Magnetizing Characteristics of a Flux-Coupling Type Superconducting Fault Current Limiter Connected in Parallel between Two Coils Using an E–I Iron Core

Abstract

In power systems, there are short-circuit faults due to various causes. One way to reduce this fault current is the superconducting fault current limiter (SFCL). Since the current limiter model using a winding includes an iron core, the magnetizing current generated in the iron core when the fault current is limited should not be as large as possible. That is, when saturation of the iron core occurs, sufficient magnetic flux is not generated and the fault current limiting characteristics are degraded. Therefore, in this paper, a flux-coupling type SFCL using an E–I iron core was fabricated to effectively reduce the saturation of the iron core and limit the fault current to twice. The two major windings N 1 and N 2 were connected in parallel, and the peak current limiting characteristics and voltage waveforms were compared based on the winding directions of the two coils. The two main coils were also connected in parallel to analyze the flux linkage and instantaneous power characteristics. The magnetization power area and operating range of the flux linkage based on the magnetic flux energy accumulated in the E–I iron core were compared and analyzed in relation to the increase or decrease of the magnetizing current. © 2019, The Korean Institute of Electrical Engineers.