The present disclosure provides a protection assistance device of multiple circuit breakers in a low-voltage system, in which protection assistance in both directions from the upper side to the lower side or from the lower side to the upper side is possible, and the number of wires for protection assistance between multiple upper/lower circuit breakers can be minimized. The protection assistance device includes at least one upper low-voltage circuit breaker; at least one middle low-voltage circuit breaker; at least one lower low-voltage circuit breaker; and a communication line which makes a communication connection between the low-voltage circuit breakers, wherein the low-voltage circuit breakers comprise a control unit for, when a trip operation of automatically breaking a circuit is performed, transmitting a communication packet for reporting a trip operation state to at least one predetermined circuit breaker among the circuit breakers through the communication line.

An arcing fault recognition unit for an electric low-voltage circuit, includes at least one voltage sensor for periodically ascertaining electric voltage values in the electric circuit, the voltage sensor being connected to an analysis unit which is designed in such a way that an arcing fault recognition signal is output when a variation in the voltage over time exceeds a first threshold value or drops below a second threshold value.

An arcing fault recognition unit for an electric low-voltage circuit, includes at least one voltage sensor for periodically ascertaining electric voltage values in the electric circuit, the voltage sensor being connected to an analysis unit which is designed in such a way that an arcing fault recognition signal is output when a variation in the voltage over time exceeds a first threshold value or drops below a second threshold value.

A DC power distribution system has power sources, a DC power distribution bus with DC bus sections. The system has power switching assemblies to couple one of the DC bus sections to another and a system controller. An inverter is connected to one of the power switching assemblies to supply a consumer. The first and second terminals are electrically coupled to first and second bus sections. First and second semiconductor devices between the terminals control current flow and there is a current connection from each terminal to a power switching assembly controller for providing an indication of current. A control signal line is connected between the power switching assembly controller and each semiconductor device provides a signal to the semiconductor devices to control the current flow and an inverter coupler couples each current connection to the inverter. The inverter coupler has a feed from each current connection to the inverter.

A DC power distribution system has power sources, a DC power distribution bus with DC bus sections. The system has power switching assemblies to couple one of the DC bus sections to another and a system controller. An inverter is connected to one of the power switching assemblies to supply a consumer. The first and second terminals are electrically coupled to first and second bus sections. First and second semiconductor devices between the terminals control current flow and there is a current connection from each terminal to a power switching assembly controller for providing an indication of current. A control signal line is connected between the power switching assembly controller and each semiconductor device provides a signal to the semiconductor devices to control the current flow and an inverter coupler couples each current connection to the inverter. The inverter coupler has a feed from each current connection to the inverter.

In a control device, control circuit units are connected to separate circuit power sources and to separate grounds. Ground monitor circuits respectively have a first resistor with one end connected to a voltage source, a second resistor with one end connected to an input terminal of a corresponding control circuit unit, and a capacitor. Among the one end of the first resistor, an other end of the first resistor, and the other end of the second resistor, at least one is connected to the subject system, and at least one is connected to an other system, and the control circuit unit monitors a ground abnormality of the other system based on a terminal voltage of the input terminal to which the second resistor is connected.

In a control device, control circuit units are connected to separate circuit power sources and to separate grounds. Ground monitor circuits respectively have a first resistor with one end connected to a voltage source, a second resistor with one end connected to an input terminal of a corresponding control circuit unit, and a capacitor. Among the one end of the first resistor, an other end of the first resistor, and the other end of the second resistor, at least one is connected to the subject system, and at least one is connected to an other system, and the control circuit unit monitors a ground abnormality of the other system based on a terminal voltage of the input terminal to which the second resistor is connected.

A method of operating an electrical power distribution system including a plurality of circuit protection devices and an additional circuit protection device communicatively coupled by a communications network is described. The method includes transmitting, by each circuit protection device of the plurality of circuit protection devices, an electrical current communication to the communication network, the electrical current communication including an indication of an electrical current detected by the transmitting circuit protection device formatted according to a network communication protocol of the communication network. The additional circuit protection device receives the electrical current communications from the plurality of circuit protection devices and determines, based on the received electrical current communications, whether a ground fault condition exists in the electrical power distribution system.

A method of operating an electrical power distribution system including a plurality of circuit protection devices and an additional circuit protection device communicatively coupled by a communications network is described. The method includes transmitting, by each circuit protection device of the plurality of circuit protection devices, an electrical current communication to the communication network, the electrical current communication including an indication of an electrical current detected by the transmitting circuit protection device formatted according to a network communication protocol of the communication network. The additional circuit protection device receives the electrical current communications from the plurality of circuit protection devices and determines, based on the received electrical current communications, whether a ground fault condition exists in the electrical power distribution system.

Apparatuses and methods for passively monitoring the integrity of current sensing devices and associated circuitry in protective devices such as Ground Fault Circuit Interrupters and Arc Fault Circuit Interrupters are provided. A protection circuit interrupter employs a capacitively coupled noise signal obtained by an arrangement of one or both of the line side arms relative to a Rogowski coil. The noise signal is monitored while the line and load sides of a protective circuit interrupter are disconnected, and the connection of the line and load sides disabled if the noise signal fails to correlate sufficiently to a reference noise cycle. When the line and load sides are connected, the RMS value of the observed current signal is monitored such that the line and load sides are disconnected if the observed current signal fails to meet an RMS threshold. The observed current signal is otherwise compensated by subtracting the reference noise cycle prior to monitoring for the fault condition applicable to the protective device.