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.

An arc detection device includes: a current detector that includes a magnetic core penetrated by first and second paths and each connecting a DC power source and a device, and detects a current flowing through each of the first and second paths and in accordance with a magnetic field generated at the magnetic core; a low impedance circuit having a lower impedance than the DC power source and the device, the low impedance circuit being connected to the first path and the second path to cause a high frequency component to bypass one of the first path or the second path; and an arc determiner that determines an occurrence of an arc based on a current detected by the current detector. In the magnetic core, a direct current flows through the first path in a direction opposite to a direction in which a direct current flows through the second path.

A diagnostic device includes electrical connectors, load, power supply, switching circuitry, sensors, and processor. The connectors include first and second sets of terminals for connecting to the conductors of a branch circuit in an upstream and downstream direction, respectively, at an outlet location along the circuit. The switching circuitry can isolate the upstream and downstream sections of the circuit from the outlet location, and selectively connect or disconnect the power supply or the load to the upstream or downstream section. The sensors measure electrical characteristics on the conductors of the circuit to monitor load currents, such as on power, neutral and ground lines, of the upstream and downstream circuit sections. The processor controls the switching circuitry, and obtains diagnostic information corresponding to the monitored load currents on the upstream and downstream sections of the branch circuit, from the measurements performed by the sensors.

An arrangement for detecting arcs in a low-voltage circuit has at least one voltage sensor for periodically determining voltage values of the low-voltage circuit and at least one current sensor for periodically determining current values of the low-voltage circuit. A first control unit is connected to the voltage sensor and the current sensor, has a processor, and is configured in such a way that the presence of a switch arc is determined on the basis of the determined voltage values and current values. A switch arc detection signal is output if a switch arc is determined to be present.

An electrical device includes a first terminal structured to electrically connect to a power source; a second terminal structured to electrically connect to a load; a voltage sensor electrically connected to a point between the first and second terminals and being structured to sense a voltage at the point between the first and second terminals; a switch electrically connected between the first terminal and the second terminal; and a control unit structured to detect a power quality event in the power flowing between the first and second terminals based on the sensed voltage and to control a state of the switch based on the detected power quality event.

Various embodiments disclosed herein provide techniques for detecting electrical arcing in an electrical system. A powerline communications (PLC) application executing on a network communications device acquires, via a PLC modem, first voltage readings associated with an electrical circuit. The PLC application performs one or more operations based on the first voltage readings to determine that an electrical arcing condition is present within the electrical circuit. The PLC application performs a remedial operation in response to determining that the electrical arcing condition is present.

A method for processing a direct current electric arc and an apparatus, includes: obtaining a first current which is a direct current input current of a direct current cable of a photovoltaic cell system; obtaining a second current, where the second current is a direct current common mode current of a direct current cable or an alternating current common mode current of an alternating current cable; calculating a correlation coefficient between a frequency domain component of the first current and a frequency domain component of the second current; and when determining that the first current meets an electric arc occurrence condition and the correlation coefficient is greater than or equal to a preset coefficient threshold, skipping sending a direct current electric arc fault alarm. The correlation coefficient is used to reflect a proportion of common mode noise generated by the second current, and the preset coefficient threshold is set.

A crowbar module includes first and second electrical terminals, a module housing, and first and second crowbar units. The first crowbar unit is disposed in the module housing and includes a first thyristor electrically connected between the first and second electrical terminals. The second crowbar unit is disposed in the module housing and includes a second thyristor electrically connected between the first and second electrical terminals in electrical parallel with the first crowbar unit.

A fault-arc identification method, device and apparatus, and a storage medium. The method comprises: performing sampling on a target arc at a high frequency, and obtaining a high-frequency sampling signal (S11); preprocessing the high-frequency sampling signal, and obtaining a processed sampling signal (S12); performing feature extraction on the processed sampling signal, and obtaining a target arc feature (S13); and inputting the target arc feature to a neural network model, obtaining a target output result, and determining, according to the target output result, whether the target arc is a fault-arc (S14). Performing sampling on a target arc at a high frequency can obtain more arc features from the target arc. Moreover, since a neural network model has favorable data classification capability, using a neural network model to perform determination with respect to the target arc can improve the accuracy and reliability of a fault-arc detection result.

Arc fault protection for a digital electricity distribution system that provides power to a device. The system includes an arc fault circuit interrupter (“AFCI”) and a controller. The controller is connected to the AFCI. The controller is operable to control the AFCI to disable power to the device. The controller includes a processor and a memory. The controller is configured to transmit a digital electricity energy packet through the AFCI to the device, measure an amount of error associated with the digital electricity energy packet, evaluate the amount of error associated with the digital electricity energy packet, determine whether an arc fault condition is present based on the evaluation of the amount of error associated with the digital electricity energy packet, and control the AFCI to disable power to the device when the arc fault condition is determined to be present.