An electromechanical switching protection system includes an electromechanical switchgear having contacts configured to selectively open and close in response to a control signal, and a junction field effect transistor (JFET) device electrically connected in series with the electromechanical switchgear between an input terminal and an output terminal of the electromechanical switching protection system, a gate of the JFET device being electrically connected to the output terminal.

Device, circuit, system, and method for contact sequencing are discussed. An electrical circuit includes a first pair of terminals adapted to be connected across a first set of switchable contacts, and a second pair of terminals adapted to be connected across a second set of switchable contacts that are coupled to an arc suppression circuit. A controller circuit is coupled to the first and second pairs of terminals and is configured to sequence activation or deactivation of the first and second sets of contacts based on a contact control signal. A first power switching circuit is coupled to the first pair of terminals and the controller circuit. The first power switching circuit is configured to switch power from an external power source and to trigger the activation or the deactivation of the first set of switchable contacts based on a first logic state signal from the controller circuit.

A two terminal arc suppressor for protecting switch, relay or contactor contacts and the like comprises a two terminal module adapted to be attached in parallel with the contacts to be protected and including a circuit for deriving an operating voltage upon the transitioning of the switch, relay or contactor contacts from a closed to an open disposition, the power being rectified and the resulting DC signal used to trigger a power triac switch via an optoisolator circuit whereby arc suppression pulses are generated for short predetermined intervals only at a transition of the mechanical switch, relay or contactor contacts from an closed to an open transition and, again, at an open to a close transition during contact bounce conditions.

A power contact health assessor system includes a pair of terminals adapted to be connected to a set of switchable contact electrodes of a power contact and a contact separation detector configured to determine a time of separation of the set of switchable contact electrodes during deactivation of the power contact. The system includes a controller circuit operatively coupled to the pair of terminals and the contact separation detector. The controller circuit is configured to determine within a first observation window, a plurality of contact stick durations and an average contact stick duration. One or more additional observation windows with corresponding average contact stick durations are configured. A health assessment for the set of switchable contact electrodes may be based on a subsequent contact stick duration for a contact cycle after the first observation window and the corresponding average contact stick durations for the one or more additional observation windows.

Provided are a method and apparatus for calculating fault resistance and a current-limiting current of a superconducting fault current limiter. The method includes: calculating a first short-circuit fault current I.sub.n(t) of a power grid short-circuit fault transient circuit calling an external characteristic model U(I, t), and calculating resistance R.sub.n(t) of a superconducting fault current limiter under the first short-circuit fault current I.sub.n(t); adding the resistance R.sub.n(t) of the superconducting fault current limiter into the power grid short-circuit fault transient circuit, and calculating a second short-circuit fault current I.sub.m(t), where m=n+1; and determining whether an error between the second short-circuit fault current I.sub.m(t) and the first short-circuit fault current I.sub.n(t) is smaller than a preset threshold value, if yes, determining the fault resistance and the current-limiting current of the superconducting fault current limiter to be R.sub.n(t) and I.sub.m(t) respectively; otherwise I.sub.n(t)=I.sub.m(t), returning for iteration.

A switching device is for a low-voltage electric circuit having a plurality of conductors. In an embodiment, the switching device includes a housing having connection contacts arranged on the housing for connection of conductors of the low-voltage electric circuit; and a mechanical unit situated in the housing having an isolating function and an OFF or IN position, the mechanical unit including isolating contacts for galvanically interrupting the conductors of the low-voltage electric circuit. An electronic unit is provided which is connected to the mechanical unit in series on the current flow side; an auxiliary switch connected to the mechanical unit is provided and is connected in turn to the electronic unit; and the auxiliary switch and the electronic unit are designed in such a way that the electronic unit is highly resistive during an opening process of the mechanical unit.

A hybridization system for an electric device having two terminals and two states including a closed state allowing an electric current to circulate between the two terminals and an open state blocking the circulation of the electric current between the terminals, the device being suitable for an electric arc to be generated during the switching from the closed state to the open state. The hybridization system includes: two conductors connected to the two terminals of the electric device; a timer switch having two terminals connected to the two conductors and the timer switch being suitable for being in the open state by default and, after a first predetermined duration following the triggering of the electric arc, switching to the closed state for a second predetermined duration, and an electric power supply of the timer switch, connected to the two conductors in order to derive its power only from the electric energy provided by the electric arc.

A circuit breaker is proposed, comprising a live line and a neutral line and a semiconductor switching unit located in the live line, the circuit breaker further comprises a bypass line, which is connected in parallel to the semiconductor switching unit, with a first mechanical switch and a second mechanical switch located in the bypass line, with the first mechanical switch connected in series to the second mechanical switch, whereby the semiconductor switching unit, the first mechanical switch and the second mechanical switch are controlled by a processing unit of the circuit breaker, which is embodied to send a first opening command to the first mechanical switch in case of a short-circuit-detection, and sending a second opening command to the second mechanical switch a time-delay after sending of the first opening command.

The present disclosure relates to a micro-loss combined mechanical DC circuit breaker and its control method, consisting n ports, n load current paths and a main breaker; wherein the n load current paths are parallel with the main breaker, and each load current path is divided into an upper bridge arm and a lower bridge arm at a connection point; each port is electrically connected to the connection point of a load current path; the upper bridge arm of each load current path is made of an ultra-fast mechanical switch; the lower bridge arm of each load current path is made of a residual current breaker and a fast closing switch; the main breaker consists of a high-voltage capacitor in series with a low-voltage capacitor that is pre-charged.

A power contact health assessor system includes a pair of terminals adapted to be connected to a set of switchable contact electrodes of a power contact and a contact separation detector configured to determine a time of separation of the set of switchable contact electrodes during deactivation of the power contact. The system includes a controller circuit operatively coupled to the pair of terminals and the contact separation detector. The controller circuit is configured to determine within a first observation window, a plurality of contact stick durations and an average contact stick duration. One or more additional observation windows with corresponding average contact stick durations are configured. A health assessment for the set of switchable contact electrodes may be based on a subsequent contact stick duration for a contact cycle after the first observation window and the corresponding average contact stick durations for the one or more additional observation windows.