Abstract: An apparatus includes a core and a helical frame coaxial with a segment of the core and having first and second major surfaces on opposite sides of the helical frame and each normal to a surface of the segment. At least one helical coil conforms to at least one of the first and second major surfaces. In some embodiments, the at least one helical coil may include first and second helical coils conforming to respective ones of the first and second major surfaces.

Abstract: An apparatus includes a mechanical switch and a solid-state switch, such as a diamond switch or antiparallel-connected thyristor pair, coupled in series between an AC source and the load, such as a substation input transformer. The control circuit may be configured to connect the AC power source to the load by closing the mechanical switch and turning on the solid-state switch thereafter. The control circuit may be configured to interrupt a connection of the AC source to the load by turning off the solid-state switch and closing the mechanical switch thereafter. Operations of the switches may be coordinated with a fuse coupled in series with the solid-state switch to address different types of fault conditions.

Abstract: An apparatus includes a mechanical switch and a solid-state switch, such as a diamond switch or antiparallel-connected thyristor pair, coupled in series between an AC source and the load, such as a substation input transformer. The control circuit may be configured to connect the AC power source to the load by closing the mechanical switch and turning on the solid-state switch thereafter. The control circuit may be configured to interrupt a connection of the AC source to the load by turning off the solid-state switch and closing the mechanical switch thereafter. Operations of the switches may be coordinated with a fuse coupled in series with the solid-state switch to address different types of fault conditions.

Abstract: Voltage samples are collected for a source and loads connected thereto by an electrical network. Respective negative sequence voltage difference values are generated for respective source/load pairs from the voltage sample. A connection (e.g., a loose connection) in the electrical network is identified based on the generated negative sequence voltage difference values. The identified connection is reported to a user. Identifying a connection in the electrical network may include identifying at least one source/load pair having an associated negative sequence voltage difference value that meets a predetermined criterion and identifying the connection based on the identified at least one source/load pair. Identifying the connection may include identifying at least one source/load pair having an associated negative sequence voltage difference value with a magnitude falling outside of at least one range associated with the at least one source/load pair.

Abstract: An apparatus includes a power semiconductor switch, a driver circuit configured to drive a control terminal of the power semiconductor switch, and a control circuit configured to apply a control signal to the driver circuit responsive to a comparison of a reference voltage to a voltage at the control terminal of the semiconductor switch. In some embodiments, the power semiconductor switch may include a field effect transistor (FET), such as a wide bandgap silicon carbide (SiC) MOSFET. The control terminal may include a gate terminal of the FET, and the voltage at the control terminal may include a gate voltage.

Abstract: An apparatus includes a mechanical switch and a solid-state switch, such as a diamond switch or antiparallel-connected thyristor pair, coupled in series between an AC source and the load, such as a substation input transformer. The control circuit may be configured to connect the AC power source to the load by closing the mechanical switch and turning on the solid-state switch thereafter. The control circuit may be configured to interrupt a connection of the AC source to the load by turning off the solid-state switch and closing the mechanical switch thereafter. Operations of the switches may be coordinated with a fuse coupled in series with the solid-state switch to address different types of fault conditions.

Abstract: An apparatus includes a power semiconductor switch, a driver circuit configured to drive a control terminal of the power semiconductor switch, and a control circuit configured to apply a control signal to the driver circuit responsive to a comparison of a reference voltage to a voltage at the control terminal of the semiconductor switch. In some embodiments, the power semiconductor switch may include a field effect transistor (FET), such as a wide bandgap silicon carbide (SiC) MOSFET. The control terminal may include a gate terminal of the FET, and the voltage at the control terminal may include a gate voltage.

Abstract: An apparatus includes a plurality of parallel-connected semiconductor switches (e.g., wide bandgap transistors) and a plurality of driver circuits having outputs configured to be coupled to control terminals of respective ones of the plurality of semiconductor switches and configured to drive the parallel-connected semiconductor switches responsive to a common switch state control signal. The apparatus further includes a control circuit configured to sense respective states of respective ones of the parallel-connected semiconductor switches and to control respective ones of the driver circuits responsive to respective ones of the sensed states.

Abstract: An apparatus includes a housing having a gas-insulated compartment and a non-gas-insulated receptacle therein. The receptacle is disposed adjacent to the gas-insulated compartment and configured for removable insertion of a circuit interrupter assembly therein. A bus is disposed in the gas-insulated compartment, and a contact is disposed in the receptacle, electrically coupled to the bus in the gas-insulated compartment and configured to mate with a terminal of the circuit interrupter assembly when the circuit interrupter assembly is installed in the receptacle. The receptacle may be configured for insertion of an insulation-encapsulated circuit interrupter pole unit and the apparatus may include at least one flexible insulation member attached to a side wall of the receptacle and configured to engage a sidewall of the pole unit.

Abstract: An apparatus includes a housing having a gas-insulated compartment and a non-gas-insulated receptacle therein. The receptacle is disposed adjacent to the gas-insulated compartment and configured for removable insertion of a circuit interrupter assembly therein. A bus is disposed in the gas-insulated compartment, and a contact is disposed in the receptacle, electrically coupled to the bus in the gas-insulated compartment and configured to mate with a terminal of the circuit interrupter assembly when the circuit interrupter assembly is installed in the receptacle. The receptacle may be configured for insertion of an insulation-encapsulated circuit interrupter pole unit and the apparatus may include at least one flexible insulation member attached to a side wall of the receptacle and configured to engage a sidewall of the pole unit.