Three-winding coreless superconducting fault current limiter

Abstract

Fault current is one of the basic threats to the elements of power systems. Fault current flow can cause thermal and dynamic harmful effects on the operation of power equipment. An ideal fault current limiter is required to have zero impedance at work currents and substantial impedance in short-circuit conditions. These requirements are met by superconducting fault current limiters which use the phenomenon of transition of a superconducting material from the superconducting state to the resistive state as a results of exceeding the critical current Ic of the superconducting material [1]–[3]. An inductive fault current limiter is a triple-winding construction consisting of two superconducting windings and one copper winding, which are magnetically coupled with each other. Both superconducting windings are wound simultaneously on one carcass, which allows to obtain a very large magnetic coupling coefficient between the windings, minimize the dispersion reactance of the limiter, which in turn minimizes the voltage at the limiter in the waiting state. The limiter is lightweight due to its coreless design and cryogenic cooling of the copper winding.