A disconnection device for a high-voltage electrical system of a motor vehicle for disconnecting a high-voltage line of the high-voltage electrical system, includes an overcurrent protection apparatus; a first disconnecting unit which is made of a first actuatable disconnecting unit, the first disconnecting unit being designed to interrupt a current flow over the first disconnecting unit in the activated state; a second disconnecting unit which is made of a second actuatable disconnecting unit and the overcurrent protection apparatus, the second disconnecting unit being designed to conduct an overcurrent to the overcurrent protection apparatus which interrupts the current flow over the second disconnecting unit in the activated state; and a control unit which is designed to activate at least the second disconnecting unit in the event of an overcurrent and to activate at least the first disconnecting unit in the event of an overcurrent-independent event in order to separate the high-voltage line.

A protective device includes a first fuse circuit, an overvoltage protection circuit, and a second fuse circuit. The first fuse circuit prevents a flow of a line current from a voltage terminal to the electrical load when the line current reaches a first nominal current. The overvoltage protection circuit is connected downstream of the first fuse circuit and upstream of the electrical load, and is adapted to electrically connect two poles of the voltage terminal when a voltage at the voltage terminal reaches a first voltage limit to force the line current to the first nominal current such that the first fuse circuit is triggered. The second fuse circuit is connected downstream of the overvoltage protection circuit and upstream of the electrical load, and prevents flow of the line current when the line current reaches a second nominal current, wherein the second nominal current is based on the electrical load.

A protective device includes a first fuse circuit, an overvoltage protection circuit, and a second fuse circuit. The first fuse circuit interrupts a flow of a line current from a voltage terminal to the electrical load when an intensity of the line current reaches a first current intensity limit value. The overvoltage protection circuit electrically connects poles of the voltage terminal when a first voltage limit value of a voltage is reached on the first fuse circuit to force the line current to reach the first current intensity limit value. The second fuse circuit activates the overvoltage protection circuit when a second voltage limit value of a voltage on the second fuse circuit is reached to electrically connect the poles of the voltage terminal. The second voltage limit value is based at least in part on a nominal voltage of the electrical load.

Provided is a nano grid protection device for a nano grid including a distributed power supply, a large power grid including the nano grid protection device, and a method for controlling the nano grid protection device. In an embodiment, the nano grid is connected with a bus through the nano grid protection device and a main grid is connected with the bus through a main grid protection device. In an embodiment, the nano grid protection device includes: a signal unit, configured to detect and send current information passing through the nano grid protection device, the current information including the magnitude and direction of the current; a controller, configured to determine, based upon the received current information, whether to send a trip signal or not; and an execution mechanism, configured to execute a trip operation of the nano grid protection device upon receiving the trip signal.

A load center comprises a common instantaneous tripping unit that works on a principle of solid state switching. The load center further comprises a plurality of branches of branch circuit breakers each of which is coupled to the common instantaneous tripping unit via a corresponding high power connection and a corresponding low power connection such that the common instantaneous tripping unit feeds the plurality of branches at the same time. The common instantaneous tripping unit interrupts a short circuit fault in an interruption time which is significantly reduced thus reducing or eliminating chances for a personal injury during the short circuit fault.

A load center comprises a common instantaneous tripping unit that works on a principle of solid state switching. The load center further comprises a plurality of branches of branch circuit breakers each of which is coupled to the common instantaneous tripping unit via a corresponding high power connection and a corresponding low power connection such that the common instantaneous tripping unit feeds the plurality of branches at the same time. The common instantaneous tripping unit interrupts a short circuit fault in an interruption time which is significantly reduced thus reducing or eliminating chances for a personal injury during the short circuit fault.

A motor control system includes a motor switching assembly comprising a power converter positioned on a converter path, a first relay positioned on the converter path upstream of the power converter, a second relay positioned on a bypass path that is in parallel with the converter path, and a solid-state switching unit positioned upstream from the converter path and the bypass path. The motor control system also includes a control system that controls operation of the motor switching assembly, with the control system programmed to operate the solid-state switching unit in one of a conducting mode, a non-conducting mode, and a ramping mode, so as to selectively control and condition power flow therethrough. The control system is also programmed to control switching of the first and second relays between open and closed positions to selectively route power along the converter path or the bypass path.

A motor control system includes a motor switching assembly comprising a power converter positioned on a converter path, a first relay positioned on the converter path upstream of the power converter, a second relay positioned on a bypass path that is in parallel with the converter path, and a solid-state switching unit positioned upstream from the converter path and the bypass path. The motor control system also includes a control system that controls operation of the motor switching assembly, with the control system programmed to operate the solid-state switching unit in one of a conducting mode, a non-conducting mode, and a ramping mode, so as to selectively control and condition power flow therethrough. The control system is also programmed to control switching of the first and second relays between open and closed positions to selectively route power along the converter path or the bypass path.

The semiconductor circuit breaker includes a semiconductor switch unit connected to an AC circuit, and a phase control unit that controls conduction and non-conduction of the semiconductor switch unit by the control signal. The phase control unit includes an accident detection unit to detect an accident based on a current detected from the AC circuit, a zero point detection unit to detect a current zero point based on the current detected from the AC circuit, and a control signal output unit to output the control signal for setting the semiconductor switch unit to be non-conductive when the accident detection unit detects the accident or when the zero point detection unit detects the current zero point in response to a command to cut off the current.

A protective device includes a first fuse circuit, an overvoltage protection circuit, and a second fuse circuit. The first fuse circuit prevents a flow of a line current from a voltage terminal to the electrical load when the line current reaches a first nominal current. The overvoltage protection circuit is connected downstream of the first fuse circuit and upstream of the electrical load, and is adapted to electrically connect two poles of the voltage terminal when a voltage at the voltage terminal reaches a first voltage limit to force the line current to the first nominal current such that the first fuse circuit is triggered. The second fuse circuit is connected downstream of the overvoltage protection circuit and upstream of the electrical load, and prevents flow of the line current when the line current reaches a second nominal current, wherein the second nominal current is based on the electrical load.