuit is configured to provide a first break command in response to the voltage unbalance signal, the current detection signal, and the voltage detection signal;
- and
- a second control circuit comprising a waveform distortion detection circuit, wherein the waveform distortion detection circuit is configured to provide a distortion detection signal in response to determining a distortion in a voltage waveform of the three phased electric power, wherein the second control circuit is configured to provide a second break command in response to the distortion detection signal;
- wherein the breaker is configured to be opened in response to the first break command, the second break command, or both.
A controller device, comprising:
- an unbalance voltage detection circuit, wherein the unbalance voltage detection circuit is configured to provide a voltage unbalance signal in response to receiving an indication of an unbalanced phase voltage or an unbalanced three-phase voltage sequence of a three phased electric power provided on a distribution line of an electric power delivery system;
- a current detection circuit, wherein the current detection circuit is configured to provide a current detection signal in response to detecting a low phase current of the distribution line and detecting a low ground current of the distribution line;
- and
- a voltage detection circuit, wherein the voltage detection circuit is configured to provide a voltage detection signal in response to detecting a voltage higher than a threshold on at least two of the three phased electric power on the transmission line;
- wherein the controller is configured to provide a break command signal indicative of an open-phase condition of at least one of the three phases of the three phased electric power on the distribution line in response to receiving the voltage unbalance signal, the current detection signal, and the voltage detection signal.
A non-transitory computer-readable medium comprising instructions, wherein the instructions, when executed by processing circuitry, are configured to cause the processing circuitry to perform operations comprising:
- determining a distortion in a voltage waveform of a three phased electric power provided by an inverter based resource on a transmission line of an electric power delivery system;
- providing a distortion detection signal in response to determining that the distortion in the voltage waveform of at least one of the three phased electric power is above a total harmonic waveform distortion threshold;
- determining whether a breaker on the distribution line is closed;
- providing a breaker closed signal in response to determining that the breaker on the transmission line is closed;
- and
- providing a break command signal indicative of an open-phase condition of the at least one of the three phases of the three phased electric power on the distribution line in response to the distortion detection signal and the breaker closed signal.
Dependencies are inferred from the claim text.