A switching apparatus for electric power distribution grids including: a withdrawable first switching unit having one or more first electric poles; a withdrawable second switching unit having one or more second electric poles and electrically connected ins series with said first switching unit; and a controller implementing control strategies directed to increase the safety of the withdrawal manoeuvres of said first and second switching units.

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 fusible switch disconnect device includes a housing adapted to receive at least one fuse therein, and a switchable contact for connecting the fuse to circuitry. A tripping mechanism and control circuitry are provided to move the switchable contact to an open position in response to a predetermined electrical condition.

A design of a protection relay, and interface with an operator of a protection relay, are disclosed. The protection relay can include a base relay for measurement of line current and for generation of a trip signal, a base Human Machine Interface (HMI) for user specifying of a base setting of an operating parameter of the protection relay, and an optionally active Human Machine Interface (HMI) unit having a processing unit to manage plural activities with controlled power consumption.

A circuit breaker with improved trip unit fixation is disclosed. Another circuit breaker and a system also perform the functions of the circuit breaker. A circuit breaker includes a frame and a trip unit mounted in the frame. The trip unit includes a terminal for securing a wire to the trip unit. One of a wall of the frame and the trip unit include a protrusion and the wall of the frame or the trip unit without the protrusion includes an opening. The protrusion conforms to the opening and the protrusion and opening are positioned to oppose movement of the trip unit in a direction of a force resulting from securing the wire in the terminal.

A circuit breaker with an integrated motorized racking mechanism, automatically provides electrical power to the racking motor when the breaker is inserted into a breaker compartment. The racking motor remains powered when the breaker is in either a disconnected position, a testing position, or a fully connected position. A racking power plug mounted within the circuit breaker conducts electrical power to the racking motor by automatically connecting to a stationary racking power receptacle mounted in the breaker compartment, and remains connected as the circuit breaker moves through the breaker compartment during the racking operation. A control power plug is mounted in the circuit breaker to connect to a stationary control power receptacle mounted in the breaker compartment and to conduct control power to control circuits in the circuit breaker after the racking motor has completed racking the circuit breaker into the connected position in the breaker compartment.

A solid state circuit breaker comprising, includes a first switch unit including, a first switch configured to be connected to a first terminal, a second switch connected to the first switch configured to be connected to a second terminal, a third switch connected to the second switch and configured to be connected to the second terminal, a fourth switch connected to the first switch and configured to be connected to the first terminal, and a fifth switch joining a connection of the first switch and the second switch to the connection of the third switch and the fourth switch.

A system includes an electrical apparatus configured to monitor or control one or more aspects of an electrical power distribution network; and a control system including more than one electronic processor, where the electronic processors are configured to cause the control system to interact with the electrical apparatus, an interaction between the control system and the electrical apparatus including one or more of the control system providing information to the electrical apparatus and the control system receiving information from the electrical apparatus, and if some of the electronic processors are unable to cause the control system to interact with the electrical apparatus, at least one of the other electronic processors is able to cause the control system to interact with the apparatus.

A fusible switch disconnect device includes a housing adapted to receive at least one fuse therein, and a switchable contact for connecting the fuse to circuitry. A current detecting element, a tripping mechanism, and control circuitry are provided to move the switchable contact to an open position in response to predetermined electrical current conditions in the 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.