A power distribution monitoring system is provided that can include a number of features. The system can include a plurality of monitoring devices configured to attach to individual conductors on a power grid distribution network. In some embodiments, a monitoring device is disposed on each conductor of a three-phase network and utilizes a split-core transformer to harvest energy from the conductors. The monitoring devices can be configured to harvest energy from the AC power grid and saturate the magnetic core of the transformer in the event of a fault condition or when harvested power is not needed. Methods of installing and using the monitoring devices are also provided.

Embodiments of the disclosure include a fault current limiter having a first current splitting device including a primary winding and secondary winding wound around a first core, and a second current splitting device including a primary winding and a secondary winding wound around a second core. The fault current limiter may further include a fault current limiter module (e.g., a switching module) electrically connected in series between the secondary winding of the first current splitting device and the secondary winding of the second current splitting device. The fault current limiter may further include a second fault current limiter module electrically connected in series with the secondary winding of the second current splitting device. By splitting the fault current limiter into parts with fault current limiter modules interspersed between the windings, the fault current limiter may be to be built with less insulation between the windings.

The present invention provides topologies of phase-controlled IGBT bridge type and GTO bridge type Fault Current Limiter (FCL), which allow the precise limitation of fault currents to the desired values and can keep these values constant despite variations (dynamic behavior) of the fault currents. According to an embodiment of the invention, the topologies enable to use a phase control approach for optimal firing angles calculation. This control approach can be used in the proposed FCL topologies and other controlled bridge topologies such as SCRs bridge, GTO bridge, and IGBT/IGCT/Mosfet bridge topologies.

A device for limiting a fault current for a generator, in particular of a wind turbine is provided. A first frame is made of a ferromagnetic material, wherein the first frame comprises a first frame section and a further first frame section, wherein a first gap is formed between the first frame section and the further first frame section. A first coil is wound around the first frame section, wherein the first coil is connectable to a first stator winding of a stator of the generator. A further first coil is wound around the further first frame section, wherein the further first coil is connectable to an electronic device. A first permanent magnet element is arranged inside the first gap. The first frame section and the further first frame section are formed with respect to each other such that an electromagnetic interaction between the first coil and the first permanent magnet element and the further first coil and the first permanent magnet element is provided.

The present invention provides a fault current limiter apparatus comprising: a fault current limiter including: a magnetically saturable core, at least one AC coil wound on at least a portion of the magnetically saturable core, and a magnetic biasing arrangement for magnetically biasing at least a portion of the magnetically saturable core; a source terminal for electrically connecting the fault current limiter to a power source, and a load terminal for electrically connecting the fault current limiter to a load, wherein the at least one AC coil of the fault current limiter is electrically connected between the source and load terminals, and wherein the fault current limiter has a first inductance in normal conditions and a second inductance in fault conditions; a first capacitance electrically connected between the source and load terminals, wherein the first capacitance is electrically connected in series with the fault current limiter, and wherein the first capacitance has a capacitance that is arranged to have a reactance value that compensates for at least some of the first inductance.

Described herein are fault current limiters including an input terminal for electrically connecting to a power source that provides a load current, and an output terminal for electrically connecting with a load circuit that draws the load current. The fault current limiters include a magnetically saturable core including at least one coil receiving limb disposed intermediate at least two return limbs, wherein the limbs longitudinally extend between at least two yokes, and wherein the at least two yokes and the at least two return limbs define at least a portion of one or more magnetic flux return paths for the at least one coil receiving limb. The fault current limiters further includes at least one AC coil disposed about the at least one coil receiving limb for carrying the load current between the input terminal and the output terminal. The fault current limiters also includes a magnetic biasing system for magnetically biasing the core such that, in response to one or more characteristics of the load current, the at least one AC coil moves from a low impedance state to a high impedance state.

A fault current limiter (FCL) includes at least one magnetisable core member and at least one AC magnetomotive force source configured to generate a varying magnetic flux in at least a portion of the at least one magnetisable core member. At least one static magnetomotive force source is positioned to provide a magnetic circuit within at least part of the at least one magnetisable core member and the AC magnetomotive force source and the static magnetomotive force source are relatively positioned to be orthogonal to each other. Typically the static magnetomotive force source may be a permanent magnet and the AC magnetomotive force source configured to generate a varying magnetic flux in both of first and second spaced core members.

A power distribution monitoring system is provided that can include a number of features. The system can include a plurality of monitoring devices configured to attach to individual conductors on a power grid distribution network. In some embodiments, a monitoring device is disposed on each conductor of a three-phase network and utilizes a split-core transformer to harvest energy from the conductors. The monitoring devices can be configured to harvest energy from the AC power grid and saturate the magnetic core of the transformer in the event of a fault condition or when harvested power is not needed. Methods of installing and using the monitoring devices are also provided.

A fault current limiter (FCL) includes at least one magnetisable core member and at least one AC magnetomotive force source configured to generate a varying magnetic flux in at least a portion of the at least one magnetisable core member. At least one static magnetomotive force source is positioned to provide a magnetic circuit within at least part of the at least one magnetisable core member and the AC magnetomotive force source and the static magnetomotive force source are relatively positioned to be orthogonal to each other. Typically the static magnetomotive force source may be a permanent magnet and the AC magnetomotive force source configured to generate a varying magnetic flux in both of first and second spaced core members.

A method for reducing the inrush current of an inductive load, particularly a transformer, comprising the following steps: a) connecting a DC power source to the transformer for a time tc, to magnetize its magnetic core until saturation is reached, and connecting the transformer to the AC mains via an electromechanical switch, in an initially open position; b) disconnecting the transformer from the DC power source, the magnetic flux being reduced to its residual value; c) closing the electromechanical switch to complete the connection, this connection point being determined by the phase angle selected from the sinusoidal signal of the voltage power lines, in such a way that magnetic flux corresponding to the steady state voltage equals the residual magnetic flux that remains when the transformer is disconnected from the DC power source.