Superconducting AC current limiter equipped with quick-recoverable trigger coils.

摘要

In a superconducting AC (alternating current) current limiter (100), quenched trigger coil assembly (30) is quickly recovered to the superconductive state by minimizing a loop current flowing through the trigger coil assembly (30). The superconducting AC current limiter (100) comprises: a cylindrical core (51); a superconducting current limiting coil (3a) wound on the core (51), and inserted into an AC power transmission line, for limiting an overcurrent flowing through the AC power transmission line when a failure happens to occur therein; a superconducting trigger coil assembly (30) coaxially wound inside the superconducting current limiting coil (3a) on the core (51), and magnetically coupled to the current limiting coil (3a), for triggering current limiting operation by the current limiting coil (3a) when most of the overcurrent flows through the trigger coil assembly (30), said superconducting trigger coil assembly (30) being arranged by first, second, third and fourth trigger coils (3B, 3C, 3D, 3E) in such a manner that the first trigger coil (3B) is series-connected to said fourth trigger coil (3E) thereby to constitute a first series trigger coil circuit, the second trigger coil (3C) is series-connected to the third trigger coil (3D) thereby to constitute a second series trigger coil circuit, said first and second series trigger coil circuits are connected in parallel with each other, one end of which is connected to one end of said superconducting current limiting coil (3a) and the other end of which is connected via a quenching switch (3d) to the other end of the current, whereby a synthesized value of voltages (eb, ec, ed, ee) appearing in the first to fourth trigger coils, which are electromagnetically induced by magnetic flux ( phi a) of the current limiting coil (3a) through which the overcurrent flows, is minimized.