Kabushiki Kaisha Toshiba

The Tokyo Electric Power Company, Incorporated

Takamitsu Tada

Daisuke Ito

Tsukushi Hara

Kazuyuki Tsurunaga

Takeshi Ohkuma

Takahiko Yamamoto

A current limiter having a plurality of current limiting units provided for electric paths constituting a plurality of phases. Each current limiting unit is constituted by a superconducting coil functioning as a first current limiting element formed in a non-inductive winding manner by connecting two superconducting coils in series, which superconducting coils are wound in opposite directions and equal in size and number of turns, and a superconducting coil functioning as a second current limiting element connected in parallel to the first current limiting element and having a predetermined impedance value. These current limiting units are contained within a cryostat and separated by a magnetic shield member for electromagnetically isolating the respective phases.

Superconducting fault current limiter

A superconducting current limiting device for limiting overcurrent flowing in a load. The device includes a current limiter with a first superconducting coil, a second superconducting coil arranged coaxially with the first superconducting coil so as to have a negative magnetic coupling condition, and a third superconducting coil arranged coaxially with the first and second superconducting coils so as to have a negative magnetic coupling condition with the second superconducting coil and so as to have a positive magnetic coupling condition with the first superconducting coil. The first and second superconducting coils are electrically connected in series. The device includes a high speed switch connected electrically in series with the third superconducting coil to form a series circuit. The series circuit is electrically connected in parallel with the second superconducting coil. The device further includes a current monitoring circuit for monitoring current flowing in the load and for generating a signal so as to close the high speed switch when the current flowing in the load exceeds a prescribed value.

Superconducting current limiting device

Growing community of inventors

Chiba, Japan

Takamitsu Tada