A method includes performing by a processor: receiving a plurality of power system synchrophasor measurements over a time interval from a plurality of phasor measurement units (PMUs) in a power system, determining a variation in frequency of a power signal generated by the power system based on the plurality of power system synchrophasor measurements, and determining a clock time shift based on the variation in frequency of the power signal.

Approaches for testing phase rotators are provided. A circuit for testing phase rotators includes a compare element including a first input and a second input, wherein the compare element is configured to compare a first phase of a first signal provided at the first input to a second phase of a second signal provided at the second input. The circuit also includes a first test bus connected to the first input and a second test bus connected to the second input.

Boundary test circuit, memory and boundary test method are provided. The boundary test circuit may include a plurality of serially-connected wrapper boundary registers (WBRs) and a plurality of toggle circuits (TCs). Each WBR may include a first I/O for receiving an initial test signal and a second I/O for transmitting the initial test signal to the WBR at a succeeding stage. Each TC may include an input for receiving the initial test signal stored in a corresponding WBR, a control I/O for receiving a toggle signal, and an output for transmitting a real-time test signal to the integrated circuit. The toggle signal may be configured to control phase switching of the real-time test signal, and, depending on the toggle signal, the real-time test signal may have a phase identical or inverse to a phase of the initial test signal. This method improves the efficiency and flexibility of the boundary test.

Methods, systems, and apparatus, including computer programs stored on a computer-readable storage medium, for obtaining a reference phase signal that is synchronized with an alternating current (AC) phase of a multi-phase electrical power distribution system. The apparatus obtains output signals from sensors, each output signal representative of an electromagnetic emission detected by a respective sensor. The apparatus identifies, based on comparing respective phases of the output signals to the reference phase signal, a particular AC phase of the multi-phase electrical power distribution system associated with a source of the emissions. The apparatus provides an indication of the particular AC phase to a user.

Methods, systems, and apparatus, including computer programs stored on a computer-readable storage medium, for obtaining a reference phase signal that is synchronized with an alternating current (AC) phase of a multi-phase electrical power distribution system. The apparatus obtains output signals from sensors, each output signal representative of an electromagnetic emission detected by a respective sensor. The apparatus identifies, based on comparing respective phases of the output signals to the reference phase signal, a particular AC phase of the multi-phase electrical power distribution system associated with a source of the emissions. The apparatus provides an indication of the particular AC phase to a user.

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.

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.

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.