Gate control of power semiconductor devices using reduced gate drivers is disclosed. A circuit breaker may include a multitude of transistors, such as insulated gate bipolar transistors (IGBTs), connected in series with one another. Each transistor may be connected to a respective gate resistor. Diodes may be connected between various gate resistors. One or more resistor-capacitor (RC) snubber circuits may be provided in parallel with one or more of the transistors. Likewise, one or more metal-oxide varistors (MOVs) may be connected in parallel to one or more of the transistors. A gate driver (e.g., a single gate drive) may be connected to the one or more diodes and an emitter of at least one of transistors.

A switching apparatus for an electric grid includes first and second electric terminals, each having first and second electric branches having a plurality of switching devices. The first electric branch includes a first switching device switchable between open and closed states, which is driven by a current flowing along said first switching device and without receiving an external control signal or an external power supply, said first switching device switching from said closed state to said open state, when the current flowing along said switching apparatus exceeds a corresponding predefined threshold value or when the changing rate of the current flowing along said switching apparatus exceeds a corresponding predefined threshold value or upon a combination of these two conditions. A second switching device is connected in series with the first switching device and is switchable between closed and open states upon receiving a corresponding input control signal.

A direct current circuit breaker comprises a mechanical relay in a first supply line configured to conduct electrical current during steady-state operation and an auxiliary relay assembly in parallel with the mechanical relay to define an auxiliary breaker path for conducting electrical current during transient operation of the circuit breaker. The auxiliary relay assembly comprises a power-semiconductor circuit configured for selective current conduction and for bidirectional current blocking when in a non-conductive state. There is also a controller configured to (i) activate the power-semiconductor circuit to conduct in response to a command signal to stop transfer of the electrical power, in order to provide a zero voltage condition under which the mechanical relay is to deactivate; (ii) deactivate the mechanical relay when current is being conducted through the auxiliary breaker path; and (iii) deactivate the power-semiconductor circuit after the mechanical relay is deactivated to stop the transfer of the power.

A current interrupting device includes: a current limiting element provided on a power supply path from a predetermined power supply to a load device, the current limiting element being configured to exhibit a current limiting action when current flowing the power supply path exceeds a first current threshold value; a current diversion path switch capable of switching on and off of an electric conduction of a current diversion path, the current diversion path switch being connected in parallel with the power supply path; and a controller configured to control on and off of the current diversion path switch, wherein, the controller is configured to: switch the current diversion path switch on from an off state when it is detected that current flowing the current limiting element is limited to a second current threshold value after the current flowing the current limiting element has exceeded the first current threshold value; and switch the current diversion path switch off again after a predetermined switched-on holding time has elapsed since the current diversion path switch has been switched on.

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.

A switch system includes a mechanical switch for switching electrical currents, the mechanical switch operating in one of a closed state and an open state; the system further including an actuator configured to change the state of the mechanical switch, wherein the actuator comprises a Thomson-coil system including a Thomson coil, and wherein the mechanical switch and the Thomson coil are electrically connected in series.

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 method of operating a Fault Current Limiter Circuit Breaker including a plurality of FLCB modules connected in series, including at least a first module and a second module. Each module includes a plurality of parallel component legs including a mechanical switch leg including a mechanical switch, a semiconductor switch leg including a semiconductor switch, and a Metal Oxide Varistor leg including a MOV. The method includes, when the FLBC is in an open configuration, obtaining an indication that the FLCB should be closed; in response to the obtained indication, closing the semiconductor switch of each of the modules; and, after the closing of the semiconductor switches and while the mechanical switch of the second module remains open, closing the mechanical switch of the first module.

A switch system includes a mechanical switch for electrical currents. The mechanical switch operates in a conductive state and in a non-conductive state. A first actuator is configured to change the state of the mechanical switch, wherein an actuation of the first actuator is based on a Thomson coil system. A second actuator is also configured to change the state of the mechanical switch and includes a loaded spring system locked by a latch system. Each of the first and second actuators is configured to change the state of the mechanical switch depending on a property of an electrical current passing through the mechanical switch.

A system including an arc flash sensor that detects an arc flash event and an arc flash mitigation device in communication with the sensor. The mitigation device includes a path of least resistance having a path input and a path output. The arc flash sensor is located downstream the output. The mitigation device includes an electro-mechanical switch between the input and the output and an actuator. The mitigation device also includes a bypass power switch device that includes a solid-state circuit interrupter and that conduct current between the input and the output in response to an open-circuit condition of the switch. A system controller is provided to generate a trigger to activate the actuator to generate the open-circuit condition of the switch, which causes the power switch device to interrupt a fault current associated with a fault event in response to detection of the arc flash event.