Asea Brown Boveri Ab

Nils-Johan Bergsjo

Lars Liljestrand

Birger Drugge

Emile Schreurs

A fault current limiter according to the invention comprises a contact device (K) to the contacts of which is connected a resistor/inductor combination comprising a series connection of a first (R1) and a second (R2) resistor as well as a third resistor/inductor (R3) connected in parallel with the series-connected resistors. The second resistor consists of a resistor with superconducting properties, dimensioned such that the change from superconducting to normally-conducting state occurs when the critical current density of the resistor is attained.

Fault current limiter

A current limiter according to the invention has two resistors, the first one consisting of a thin layer of a material which may become superconducting and the second one is a resistance layer applied on first resistor, the latter resistor layer being dimensioned such that its resistance becomes considerably lower than the resistance of the superconducting layer when it is not superconducting, however with a resistance of such a magnitude that, in the current circuit in question, it limits the current to a permissible value. For mechanical support of the resistors, an insulator is included in the current limiter, and the superconducting material is applied on insulator. The resistors and the insulator are arranged immersed into a cryotank.

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Vaster.ang.s, Sweden

Nils-Johan Bergsjo