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A 22.9 kV class hybrid fault current limiter (FCL) developed by Korea Electric Power Corporation and LS Industrial Systems in 2006 operates using the line commutation mechanism and begins to limit the fault current after the first half-cycle. The first peak of the fault current is available for protective coordination in the power system. However, it also produces a large electromagnetic force and imposes a huge stress on power facilities such as the main transformer and gas-insulated switchgear. In this study, we improved the operational characteristics of the hybrid FCL in order to reduce the first peak of the fault current. While maintaining the structure of the hybrid FCL system, we developed a superconducting module that detects and limits the fault current during the first half-cycle. To maintain the protective coordination capacity, the hybrid FCL was designed to reduce the first peak value of the fault current by up to approximately 30%. The superconducting module was also designed to produce a minimum AC loss, generating a small, uniform magnetic field distribution during normal operation. Performance tests confirmed that when applied to the hybrid FCL, the superconducting module showed successful current limiting operation without any damage.

High-temperature superconducting tapes have been applied to diverse power devices through previous researches. Nevertheless, there has been no clear theoretical investigation of a mix of superconducting and normal conditions; in particular, there have been poor researches on changes in properties by kinds of superconducting tapes in case of mechanical transformation for application to devices. In this study, therefore, we discovered voltage–current and resistance properties by kinds of superconducting tapes and stabilizing materials through a test and compared and examined effects of mechanical transformation of each tape. To do this, Bi-2223 tapes and two kinds of YBCO tapes with different stabilizing materials were selected and divided in the unit of 100 cm to compare the resistance curve between the straight state and the wound state with mechanical transformations. In addition, current application properties of tapes were examined according to series and parallel connection with tapes wound round the manufactured former.

YBCO coated conductor tapes with high critical current density and index values are expected to be applied to superconducting power device. In particular, it is characterized by possibilities of selecting a stabilizing material surrounding superconducting tapes and of being applied to superconducting fault current limiters (SFCLs) and superconducting cables according to resistivity. In this study we conducted a test by selecting tapes with critical current of 85 A using copper as a stabilizing material in consideration of these properties to see their applicability to superconducting cables. We also conducted a test by selecting superconducting tapes using stainless steel as a stabilizing material to see their applicability to SFCLs. These tapes had the critical current of 60 A, which was somewhat lower than those for superconducting cables. Finally, superconducting tapes selected in this way were used to compare and review each of voltage–current and resistance properties; on the basis of those results of the review, an experiment of connecting those two kinds of tapes was carried out to see if superconducting tapes whose stabilizing material was copper applied as a protected could operate within the range which didn’t exceed the critical temperature.