A method and a system sense at least one phase difference between at least two phases of a group of parallel connected three phase AC output terminals (e.g., a first phase AC output terminal, a second phase AC output terminal, or a third phase AC output terminal). The parallel connected AC output terminals may be three parallel connected DC to AC three phase inverters. Features of the parallel connected three phase AC output terminals enable wiring of conductors to one phase of an AC output terminal to be swapped with wiring of conductors of one phase of another phase AC output terminal. A sign of at least one phase difference is verified different from signs of other phase differences thereby the system determining the lateral position of the at least one three phase inverters relative to at least one other of the three phase inverters.

A system may include a sensor having a variable phase response, a dummy impedance having a known phase response, and a measurement circuit communicatively coupled to the sensor and configured to measure first phase information associated with the sensor, measure second phase information associated with the dummy impedance, and determine a phase response of the measurement circuit based on a comparison of the first phase information to the second phase information.

A system may include a sensor having a variable phase response, a dummy impedance having a known phase response, and a measurement circuit communicatively coupled to the sensor and configured to measure first phase information associated with the sensor, measure second phase information associated with the dummy impedance, and determine a phase response of the measurement circuit based on a comparison of the first phase information to the second phase information.

A current measurement circuit includes first, second, and third conductors, a first current sensor, a second current sensor, and current computation circuitry. The first conductor is configured to conduct a first phase current of a three-phase current. The second conductor is configured to conduct a second phase current of the three-phase current. The third conductor is configured to conduct a third phase current of the three-phase current. The first current sensor is coupled to the first, the second, and the third conductors. The second current sensor is coupled to the second conductor and the third conductor. The current computation circuitry is coupled to the first current sensor and the second current sensor, and is configured to determine the first current, the second current, and the third current by applying an inverse Clarke transform to the output of the first current sensor and the output of the second current sensor.

Building automation systems, energy meters, and associated methods. A method includes receiving a plurality of voltage inputs and a plurality of current inputs from a multiphase power source. The method includes selecting a first voltage input from the plurality of voltage inputs. The method includes performing a signed power factor computation between respective pairs of the first voltage input and each of the plurality of current inputs. The method includes identifying a pair with a greatest positive power factor value. The method includes designating the identified pair with the greatest positive power factor value as an associated phase pair.

Building automation systems, energy meters, and associated methods. A method includes receiving a plurality of voltage inputs and a plurality of current inputs from a multiphase power source. The method includes selecting a first voltage input from the plurality of voltage inputs. The method includes performing a signed power factor computation between respective pairs of the first voltage input and each of the plurality of current inputs. The method includes identifying a pair with a greatest positive power factor value. The method includes designating the identified pair with the greatest positive power factor value as an associated phase pair.

A method includes performing by a processor: receiving a plurality of synchrophasor measurements of a power system signal associated with a time interval from a plurality of phasor measurement units (PMUs), respectively, each of the plurality of synchrophasor measurements including a phase angle, frequency value, and a timestamp associated with the synchrophasor measurement; determining, for each of the plurality of PMUs, a dominant mode frequency of a forced oscillation signal component of the power system signal based on the frequency value and the phase angle; determining, for each of the plurality of PMUs, a mode angle of the forced oscillation signal component at the dominant mode frequency; and determining a geographic forced oscillation source location for a source of the forced oscillation signal component based on the plurality of mode angles associated with each of the plurality of PMUs, respectively, and geographic locations of the plurality of PMUs.

A method includes performing by a processor: receiving a plurality of synchrophasor measurements of a power system signal associated with a time interval from a plurality of phasor measurement units (PMUs), respectively, each of the plurality of synchrophasor measurements including a phase angle, frequency value, and a timestamp associated with the synchrophasor measurement; determining, for each of the plurality of PMUs, a dominant mode frequency of a forced oscillation signal component of the power system signal based on the frequency value and the phase angle; determining, for each of the plurality of PMUs, a mode angle of the forced oscillation signal component at the dominant mode frequency; and determining a geographic forced oscillation source location for a source of the forced oscillation signal component based on the plurality of mode angles associated with each of the plurality of PMUs, respectively, and geographic locations of the plurality of PMUs.

System, apparatus and methods are provided for identifying a phase loss condition in a motor drive. In one example, a power conversion system includes an active rectifier, a switching inverter, and a controller. The controller is operative to generate rectifier switching control signals to operate the rectifier, measure AC input voltage signals and determine grid current signals. If the rectifier circuit is not in a switching mode, the controller identifies a suspected AC input phase loss condition if two of the AC input voltage signals are in phase with one another. If the rectifier is in the switching mode, the controller identifies a suspected AC input phase loss condition if the absolute value of the sum of two of the grid current signals is less than a predetermined non-zero threshold.

System, apparatus and methods are provided for identifying a phase loss condition in a motor drive. In one example, a power conversion system includes an active rectifier, a switching inverter, and a controller. The controller is operative to generate rectifier switching control signals to operate the rectifier, measure AC input voltage signals and determine grid current signals. If the rectifier circuit is not in a switching mode, the controller identifies a suspected AC input phase loss condition if two of the AC input voltage signals are in phase with one another. If the rectifier is in the switching mode, the controller identifies a suspected AC input phase loss condition if the absolute value of the sum of two of the grid current signals is less than a predetermined non-zero threshold.