A system for transient over voltage protection of a three-phase transformer. Two surge arresters are series connected across each winding of the transformer and the center point connection of the two surge arresters is electrically connected to a middle location of the winding. Three additional surge arresters are electrically connected from each phase to ground in the case of either a delta or Y connected transformer; and/or connected from a neutral point to ground in the case of a Y connected transformer. The system allows for all of the surge arresters to be packaged as an integrated surge arrester system to minimize induced transient over voltages and high stresses on the transformer winding due to internal resonances.

A common mode filter is manufactured to include a coil part including an insulation layer and a conductor pattern formed in the insulation layer; and a magnetic substrate coupled to one surface or both surfaces of the coil part. The magnetic substrate includes: an electrostatic absorbing layer made of an electrostatic absorbing material; a magnetic layer provided on one surface or both surfaces of the electrostatic absorbing layer and made of a magnetic material; and an electrode provided between the magnetic layer and the electrostatic absorbing layer and made of a conductive material. Therefore, common mode filter may maintain high efficiency characteristics while preventing an electrostatic discharge phenomenon.

A plurality of windings each including an electric wire portion and a first insulating coating that coats the electric wire portion. A plurality of electrostatic shields each including a conductor and a second insulating coating that coats the conductor. A stationary induction apparatus satisfies at least one positional relationship among: a relationship in which an outer peripheral end of the conductor in each of the electrostatic shields is located inside an outer peripheral end of the electric wire portion of an adjacent winding among the windings, the adjacent winding being adjacent to the electrostatic shield in the direction extending along the central axis; and a relationship in which an inner peripheral end of the conductor in each of the electrostatic shields is located outside an inner peripheral end of the electric wire portion of the adjacent winding.

Each of a plurality of electrostatic shields includes an insulator portion and a conductor portion. The conductor portion includes a flat portion formed in an annular shape and a pair of protruding portions. The insulator portion is provided with a first housing portion housing the flat portion and a pair of second housing portions each housing a corresponding one of the pair of protruding portions. Each of the pair of protruding portions includes: a protruding end portion located along an inner surface of a corresponding one of the pair of second housing portions, and a center portion located adjacent to the protruding end portion. In each of the pair of protruding portions, the protruding end portion and the center portion are electrically connected to each other and are equal in electric potential to each other.

Each of a plurality of electrostatic shields includes an insulator portion and a conductor portion. The conductor portion includes a flat portion formed in an annular shape and a pair of protruding portions. The insulator portion is provided with a first housing portion housing the flat portion and a pair of second housing portions each housing a corresponding one of the pair of protruding portions. Each of the pair of protruding portions includes: a protruding end portion located along an inner surface of a corresponding one of the pair of second housing portions, and a center portion located adjacent to the protruding end portion. In each of the pair of protruding portions, the protruding end portion and the center portion are electrically connected to each other and are equal in electric potential to each other.

A seawater-based high resistance grounding device for a subsea transformer includes an insulated pipe mounted to the outside of the transformer so as to be exposed to seawater. The insulated pipe has two or more cylindrical metallic electrodes electrically connected to ground and to the neutral node of the secondary transformer windings. The volume of seawater within the pipe and between the electrodes provides one or more high resistance ground paths for protection of the transformer.

In a common-mode choke coil, first annular conductors are helically defined from the lower layer to the upper layer, and first annular conductors are helically defined from the upper layer to the lower layer. Further, second annular conductors are helically defined from the lower layer to the upper layer, and second annular conductors are helically defined from the upper layer to the lower layer. The first annular conductors and the second annular conductors are disposed alternately in a lamination direction. The first annular conductors and the second annular conductors are disposed such that substantial portions of the annular conductors adjacent to each other in the layer direction do not overlap in a planar view. This structure achieves a compact common-mode choke coil with which the loss of normal-mode signals is small, and which is highly capable of removing common-mode noise.

A surge protective network signal processing circuit assembly includes a network chip, a network connector and a processing circuit including a plurality of two-wire channels electrically connected in parallel between the network chip and the network connector and a plurality of signal coupling capacitors respectively mounted in the two-wire channels and electrically connected in parallel and grounded for discharging instantaneous high voltage surges.

A surge blocking inductor. In one embodiment, the surge blocking inductor includes a core; a first winding wound about the core in a first direction; and a second winding wound about the core in a second direction, wherein the first winding and the second winding are magnetically independent when the core is in a non-saturated state, and wherein the first winding and the second winding are coupled magnetically when the core is in a saturated state.

The invention relates to a docking module (22) for a current transformer (10) comprising:

an electronic circuit (12) and

at least one electric connecting element (28.3) for electrically coupling the circuit (12) to the current transformer (10) and for docking the docking module (22) onto the current transformer (10).