A method of detecting phase loss of a three-phase AC power source includes steps of: acquiring any two line voltages of the AC power source with a first cycle period, acquiring a first digital signal and a second digital signal, performing an exclusive OR operation between the first digital signal and the second digital signal to generate a level signal, accumulating a high-level time count value, or accumulating a low-level time count value, resetting the low-level time count value when the high-level time count value is accumulated, or resetting the high-level time count value when the low-level time count value is accumulated, and determining that the AC power source occurs a phase-loss abnormality when the high-level time count value is greater than or equal to ⅓ of the first cycle period or the low-level time count value is greater than or equal to ⅙ of the first cycle period.

SOGI based apparatus and methods for providing balanced three phase output signals free of harmonics, DC components and imbalance present in the input signals, are disclosed. In addition, such apparatus and methods for providing corresponding output signals which are drift-free integrals of the input signals and which signals may enable the control of a power electronics inverter for improved and robust grid power injection and for motor control are disclosed.

A fault detection system has line current monitors. Each line current monitor couples to a line-phase of an electric power transmission system. Each line current monitor has a phase detector, a loop filter and a controlled oscillator, coupled as a phase locked loop. The phase detector has a rotating frame transform. The phase detector couples to a line-phase and provides in-phase and quadrature signals in a rotating frame, based on in-phase and quadrature signals proportional to current in the line-phase. One or more fault detection modules are coupled to the line current monitors through inter-phase communication of the in-phase and quadrature signals in a time frame rotating at the line frequency. The communication may have electrical isolation.

In order to ensure safe operation of a multi-phase system, even a system including a plurality of phases, a number of phase groups is provided, which comprises some of the phases, wherein phase currents of the number of phase groups are merged in a group node to form a group sum current and a group sum current measurement value of the group sum current is captured. The current measurement values belonging to the number of phase groups are summed up to form a group sum and the group sum is compared with the group sum current measurement value to validate the phase currents of the phases in order to ensure safe operation.

Various embodiments relate to detecting loss of electrical energy. A method of detecting loss of electrical energy may include determining, for a number of time samples, a neutral current and an imputed neutral current of an electrical energy metering system. Further, the method may include determining, for each of the number of time samples, a squared difference between the neutral current and the imputed neutral current. The method may further include detecting, based on the squared difference, loss of electrical energy from the electrical energy metering system.

Methods are described to provide a new and improved display of phase identification measurements in a three-phase power distribution network, that is easier and more intuitive to interpret and define tagging reference phase. A short sequence of individual phase measurements are displayed as dots inside a static phase attribute display circle. The 3 primary, 12 secondary, and 6 three-phase attributes are displayed around the outside of the phase circle. When using a touch screen Smartphone or Tablet display device, the user simply touches inside the phase circle to rotate the dots around the center of the phase circle, so they line up with the known conductor phase attribute. This rotation defines the tagging reference phase for the circuit.

Methods are described to provide a new and improved display of phase identification measurements in a three-phase power distribution network, that is easier and more intuitive to interpret and define tagging reference phase. A short sequence of individual phase measurements are displayed as dots inside a static phase attribute display circle. The 3 primary, 12 secondary, and 6 three-phase attributes are displayed around the outside of the phase circle. When using a touch screen Smartphone or Tablet display device, the user simply touches inside the phase circle to rotate the dots around the center of the phase circle, so they line up with the known conductor phase attribute. This rotation defines the tagging reference phase for the circuit.

Methods are described to provide a new and improved display of phase identification measurements in a three-phase power distribution network, that is easier and more intuitive to interpret and define tagging reference phase. A short sequence of individual phase measurements are displayed as dots inside a static phase attribute display circle. The 3 primary, 12 secondary, and 6 three-phase attributes are displayed around the outside of the phase circle. When using a touch screen Smartphone or Tablet display device, the user simply touches inside the phase circle to rotate the dots around the center of the phase circle, so they line up with the known conductor phase attribute. This rotation defines the tagging reference phase for the circuit.

Various embodiments relate to detecting theft of electrical energy. A method of detecting theft of electrical energy may include measuring, for each time sample of a number of time samples, a neutral current of an electrical energy metering system. The method may further include summing, for each time sample of the number of time samples, a number of measured phase current values of the electrical energy metering system to determine an imputed neutral current. Further, the method may include determining, for each time sample of the number of time samples, a squared difference between the measured neutral current and the imputed neutral current. Moreover, the method may include integrating, for each time sample of the number of time samples, the squared difference to determine an accumulator value. In addition, the method may include detecting, based on the accumulator value, theft of electrical energy from the electrical energy metering system.

A three-phase power meter can monitor power on both 3-wire and 4-wire power lines. The power meter measures at least two voltages between phase conductors of the power line, and at least one voltage between a phase conductor and a neutral conductor of the power line when the neutral conductor is available. Using at least some of the measured voltages, the power meter can then operate in a first mode when coupled to a 3-wire power line to determine power on the power line based on the measured voltages, or operate in a second mode when coupled to a 4-wire power line to determine power on the power line based on the measured voltages.