A direct-current circuit breaker includes a circuit breaker unit and a circuit unit that generates an oscillating current. The circuit unit includes a capacitor and a reactor, a high-speed closer, and a lightning arrester. The circuit breaker unit and the high-speed closer are aligned in a first direction with a distance therebetween that is equal to or longer than a certain spatial distance. The capacitor and the lightning arrester are aligned in a second direction intersecting the first direction with a distance therebetween that is equal to or longer than the spatial distance. A combination of the circuit breaker unit with the high-speed closer and a combination of the capacitor with the lightning arrester are aligned in a third direction intersecting the first direction and the second direction with a distance therebetween that is equal to or longer than the spatial distance.

A switching apparatus comprises: a first current-conductive branch (12) including a first switching element (24), the first switching element (24) configured to be switchable to selectively permit and block a flow of current in the first current-conductive branch (12); a second current-conductive branch (14) including a second switching element (32), the second switching element (32) configured to be switchable to selectively permit and block a flow of current in the second current-conductive branch (14); and first and second terminals (18,20) for connection, in use, to an electrical network (22), wherein the first and second current-conductive branches (12,14) extend between the first and second terminals (18,20), wherein the first current-conductive branch (12) further includes an energy storage element electrically coupled to the second switching element (32) so that the energy storage element is configured as a power source for enabling the operation of the second switching element (32), and the first switching element (24) is configured to be switchable to selectively direct a current flowing in the first current-conductive branch (12) to flow through the energy storage element so as to store energy in the energy storage element.

A low-voltage circuit breaker includes at least one current sensor for determining the magnitude of the electric current of a conductor of the low-voltage circuit breaker; and at least one electromechanical switching unit for connecting and disconnecting at least two electrical contact points. In a first switching position of the movable contact point, two contact points are connected and in a second switching position the contact points are not connected to one another. The circuit breaker further includes at least one electronic switching unit having a semiconductor switching element, electrically conductive in a first switching state and electrically blocking in a second switching state; an electronic tripping unit, connected to the current sensor, the electronic switching unit and the electromechanical switching unit. Further, when current and/or current/time-period limit values of the conductor are exceeded, first the electromechanical switching unit is opened and then the electronic switching unit is blocked.

A switching apparatus for safely disconnecting an electrical load from a power supply network and to facilitate safe disconnection in the event of failure of a supply voltage thereof, includes an energy storage device which, in the event of failure of the supply voltage of a control unit, provides the energy for generating switching signals for a first electromechanical switch, a second electromechanical switch and a semiconductor switch. In order to be able to detect the failure of the supply voltage, a detector and signaling device is provided which is configured to detect discharging of the energy storage device and to supply a notification signal to the control unit signaling the discharging of the energy storage device to the control unit. In response to the notification signal, the control unit causes the electrical load to be disconnected from the power supply network in a safe and terminal-friendly manner.

A circuit breaker and method of operation. The circuit breaker includes a first current path including a mechanical switch, such as an ultrafast mechanical switch, and a second current path in parallel connection to the first current path, and including a current injector, such as a transient commutation current injection circuit, in series with bidirectional power electronic switch. A short circuit fault current from a mechanical switch path is communicated to the electronic path via a current injection, followed by interrupting the fault current. A pulse current is generated to the electronic switch in the second current path, and the mechanical switch is opened during the pulse current. The pulse current and the electronic switch reduce or eliminate arcing upon the opening the mechanical switch.

An arc flash mitigation system includes a main circuit protector such as a high amperage overcurrent protection fuse, and an arc flash mitigation network connected in parallel to the main circuit protector. The arc flash mitigation network includes at least one semiconductor switch operable to provide a shunt current path to a low amperage arc mitigation fuse for a faster response time to certain circuit conditions than the main circuit protector otherwise provides. The semiconductor switch may be a silicon controller rectifier operatively responsive to a voltage drop across the main circuit protector in use.

A low-voltage circuit protection device includes: at least one outer conductor section from an outer conductor supply terminal of the low-voltage circuit protection device to an outer conductor load terminal of the low-voltage circuit protection device; a neutral conductor section from a neutral terminal of the low-voltage circuit protection device to a neutral load terminal of the low-voltage circuit protection device; an electrical measuring arrangement; at least one semiconductor circuit arrangement; and an electronic control unit which is connected to the electrical measuring arrangement and the semiconductor circuit arrangement. The measuring arrangement and/or the electronic control unit detects a predetermined combination of at least two electrical faults selected from the group including: overvoltage, undervoltage and overcurrent. The semiconductor circuit arrangement provides a specifiable reduction of an output voltage applied at the outer conductor supply terminal and the neutral conductor load terminal.

A circuit breaker includes a solid-state switch, a sense resistor, a current detection circuit, and a switch control circuit. The solid-state switch and sense resistor are connected in series in an electrical path between a line input terminal and a load output terminal of the circuit breaker. The current detection circuit is configured to (i) sample a sense voltage that is generated across the sense resistor in response to load current flowing through the sense resistor, (ii) detect an over-current fault condition based on the sampled sense voltage, and (iii) output a fault detection signal in response to detecting the over-current fault condition. The switch control circuit is configured to control the solid-state switch, wherein the switch control circuit is configured to switch off the solid-state switch in response to the fault detection signal output from the current detection circuit.

A low-voltage circuit breaker device includes: at least one line conductor path from a line conductor supply connection of the low-voltage circuit breaker device to a line conductor load connection of the low-voltage circuit breaker device; a neutral conductor path from a neutral conductor connection of the low-voltage circuit breaker device to a neutral conductor load connection of the low-voltage circuit breaker device; a mechanical bypass switch arranged in the line conductor path; a first semiconductor circuit assembly of the low-voltage circuit breaker device being connected in parallel with the mechanical bypass switch; an electronic control unit for actuating the mechanical bypass switch and the first semiconductor circuit assembly; an ammeter assembly arranged in the line conductor path, which ammeter assembly is connected to the electronic control unit; and a second semiconductor circuit assembly arranged in the line conductor path.

Compliant electrical circuit protection devices are described for use in hazardous environments without presenting ignition risks for potentially explosive environmental conditions. Sensing features and systems may evaluate wiring limits and user selected settings for compatibility, detect loose connections and operating parameters to ensure safe operation of the device, and to intelligently diagnose and manage issues of concern for the circuit protection devices as well as the larger electrical power system.