A direct-current circuit breaker includes a first main circuit breaker inserted into a first direct-current line, a resonance circuit connected in parallel to the first main circuit breaker, a MOSA connected in parallel to the first main circuit breaker via the resonance circuit, a second main circuit breaker inserted into a second direct-current line, a switch connected in series to the second main circuit breaker, a resonance circuit connected in parallel to the second main circuit breaker, and a MOSA connected in parallel to the second main circuit breaker via the resonance circuit. The second direct-current line is a line that branches off from the first direct-current line and returns to the first direct-current line. The switch is inserted upstream of the second direct-current line.

A current converter unit for a high-voltage direct-current (HVDC) transmission contains a first converter and a second converter. A first direct-current terminal of the first converter is connected to a first conductor terminal point for a first HVDC transmission conductor. A second direct-current terminal of the first converter is connected to a first direct-current terminal of the second converter such that a connection point is formed. A second direct-current terminal of the second converter is connected to a second conductor terminal point for a second HVDC transmission conductor. The connection point is connected to ground potential by a current-damping electric component, and the connection point is connected to the ground potential by a direct-current switch.

An object is to provide a DC distribution panel that, even when short-circuit current has occurred in one feeder, interrupts only the feeder where short-circuit current has occurred, and thus can continue operations of load apparatuses connected to normal feeders. This DC distribution panel includes: an input terminal including positive and negative input terminals; circuit breakers having short-circuit current interruption units connected to at least either of positive electric paths and negative electric paths respectively branched from the positive and negative input terminals; and output terminals including positive output terminals and negative output terminals of the plurality of circuit breakers. At least one of the plurality of circuit breakers includes a reverse current interruption unit for interrupting reverse current flowing through the positive electric path from the output terminal side to the input terminal side.

An isolation disconnect assembly for an insulated gate bipolar transistor assembly is provided. The isolation disconnect assembly includes a conductor assembly and a clinch joint magnetic actuator.

A current cut-off device for high-voltage DC current includes: between a primary point and an intermediate point, a primary diversion member and, in parallel, a primary surge protector; a secondary mechanical switch between the intermediate point and the secondary point; a main resonator whose terminal is linked to the secondary point; a main oscillation switch; a main surge protector, in parallel with a main capacitance of the main resonator; wherein the main oscillation switch includes three terminals linked respectively to the primary point, to the intermediate point and to the other terminal of the main resonator; the changeover switch can switch at least between three direct, inverting and isolated states.

An electric grid includes feed-ins, loads, and a distribution grid, which is arranged therebetween. The distribution grid comprises at least one busbar and at least one device for opening or closing a DC circuit. The at least one device includes an electric switch for opening or closing the DC circuit, a fault current detector, a trigger unit, a precharging device, and a control unit for automatically closing the electric switch after the precharging process. The electric switch opens the DC circuit via the trigger unit if a fault current is detected by the fault current detector, and the precharging device restores the voltage on the busbar prior to closing the electric switch.

The present disclosure provides a DC mechanical circuit breaker that can utilize two switches, one of which can generate zero-crossing with an alternate oscillatory circuit for the other one, which can be a conventional zero-crossing-based AC breaker and can be used in the main circuit. This is different from the conventional single-switch commute-and-absorb method currently used. The present disclosure shows that disclosed circuit breaker improves the fault current extinction and significantly reduces the voltage rate-of-change while creating the current zero-crossing faster compared to the available technology. Thus, disclosed circuit breaker is capable of interrupting high DC currents with minimal arc through a less expensive AC circuit breaker. Simulation and hardware results are provided to show the efficiency of the disclosed circuit breaker.

A circuit breaker includes a circuit breaker housing, an air-gap switch disposed within the housing, and a first visual indicator configured to provide an indication of an open state and a closed state of the air-gap switch. The first visual indicator includes a first window that is formed as part of the circuit breaker housing, and first and second indicator elements disposed within the circuit breaker housing. The first indicator element is configured to move into position behind the first window as the air-gap switch is placed into the open state and thereby provide a visual indication of the open state of the air-gap switch. The second indicator element is configured to move into position behind the first window as the air-gap switch is placed into the closed state and thereby provide a visual indication of the closed state of the air-gap switch.

A medium-voltage switchgear system includes a three-phase circuit breaker having first, second and third single-phase vacuum interrupters connected between respective first, second and third single-phase inputs and first, second and third single-phase outputs. Magnetic actuators are connected to first, second and third single-phase vacuum interrupters, which are configured to receive an interrupt signal and in response, actuate the respective vacuum interrupter connected thereto into an open circuit condition. A controller circuit is connected to each of the first, second and third magnetic actuators and generates an interrupt signal in response to a detected single-phase overcurrent or fault on a single-phase circuit and interrupt that single-phase circuit on which the single-phase overcurrent or fault occurred and maintain power on the remaining two single-phase circuits over which a single-phase overcurrent or fault was not detected.

A circuit breaker for interrupting a direct current, in particular in a power supply system in a vehicle having a main current path that includes a switch, and having a reed relay for detecting an electric current flow across the main current path. The switch is coupled to the reed relay. Also, a use of a circuit breaker is provided.