Solid state and hybrid circuit protection devices include improved arc-less switching capability and overcurrent protection, improved terminal assemblies and improved thermal management features that reduce or eliminate ignition sources for hazardous environments. The solid state and hybrid circuit protection devices are ignition protected and avoid possible explosions and therefore obviate a need for conventional explosion-proof enclosures to ensure safe operation of an electrical power system in a hazardous location.

A circuit breaker includes: at least one external conductor section from an external conductor supply terminal of the circuit breaker to an external conductor load terminal of the circuit breaker; and one neutral conductor section from a neutral conductor terminal of the circuit breaker to a neutral conductor load terminal of the circuit breaker. A mechanical bypass switch is arranged in the at least one external conductor section. A semiconductor circuit arrangement of the circuit breaker, which semiconductor circuit arrangement comprises a four-quadrant switch, is connected in parallel with the bypass switch. A current measuring arrangement is arranged in the at least one external conductor section and is connected to an electronic control unit of the circuit breaker. The electronic control unit is configured to operate the bypass switch and the semiconductor circuit arrangement in a prespecifiable manner. A voltage-dependent resistor is arranged in parallel with the bypass switch.

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.

An isolation disconnect assembly for an insulated gate bipolar transistor assembly is provided. The isolation disconnect assembly includes a conductor assembly and a clinch joint magnetic actuator.

A disconnector device is connectable to pole-mounted equipment in a power grid. The disconnector device is activated in case of an overload condition, thereby disconnecting the pole-mounted equipment. The disconnector device comprises a passive radio device to be enabled via an incoming radio signal. The passive radio device, upon being enabled, transmits, in at least one state of the disconnector device, an indicator radio signal indicative of the respective state of the disconnector device, the state being one of an activated state and a deactivated state of the disconnector device.

A solid-state circuit breaker (SSCB) with self-diagnostic, self-maintenance, and self-protection capabilities includes: a power semiconductor device; an air gap disconnect unit connected in series with the power semiconductor device; a sense and drive circuit that switches the power semiconductor device OFF upon detecting a short circuit or overload of unacceptably long duration; and a microcontroller unit (MCU) that triggers the air gap disconnect unit to form an air gap and galvanically isolate an attached load, after the sense and drive circuit switches the power semiconductor device OFF. The MCU is further configured to monitor the operability of the air gap disconnect unit, the power semiconductor device, and other critical components of the SSCB and, when applicable, take corrective actions to prevent the SSCB and the connected load from being damaged or destroyed and/or to protect persons and the environment from being exposed to hazardous electrical conditions.

A circuit breaker includes a circuit breaker housing, an air-gap switch disposed within the housing, and a first visual indicator configured to provide an indication of an open state and a closed state of the air-gap switch. The first visual indicator includes a first window that is formed as part of the circuit breaker housing, and first and second indicator elements disposed within the circuit breaker housing. The first indicator element is configured to move into position behind the first window as the air-gap switch is placed into the open state and thereby provide a visual indication of the open state of the air-gap switch. The second indicator element is configured to move into position behind the first window as the air-gap switch is placed into the closed state and thereby provide a visual indication of the closed state of the air-gap switch.

A DC voltage switch includes a semiconductor-based electronically controllable switching device, a sensor provided upstream of the switching device for determining the DC voltage bus-side voltage level, a sensor provided downstream of the switching device for determining the DC voltage branch-side voltage level, a current sensor for determining current level and direction, a control device designed such that the direction and level of the current are determined, the flow of current is interrupted by the switching device when a first threshold value of the current level is exceeded, and when the first threshold value of the current level is exceeded in the reverse direction: the DC voltage bus-side voltage level is compared with the DC voltage branch-side voltage level, and the switching device is switched on upon a voltage difference being less than a voltage difference value.

A hybrid circuit breaker for interrupting a current in an electrical circuit line, the hybrid circuit breaker includes an input terminal for connection to a power line and an output terminal for connection to a DC system, a first solid state switching device connected to the input terminal, and a mechanical isolator relay arranged in series with the first solid state switching device and connected to the output terminal. The hybrid circuit breaker further includes a crowbar circuit electrically connected between the output terminal and ground or mid-pole, and a controller for controlling the first solid state switching device, the mechanical isolator relay and the crowbar circuit.

A direct current circuit breaker includes: a positive supply line between a positive input terminal and a positive output terminal; a negative supply line between a negative input terminal and a negative output terminal connecting a direct current load to a supply; a series connection of a first galvanic separation switch and a bypass switch in the positive supply line, and a second galvanic separation switch in the negative supply line; a semiconductor switch element connected parallel to the bypass switch; and a series connected inductor in the positive supply line. The first and second galvanic separation switch, the bypass switch, and the semiconductor switch element are controlled using a processing unit.