Superconductive fault current limiters
AssigneeGEC Alsthom SA
InventorFrancis James Mumford
Life of this patent
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Abstract
An inductive Superconductive Fault-Current Limiter (SCFCL) includes an iron core having a wound primary winding and a short-circuited superconductive secondary. The secondary remains superconductive up to a fault-current level in the primary, after which the superconductive secondary becomes resistive, the primary ampere-turns are not balanced, and the device becomes highly inductive, so limiting the fault-current. The fault-current threshold is increased without exceeding available critical superconductive current density levels and with a moderate superconductive coating thickness by using a stack of superconductive coated washers having a large radial extent compared to the coating thickness.
Claims12
A superconductive fault-current limiter, comprising:
- a primary fault-current winding, a secondary winding in the form of a superconductive cylinder having an axis, and a ferromagnetic circuit threading both primary and secondary windings, the primary and secondary windings being arranged to produce substantial cancellation of primary flux in the ferromagnetic circuit in the superconducting condition of the secondary winding, wherein the superconductive cylinder comprises a substrate coated with superconductive material, the substrate being of such form that at least sections of the superconductive coating extend laterally relative to the axis of the cylinder, said laterally extending sections forming short-circuit current paths around said cylinder axis.
A superconductive fault-current limiter, comprising:
- a primary fault-current winding, a secondary winding in the form of a superconductive cylinder, and a ferromagnetic circuit threading both primary and secondary windings, the primary and secondary windings being arranged to produce substantial cancellation of primary flux in the ferromagnetic circuit in the superconducting condition of the secondary winding, wherein the superconductive cylinder comprises a tubular substrate coated with superconductive material, said substrate comprising a stack of individual washer-like components coated with superconductive material on one or both faces and mounted on said tubular substrate.
Dependencies are inferred from the claim text.