A T-type DC circuit breaker includes a main branch, a first commutation switch, a second commutation switch, and a bypass branch. The first commutation switch and the second commutation switch are arranged at both ends of the main branch, respectively. The bypass branch is connected in parallel with the main branch. The main branch includes at least one half-controlled power electronic component. The bypass branch includes a bypass capacitor and a bypass diode connected in series. Each of the first commutation switch and the second commutation switch includes at least one fully-controlled power electronic component. The first commutation switch is connected in parallel with a first surge arrester, and the second commutation switch is connected in parallel with a second surge arrester. The grounded branch is arranged between the main branch and the second commutation switch and is grounded or connected to the negative terminal of the load.

A low-voltage protective switching device includes: at least one outer conductor path from an outer conductor supply terminal of the low-voltage protective switching device to an outer conductor load terminal of the low-voltage protective switching device; a neutral conductor path from a neutral conductor terminal of the low-voltage protective switching device to a neutral conductor load terminal of the low-voltage protective switching device; a mechanical bypass switch disposed in the outer conductor path; a first semiconductor circuit arrangement of the low-voltage protective switching device connected parallel to the mechanical bypass switch; an electronic control unit; a current measuring arrangement disposed in the outer conductor path, the current measuring arrangement being connected with the electronic control unit; and a first mechanical disconnecting switch disposed in series to the first semiconductor circuit arrangement and in parallel to the mechanical bypass switch. The electronic control controls the mechanical bypass switch.

A digital device is provided. The digital device uses three states, including a ground (GND) state, a voltage (VDD) state, and a FLOAT state. On designing a chip, two storage units and a pad circuit are set inside; the pad circuit comprises a current limiter and two switches; and less ports contained are required than the conventional. That is, one port obtains three states. As comparing to the conventional having only two states, the present invention uses the port connected with two storage units in the pad circuit for obtaining the three states; a circuit featuring “pull up” and “pull down” is used to identify the state of connection of the port; and the port determines a plurality of definitions through the three states of GND, VDD and FLOAT. Thus, a pad is saved for reducing the space and cost of the chip.

A multi-circuit DC breaking system is proposed. According to an exemplary embodiment of the present technique, there may be an advantage that by combining current-limiting technology and multi-circuit breaking technology, a failure may be quickly detected, a magnitude of a fault current may be firstly limited, and a breaking operation is performed, in a range of various fault currents, by distributing the fault currents to some circuits of multi-circuits configured in parallel, thereby easily increasing the capacity thereof.

Circuits for providing overcurrent protection are disclosed herein. The circuits feature depletion mode MOSFETs connected to resistive elements, preferably, Positive Temperature Coefficient (PTC) devices, configured in such a way so that the voltage across the PTC device is the same as the gate-to-source voltage of the MOSFET. The circuit may further be configured using a TVS diode, for clamping the drain-to-source voltage of the MOSFET during the overcurrent events. Heat transfer between the MOSFET and the PTC device facilitates overcurrent protection. A two-terminal device including a depletion mode MOSFET, a PTC device, and a TVS diode may provide overcurrent protection to other circuits. A bidirectional circuit c including two MOSFETS disposed on either side of a PTC is also contemplated for AC voltage overcurrent protection.

A power supply system to provide power to a load connected between first and second connectors. The system includes a generator that produces an alternating current generator output and a rectifier that receives the alternating current generator output and converts it into a direct current output and provides the direct current (DC) output between the first and second connectors. The system also includes a filter connected to the rectifier and between the connectors and that smooths the DC output. The filter includes a midpoint configured to be connected to ground. The system also includes a fault clearing source connected to the first connector that provides a clearing voltage to the first connector when a ground fault occurs on the first connector.

A system includes a first circuit breaker comprising a first solid state switch, first mechanical contacts, and a current sensor structured to sense current flowing through the first circuit breaker, and a second circuit breaker electrically coupled to the first circuit breaker and being structured to interrupt current flowing to the first circuit breaker, wherein the first circuit breaker is structured to transmit, to the second circuit breaker, a request upon detecting a failure mode, and wherein the second circuit breaker is structured to interrupt current flowing to the first circuit breaker in response to receiving the request, and the first circuit breaker is further structured to open the first mechanical contacts when the current flowing through the first circuit breaker drops to a predetermined level.

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 switching apparatus includes first and second electric terminals, and first and second electric branches comprising one or more switching devices. The second electric branch is electrically connected in parallel with said first electric branch between said first and second electric terminals. The switching apparatus comprises a current blocking circuit adapted to block a current along said second branch. The current blocking circuit includes a first switching device of solid-state type and a first electronic circuit electrically connected in parallel to said first switching device of solid-state type. The switching apparatus further comprises a current limiting circuit adapted to limit a current flowing along said second electric branch. Said current limiting circuit is electrically connected in series with said current blocking circuit and it includes a second switching device of solid-state type and a second electronic circuit electrically connected in parallel to said second switching device of solid-state type.

A system for restricting power to a load to prevent engaging circuit protection device for an aircraft. The system includes an energy source of an aircraft. The system further includes a plurality of sensors configured to sense at least an electrical parameter of a load of the plurality of loads. The system further includes an aircraft controller configured to receive electrical parameter of a load of the plurality of loads from the plurality of sensors, compare the electrical parameter to at least a current allocation threshold, detect that the electrical parameter has reached the current allocation threshold, calculate a power reduction to the load, and reduce power from the at least an energy source to each load of the plurality of loads by the power reduction. The system further includes at least an electrical circuit of an aircraft, wherein the electrical circuit comprises a circuit protection device.