Device for detecting superconductor quenching and application to a superconducting current limiter

A current limiter for connection into an electrical line in series with a circuit breaker having a small interrupting capacity, said current limiter comprising a cryostat housing a superconducting element consisting of two identical superconductor coils, wound coaxially in opposite directions, said coils being arranged in parallel, and said coils having ends respectively coupled to mutually insulated conductors which extend to the outside of the cryostat, said insulated conductors constituting the primary of a current transformer comprising a magnetic toroidal core through which said insulated conductors pass carrying currents flowing in opposite directions, said toroidal core further comprising a secondary winding having terminals across which a first signal is generated representative of the difference between the values of the currents in said conductors.

A current limiter for connection into an electrical line in series with a circuit breaker having a small interrupting capacity, said current limiter comprising a cryostat housing a superconducting element consisting of two identical superconductor coils, wound coaxially in opposite directions, said coils being arranged in parallel, said coils having ends coupled respectively to mutually insulated conductors which extend to the outside of the cryostat, said insulated conductors being coupled to said means for detecting a difference of intensity of the current flowing in said insulated conductors comprising an optical fiber supplied from a source of polarized light, wound several times around said insulated conductors and said insulated conductors being arranged so that their currents flow in opposite directions therein, and an analyzer for picking up the light leaving the optical fiber.

A current limiter for connection into an electrical line in series with a circuit breaker having a small interrupting capacity, said current limiter comprising a cryostat housing a superconducting element consisting of two identical superconductor coils, wound coaxially in opposite directions, said coils being arranged in parallel, said coils having ends respectively coupled to mutually insulated conductors which extend to the outside of the cryostat, said insulated conductors being coupled to means for detecting a difference of intensity of current passing therethrough comprising a Faraday rotator through which said conductors, arranged so that their currents flow in opposite directions, pass, means for connecting said Faraday rotator to a first optical fiber supplied from a light source and to a second optical fiber connected to an analyzer.

A current limiter for connection into an electrical line in series with a circuit breaker having a small interrupting capacity, said current limiter comprising a cryostat housing a superconducting element consisting of two identical superconductor coils, wound coaxially in opposite directions, said coils being arranged in parallel, said coils having ends coupled respectively to mutually insulated conductors which extend to the outside of the cryostat, said insulated conductors being coupled to means for detecting a difference of intensity comprising a Rogowski coil through which said conductors, arranged so that the current flows in the opposite direction, pass, and said Rogowski coil being operatively associated with an electronic signal processing circuit.