A short circuit protection apparatus for a power conversion apparatus supplying power to a load via a plurality of switches connected to each other in parallel includes Ma current detectors each configured to detect a sum of currents flowing through two or more switches among the plurality of switches so as to output a detection signal indicative of the sum that is detected, wherein Ma is 1 less than M, which is the number of the plurality of switches, and a short circuit determiner configured to determine, based on detection signals obtained from the respective Ma current detectors, occurrence of short circuit failure in the plurality of switches to output a cutoff instruction signal for stopping on-off drive of the plurality of switches.

An apparatus for identifying a fault in the windings of a distribution transformer, a transformer, and an associated method, said device comprising: a first Rogowski current sensor at a high-voltage incoming current terminal, and a second Rogowski current sensor in tandem at a low-voltage outgoing current terminal and at a low-voltage incoming current terminal; a first conductor of the low-voltage outgoing current terminal, passed through in one direction through the second sensor, and a second conductor of the low-voltage incoming current terminal, passed through in the opposite direction through the second sensor; the first and second sensors generate output signals indicating the primary current and the secondary current; both signals are integrated, generating output signals proportional to the primary current and the secondary current, obtaining a transformation ratio, which is compared with a threshold, and sending a fault signal if said threshold is exceeded.

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.

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 current sense system may include a relay, a load conductor, and an integrator sub-circuit. Current may be provided to an electrical load via the load conductor and a latch of the relay. The current carried via the load conductor may induce a sense voltage in a coil of the relay. Based on the sense voltage induced in the relay coil, the integrator sub-circuit may determine a load sense voltage that indicates a level of the current carried via the load conductor. In some implementations, a current indication module may provide an indicator signal based on the load sense voltage. In addition, the indicator signal may be provided to additional components or devices, such as a relay controller configured to activate the latch. In some implementations, the relay controller may be configured to open the latch based on the current level described by the indicator signal.

One or more implementations of the present disclosure are directed to sensor probes of measurement systems for measuring a plurality of electrical parameters, (e.g., voltage, current) of a conductor and methods for measuring same. In at least one implementation, the sensor probe integrates a Rogowski coil and a non-contact voltage sensor that are arranged relative to each other such that when positioned to measure a conductor, such as a wire, the Rogowski coil and the non-contact voltage sensor are held in proper position for measurement.

The invention relates to a surge protection device intended to be installed on an electrical installation, in parallel with one or more items of equipment to be protected, said electrical installation comprising at least one first phase line (L1), a neutral line (N) and an earth line (T), the protection device comprising a casing; and a current measurement toroid, which is housed in the casing and which comprises a central opening, through which a detection portion passes that is disposed in a surge current diversion path.