The invention relates to a method for detecting a direct-current fault current in an electrical alternating-current circuit, wherein a rectifier unit (14) is connected to an alternating-current network (34) by means of a primary side (13) and provides a direct current on a secondary side (15) and wherein the alternating-current network (34) is protected by means of a fault-current circuit breaker (38), which interrupts the circuit if an alternating-current fault current greater than a specified alternating-current tripping threshold occurs. A direct-current fault current on the primary side (13) is measured and is compared with a specified direct-current tripping threshold. An alternating-current fault current is produced if the direct-current fault current lies above the tripping threshold. The invention further relates to a device (10) for detecting a direct-current fault current and to a charging apparatus (12) comprising such a device (10).

A fault protection arrangement. The fault protection arrangement may include a neutral grounding resistor including a first non-ground end, connected to a neutralizing point, and a second non-ground end. The fault protection arrangement may include a neutral grounding resistance monitor assembly, directly coupled to the second non-ground end of the neutral grounding resistor. The neutral grounding resistance monitor assembly may include comprising a signal source coupled to the neutralizing-point; a first current sense circuit coupled between the signal source and the neutralizing-point; a first voltage sense circuit coupled between the signal source and the neutralizing-point; a second current sense circuit, comprising a current sensor, coupled between the second non-ground end of the neutral grounding resistor and a protective earth connection.

A system is described herein, including an activation circuit configured to generate a signal indicative of an alarm condition. A residual current device trigger circuit is coupled to the activation circuit and a residual current device. The residual current device trigger circuit is configured to provide a simulated earth leakage current condition to trigger the residual current device on receiving the signal indicative of the alarm condition.

Systems, methods, techniques and apparatuses of ground fault protection are disclosed. One exemplary embodiment is a power switch being structured to receive a load current from a power source at a source-side and selectively output the load current from a load-side to a load; a first voltage measuring device structured to measure a first voltage of the source-side while the power switch is conducting the load current; a second voltage measuring device structured to measure a second voltage of the load-side while the first voltage measuring device is measuring the first voltage; and a controller structured to determine a source-side-to-ground voltage based on the first voltage, determine a load-side-to-ground voltage based on the second voltage, determine a ground fault is occurring, and determine a direction of the ground fault relative to the power switch by comparing the source-side-to-ground voltage and the load-side-to-ground voltage.

The present disclosure relates to an earth leakage breaker and an arc detection apparatus attachable/detachable to/from the earth leakage breaker. An earth leakage breaker and an arc detection apparatus according to one embodiment of the present disclosure comprise: a body of the earth leakage breaker; and an arc detection module attachably/detachably coupled to the body of the earth leakage breaker so as to detect an arc current, wherein the arc detection module comprises: an arc detection unit connected to a first load side terminal of the body of the earth leakage breaker so as to detect an arc current flowing through a line; a control unit for determining an arc current on the basis of an arc detection signal delivered by the arc detection unit; and an output unit for outputting a signal or a current, according to a control signal of the control unit.

Arc fault current interrupter electrical devices and systems. An example is an electrical device comprising: a contact configured for electrical connection to a power line; at least one sensor to detect at least voltage signals indicative of the power line; and a processor configured to determine from the detected voltage signals that a series arc fault has occurred.

A fault protection arrangement. The fault protection arrangement may include a neutral grounding resistor including a first non-ground end, connected to a neutralizing point, and a second non-ground end. The fault protection arrangement may include a neutral grounding resistance monitor assembly, directly coupled to the second non-ground end of the neutral grounding resistor. The neutral grounding resistance monitor assembly may include comprising a signal source coupled to the neutralizing-point; a first current sense circuit coupled between the signal source and the neutralizing-point; a first voltage sense circuit coupled between the signal source and the neutralizing-point; a second current sense circuit, comprising a current sensor, coupled between the second non-ground end of the neutral grounding resistor and a protective earth connection.

In an electrical distribution system including a solid-state circuit breaker (SSCB) and one or more downstream mechanical circuit breakers (CBs), a solid-state switching device in the SSCB is repeatedly switched ON and OFF during a short circuit event, to reduce a root-mean-square (RMS) value of the short circuit current. The resulting pulsed short circuit current is regulated in a hysteresis control loop, to limit the RMS to a value low enough to prevent the SSCB from tripping prematurely but high enough to allow one of the downstream mechanical CBs to trip and isolate the short circuit. Pulsing is allowed to continue for a maximum short circuit pulsing time. Only if none of the downstream mechanical CBs is able to trip to isolate the short circuit within the maximum short circuit pulsing time is the SSCB allowed to trip.

Systems, methods, techniques and apparatuses of ground fault protection are disclosed. One exemplary embodiment is a power switch being structured to receive a load current from a power source at a source-side and selectively output the load current from a load-side to a load; a first voltage measuring device structured to measure a first voltage of the source-side while the power switch is conducting the load current; a second voltage measuring device structured to measure a second voltage of the load-side while the first voltage measuring device is measuring the first voltage; and a controller structured to determine a source-side-to-ground voltage based on the first voltage, determine a load-side-to-ground voltage based on the second voltage, determine a ground fault is occurring, and determine a direction of the ground fault relative to the power switch by comparing the source-side-to-ground voltage and the load-side-to-ground voltage.

In an electrical distribution system including a solid-state circuit breaker (SSCB) and one or more downstream mechanical circuit breakers (CBs), a solid-state switching device in the SSCB is repeatedly switched ON and OFF during a short circuit event, to reduce a root-mean-square (RMS) value of the short circuit current. The resulting pulsed short circuit current is regulated in a hysteresis control loop, to limit the RMS to a value low enough to prevent the SSCB from tripping prematurely but high enough to allow one of the downstream mechanical CBs to trip and isolate the short circuit. Pulsing is allowed to continue for a maximum short circuit pulsing time. Only if none of the downstream mechanical CBs is able to trip to isolate the short circuit within the maximum short circuit pulsing time is the SSCB allowed to trip.