A hybrid switch assembly for use in a circuit interrupter, the hybrid switch assembly including an input, an output, separable contacts electrically connected between the input and the output, a solid state switching circuit electrically connected between the input and the output and in parallel with the separable contacts, and a fuse electrically connected in series with the solid state switching circuit. The solid state switching circuit is structured to turn on and allow current to flow through it between the input and the output for a predetermined amount of time after the separable contacts separate.

In an electrical distribution system including a solid-state circuit breaker (SSCB) and one or more downstream mechanical circuit breakers (CBs), a solid-state switching device in the SSCB is repeatedly switched ON and OFF during a short circuit event, to reduce a root-mean-square (RMS) value of the short circuit current. The resulting pulsed short circuit current is regulated in a hysteresis control loop, to limit the RMS to a value low enough to prevent the SSCB from tripping prematurely but high enough to allow one of the downstream mechanical CBs to trip and isolate the short circuit. Pulsing is allowed to continue for a maximum short circuit pulsing time. Only if none of the downstream mechanical CBs is able to trip to isolate the short circuit within the maximum short circuit pulsing time is the SSCB allowed to trip.

A system and method are provided to detect a fault on a circuit. A current sensor is provided for sensing current on at least one line conductor and/or a neutral conductor on a circuit, and a switch is operated between at least first and second positions to selectively control a signal pathway on the at least one line conductor or the neutral conductor in relations to the sensor. The sensor performs a first current measurement corresponding to current across one conductor from the at least one line conductor and the neutral conductor in the first position, and a second current measurement corresponding to a current balance or imbalance between the conductors in the second position. The current sensor outputs the first current measurement for detecting an arc fault in the first position, or the second current measurement for detecting a ground fault in the second position.

A system may include a power supply that generates a first voltage. The power supply may couple upstream from an electrical load. The electrical load may operate based at least in part on the first voltage. In some cases, a solid-state circuit breaker may be coupled between the power supply and the electrical load. Furthermore, a control system may be communicatively coupled to the power supply, the electrical load, and the solid-state circuit breaker. The control system may receive an operational status from the solid-state circuit breaker and may update a visualization rendered on a graphical user interface based at least in part on the operational status. The operational status may indicate an operation of the solid-state circuit breaker coupling the power supply to the electrical load.

In a circuit breaker arrangement, this disclosure describes a method and circuit design enables a current transformer to be used to detect ground faults in circuit breakers (such as a main-tie-main circuit breakers) that have been designed to receive signals from Rogowski coils.

A trip apparatus for a circuit interruption device that comprises a coil operatively connectable to a circuit interruption device. The coil is configured to selectively operate the circuit interruption device to interrupt when a current flowing through the circuit interruption device exceeds a threshold. The trip apparatus also includes a current measuring device configured to selectively measure a coil current flowing through the coil to determine a measured coil current signal. In addition, the trip apparatus includes a monitoring device configured to determine the derivative of the measured coil current signal and to perform a correlation of the derivative of the measured coil current signal and a reference derivative of a reference coil current signal to determine a correlation output. The monitoring device is further configured to compare the correlation output with a reference correlation threshold to determine whether an operating condition of the coil is normal or abnormal.

An electrical switch for switching an electric current is disclosed. The electrical switch includes an electronic trip unit, embodied in a bipartite fashion. A first part of the trip unit is fixedly connected to the electrical switch and includes protection functions of the electrical switch. A second part of the trip unit is embodied mountably and detachably on the electrical switch and defines the protection functions enabled for the customer.

A switching device includes: an electronic trip unit; an actuator; a switching mechanism connected via the actuator to the electronic trip unit; a stationary contact; a mobile contact, which is coupled to the switching mechanism; and an alarm module. The alarm module includes: a first, a second, and a third connector; a first relay having a first contact which is connected to the first connector and having a second contact which is connected to the second connector; a second relay with a first contact which is connected to the third connector; and a control unit which is coupled on an output side to a control side of the first relay and to a control side of the second relay, and on the input side to the electronic trip unit.

A circuit-breaker includes an electronic trip unit, which initiates an interruption or reduction of the current flow in a low-voltage circuit when current or current-time limits are exceeded in the low-voltage circuit. The electronic trip unit includes at least two processors that independently check whether current or current-time limits are being exceeded. A test signal is fed to the circuit-breaker via a first communication interface, which is fed to one of the two processors during operation so that a test of the circuit-breaker is carried out during operation, while at the same time an active protection is provided with regard to the exceeding of current or current-time limits.

An embodiment of the invention relates to a method for ground fault detection for low-voltage three-phase AC circuits having a neutral conductor, in which first to fourth analog current signals of the first to third phase conductors and of the neutral conductor of the three-phase AC circuit are ascertained that each contain the level or an equivalent of the level of the current. The analog current signals are time-division multiplexed, subjected to a/d conversion, and a sequence of time-division-multiplexed first to fourth digital current values present in first to fourth successive time frames form first to fourth current signals. Three of the four digital current signals are interpolated to ascertain interpolated current values. The current value of the time frame of the uninterpolated current signal and the interpolated current values for the time frame of the uninterpolated current signal are used for discovering the ground fault.