A superconducting arcing induction type DC circuit breaker includes a superconducting fault current limiter and an arcing induction type DC circuit breaker connected in series to each other. The arcing induction type DC circuit breaker includes an induction member that has a through-hole, is continuously formed in a 360-degree direction, and has a certain shape and thickness, and an induction needle that protrudes from an inner surface of the induction member toward a center of the induction member. A contact point where an anode and a cathode, which are mechanical contacts, approach from opposite directions and come into contact with each other is formed in the through-hole of the induction member, and the anode and the cathode are separated in a direction far away from each other. The induction needle induces arc generated upon contact opening when the anode and the cathode are separated from each other in the event of system accident of DC power or AC power, and the induction member quenches the induced arc by the flow of the induced arc to ground through a ground line.

A method for switching an operating current in a meshed DC voltage network enables operating currents in a DC voltage network to be switched economically in both directions. At least one converter connected to the DC voltage network is controlled in such a way that a zero current is generated in a switching branch having a mechanical switch and the mechanical switch is actuated in accordance with the generated zero current.

A commutating circuit breaker that works by progressively inserting increasing resistance into a circuit. This is done via physical motion of a shuttle that is linked into the circuit by at least one set of sliding electrical contacts on the shuttle (“shuttle electrodes”) that connect the power through the moving shuttle to a sequence of different resistive paths with increasing resistance; the motion of the shuttle can be either linear or rotary. A feature of the commutating circuit breaker is that at no point are the shuttle electrodes separated from the matching stationary stator electrodes so as to generate a powerful arc, which minimizes damage to the electrodes. Instead, the current is commutated from one resistive path to the next with small enough changes in resistance at each step that arcing can be suppressed. The variable resistance can either be within the moving shuttle, or the shuttle can comprise a commutating shuttle that moves the current over a series of stationary resistors. In either case, a “soft” opening of the circuit can be accomplished, with low switching transients, provided that the maximum step change of resistance is limited until the current is nearly extinguished. Commutating circuit breakers work equally well for DC or AC power.

A mechanical switch that works by commutation of the current to an energy absorbing path or sequence of paths through at least one blocking semiconductor to open the circuit, wherein the commutation is caused by a sliding motion of at least one shuttle electrode over at least one stationary electrode.

A circuit breaker/disconnector apparatus for use in a power delivery system comprises a unidirectional DC circuit breaker which has a first terminal and a second terminal and is configured to automatically open during an overcurrent condition in a forward direction and to remain closed independent of current level in a reverse direction. A disconnector switch is in series with the circuit breaker. The disconnector switch has a first terminal for connecting to a first polarity connector of a power supply, a second terminal for connecting to a second polarity connector of the power supply and a common terminal connected to the first terminal of the circuit breaker. The disconnector switch has at least a first position in which the first terminal is connected to the common terminal and a second position in which the second terminal is connected to the common terminal. The second polarity connector of the power supply may be coupled to a track of a transport system and the second polarity connector of the power supply may be coupled to a live overhead cable or live third rail of a transport system. The apparatus can be used to safely ground the live cable or third rail when in a maintenance condition.

A DC circuit breaker includes: a mechanical switch provided on an electrical path through which a direct current flows; and a semiconductor switch connected in parallel with the mechanical switch. The mechanical switch includes a gas disconnector and a vacuum circuit breaker connected in series. Normally, the direct current flows through the mechanical switch. When interrupting the direct current, the vacuum circuit breaker is made nonconductive to allow the direct current to be commutated to the semiconductor switch, and subsequently the gas disconnector and the semiconductor switch are made nonconductive. A vacuum circuit breaker having a low withstand voltage can be used.

Disclosed herein is a current circuit breaker that protects a semiconductor module by using fast switches to block a current. The current circuit breaker includes: a first switch configured to be opened upon a fault current being generated; a second switch connected to the first switch and configured to be opened after a predetermined period of time elapses since the first switch has been opened; a semiconductor module having an end connected to the first switch and another end connected to the second switch; a capacitor having a terminal connected to the second switch and the other terminal connected to the semiconductor module; and a surge arrester connected across the capacitor and configured to change its resistance according to a voltage across the capacitor to block the fault current.

The circuit breaker includes two polarities each including two poles connected in parallel, each pole having a switch and a tripping device. Each of the polarities has an equalizer electrically connecting the link between the switch and the tripping device of a first pole and the link between the switch and the tripping device of the second pole.

Devices, methods and techniques are disclosed to interrupt a fault current in a high-voltage direct-current circuit. In one example aspect, a device includes a mechanical switch including a pair of contacts configured to be positioned apart upon activation of the circuit breaker, and a photoconductive component connected in parallel with the mechanical switch. The photoconductive component is configured to establish a current upon activation of the circuit breaker. The photoconductive component comprises a crystalline material positioned to receive a pulsed light signal from a laser light source, and a pair of electrodes coupled to the crystalline material and configured to allow an electric field to be established across the crystalline material to generate the current.

A T-breaker is an all-in-one solution for dc microgrid fault protection, power flow control, and power quality improvement. A T-breaker features a modular multilevel “T” structure with integrated energy storage devices. The two horizontal arms of the T-breaker realize fault current breaking, load voltage compensation, and power flow control; and the vertical arm of the T-breaker realizes shunt compensation. The configuration provides excellent voltage scalability and relaxes the requirements on the switching signal synchronization during fault transients. The local energy storage in sub-modules eases the fault energy dissipation requirement placed on the traditionally-adopted surge arrestors. The modular multilevel structure also offers immense control flexibility for all types of targeted functions of the provided T-breaker.