A sensor circuit may comprise or otherwise be connected to a transformer. The transformer may comprise a primary winding and a secondary winding. The primary winding may be configurable and/or connectable to sense a current flow in the primary winding. A configurable circuit with an output may be connected to the input of a comparator circuit. The output of the comparator circuit and one or both of the input of the configurable circuit or the output of the configurable circuit may connect across the secondary winding.

A current-measuring transducer device has a current transducer for measuring an electric current along a conduction path. The current transducer has a magnetic field-sensitive element for converting the magnetic field resulting from the current flow along the conduction path into at least one physical variable and a measuring device for measuring the physical variable. The current transducer device has a coil arrangement with at least one coil for simulating the magnetic field resulting from the current flow along the conduction path. There is also described a method for calibrating a corresponding current transducer and a computer program product for performing the calibration method.

An electrical power converter (1, 1′, 1″) includes a DC link capacitor (3, 3′, 3″) configured for connection to a DC power source to provide an input load, at least one pair of semiconductor switches (2a, 2b, 2c, 2a′, 2b′, 2a″, 2b″) connected in parallel with the DC link capacitor (3, 3′, 3″) and positioned on either side of an output load terminal (10a, 10b, 10c, 10a′, 10b′, 10a″, 10b″). The electrical power converter (1, 1′, 1″) further includes an inductive current sensor (12, 12′, 12″), arranged to sense a primary current from a terminal of the DC link capacitor (3, 3′, 3″), and a detection circuit (14), connected to the inductive current sensor (12, 12′, 12″) and arranged to monitor for an over-current condition, and to produce an output which causes at least one of the pair of semiconductor switches (2a, 2b, 2c, 2a′, 2b′, 2a″, 2b″) to be switched to a non-conducting state when an over-current condition is detected.

A Rogowski coil is used for determining the magnitude of the electrical current of a conductor of a low-voltage AC circuit, which outputs an analogue voltage which is equivalent to the magnitude of the electrical current of the conductor. The Rogowski coil is connected to an analogue integrator, which is followed by an analogue-digital converter, which converts the integrated analogue voltage into a digital signal which is further processed by a microprocessor in such a way that the phase shift generated by the Rogowski coil and the components connected downstream of the Rogowski coil is compensated such that there are in-phase current values for the detection of error situations in order to protect the low-voltage AC circuit, in particular for a low-voltage power switch or an arc fault detection unit.

A method for the onsite calibration of a Rogowski sensor to be calibrated, includes the steps of: cause the sensor to be calibrated to be positioned on a reference phase, or cause a reference sensor to be positioned on the phase to be calibrated; acquiring a calibration current measurement produced by the sensor to be calibrated, a reference current measurement produced by the reference sensor, and a reference voltage measurement on the phase on which are positioned the reference sensor to be calibrated following the positioning step; and using the calibration current measurement, the reference current measurement and the reference voltage measurement to produce calibration parameters of the sensor to be calibrated.

Systems, methods, and devices are provided for controlling part of an electric power distribution system using an intelligent electronic device that may rely on communication from wireless electrical measurement devices. Wireless electrical measurement devices associated with different phases of power on an electric power distribution system may send wireless messages containing electrical measurements for respective phases to an intelligent electronic device. When wireless communication with one of the wireless electrical measurement devices becomes inconsistent or lost, the intelligent electronic device may synthesize the electrical measurements of the missing phase using electrical measurements of remaining phases. The intelligent electronic device may use the synthesized electrical measurements to control part of the electric power distribution system.

An apparatus and a tool for installation of a measurement coil. The apparatus includes a tool and a holder. The tool includes a first portion and a second portion at least partially surrounding the first portion. The first portion is configured to receive a conductor and the second portion is configured to hold a measurement coil. The holder is configured to be detachably attached to the tool, wherein the holder is to be employed to install the tool holding the measurement coil onto a conductor. The first portion is configured to snap fit onto the conductor during installation, and the measurement coil at least partially surrounds the conductor when installed.

A system for distribution transformer monitoring may comprise a distribution transformer that includes a transformer fluid tank, a monitoring unit that includes a plurality of sensors, wherein the monitoring unit is coupled to the distribution transformer, and wherein the plurality of sensors comprises a fluid sensor that includes a sensor probe that extends out of the monitoring unit into the transformer fluid tank of the distribution transformer, and a communication unit coupled to the distribution transformer and communicatively coupled to the monitoring unit. The monitoring unit may further comprises a sensor module to receive sensor data from the plurality of sensors, a storage module to store the sensor data in an internal data storage device of the monitoring unit, an analysis module to analyze the sensor data to determine generated data, and a communication module to communicate the sensor data or the generated data to a remote computing device.

A low-noise current sensor enables large dynamic range current measurements of alternating and direct current flows. The current sensor includes a first substrate, a first conductor, a magnetic flux conductor comprising a first portion orthogonal to the first conductor and a second portion, the second portion penetrating the first substrate, an inductive sensor comprising a first plurality of loops around the second portion of the magnetic flux conductor on the first substrate, wherein the first plurality of loops is orthogonal to the second portion of the magnetic flux conductor, and a Faraday cage that encloses the first plurality of loops and separates the first plurality of loops from the first conductor.

A low-noise current sensor enables large dynamic range current measurements of alternating and direct current flows. The current sensor includes a first substrate, a first conductor, a magnetic flux conductor comprising a first portion orthogonal to the first conductor and a second portion, the second portion penetrating the first substrate, an inductive sensor comprising a first plurality of loops around the second portion of the magnetic flux conductor on the first substrate, wherein the first plurality of loops is orthogonal to the second portion of the magnetic flux conductor, and a Faraday cage that encloses the first plurality of loops and separates the first plurality of loops from the first conductor.