Dependable open-phase detection in electric power delivery systems with inverter-based resources

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.