A system includes a current transformer including: a primary coil, and a secondary coil including at least two taps; a tap selection circuit; a current measurement apparatus configured to produce an indication of an amount of current flowing in the secondary coil; a power supply electrically connected to a first one of the taps, the power supply configured to receive electrical power from the first one of the taps; and a controller coupled to the power supply and the current measurement apparatus, the controller configured to receive electrical power from the power supply and to control the tap selection circuit based on the indication of an amount of current in the secondary coil.

A system includes a current transformer including: a primary coil, and a secondary coil including at least two taps; a tap selection circuit; a current measurement apparatus configured to produce an indication of an amount of current flowing in the secondary coil; a power supply electrically connected to a first one of the taps, the power supply configured to receive electrical power from the first one of the taps; and a controller coupled to the power supply and the current measurement apparatus, the controller configured to receive electrical power from the power supply and to control the tap selection circuit based on the indication of an amount of current in the secondary coil.

An external switch actuator includes: a guide tube having a first end and a second end, the first end configured to be attached to a door of a compartment in substantial alignment with both a hole in the door and a switch actuator within the compartment, and the second end configured to be disposed within an interior of the compartment and separated from the switch actuator by a gap when the door is closed; a coupling shaft configured to be operably placed within the guide tube, the coupling shaft having an electrical insulator disposed between an actuator side adapter and a switch side adapter, and a length equal to or greater than a distance between the switch actuator and the hole in the door when the door is closed.

A transformer assembly for electric grids including: an electric transformer including a magnetic core, a first side including one or more first windings enchained with said magnetic core and adapted to be electrically connected to a first grid section and a second side including one or more second windings enchained with said magnetic core and adapted to be electrically connected to a second grid section; a tap changer operatively associated with said electric transformer to vary the number of turns enchained with said magnetic core for said first windings; a control unit to: acquire input data indicative of an electrical connectivity condition of said second grid section with said second windings; determine whether said transformer is in a load condition or in a no-load condition; and, in a no-load condition, command said tap changer to set a maximum available number of turns for said first windings.

An inductive power device with variable active winding size, comprises first circuitry, multiple winding segments and switching circuitry operable to connect selectable combinations of the winding segments serially to the first circuitry via taps. At least two of the winding segments are of unequal size, wherein said at least two winding segments are provided as sequential portions of a total winding magnetically coupled to an opposite winding, wherein the winding segments have uniform polarity with respect to said magnetic coupling. The switching circuitry comprises an arrangement of semiconductor switches which are operable to include or exclude each winding segment independently. In an embodiment, the arrangement of switches comprises at least one half-bridge structure.

A structure for wireless communication having a plurality of conductor layers, an insulator layer separating each of the conductor layers, and at least one connector connecting two of the conductor layers wherein an electrical resistance is reduced when an electrical signal is induced in the resonator at a predetermined frequency. The structure is capable of transmitting or receiving electrical energy and/or data at various near and far field magnetic coupling frequencies.

A structure for wireless communication having a plurality of conductor layers, an insulator layer separating each of the conductor layers, and at least one connector connecting two of the conductor layers wherein an electrical resistance is reduced when an electrical signal is induced in the resonator at a predetermined frequency. The structure is capable of transmitting or receiving electrical energy and/or data at various near and far field magnetic coupling frequencies.

A system includes conductive windings extending around a magnetic core and impedance-varying windings extending around the magnetic core. The impedance-varying windings include positive windings and negative windings. The conductive windings and the impedance-varying windings conduct electric current around the magnetic core. The system includes a first impedance tap changer that is electrically coupled with the positive windings of the impedance-varying windings and a second impedance tap changer electrically coupled with the negative windings of the impedance-varying windings. A controller controls the first impedance tap changer and the second impedance tap changer to change an impedance of the system by changing which portion of the positive windings and which portion of the negative windings are conductively coupled with the conductive windings, and which portion of the positive windings and which portion of the negative windings are disconnected from the conductive windings.

An on-load tap-changer uninterruptedly operates a diverter switch between different winding taps of a tap-changing transformer. The on-load tap-changer has an on-load tap-changer plate; a selector; and a diverter switch. The selector and the diverter switch are mounted on the on-load tap-changer plate.

An assembly for connection to a high-voltage system has multiple single-phase transformers each having a transformer tank which is filled with a fluid and in which a core with at least one winding is situated. At least some of the windings of the single-phase transformers are connected to one another, forming a neutral point. A short-circuit voltage curve or impedance of the assembly can be adapted to different requirements. The windings are each connected to the neutral point via a switchover unit and a choke winding. The choke winding has multiple tappings, and the switchover unit is configured to select the tapping via which the winding in question is connected to the neutral point.