In this paper, we develop a explosion-proof LED lighting (Ex circuit) circuit of Explosion-proofLED Signal Lamp (Ex LSL) to utilize the core module of the explosion-proof Local Control System (ExLCS) for offshore plant applications. And then analyzed its electrical, optical and thermal characteristics. Ex circuit was applied input voltage from AC/DC(12～254) V. In this experiments, stable light-oncharacteristics were confirmed by eyes for the every input voltages with min. 78,462 and max. 517,975cd/m2 of luminance. also Output current and output luminance was made proportional. Because themeasured maximum surface temperature of Ex circuit was 54.23℃ at AC 48 V, Ex circuit was rated withT6 of temperature class. Finally, Ex circuit was shown stable light on characteristics under the?50℃ and60℃ during 12 hours of test period.

The series connection-type superconducting fault current limiter (SFCL) with two magnetically coupled circuits was suggested and its effectiveness through the analysis on the current limiting and recovery characteristics was described. The fault current limiting characteristics of the proposed SFCL as well as the load voltage sag compensating characteristics according to the winding direction were investigated. To confirm the fault current limiting and the voltage sag suppressing characteristics of the this SFCL, the short-circuit tests for the simulated power system with the series connection-type SFCL were carried out. The series connection-type SFCL designed with the additive polarity winding was shown to perform more effective fault current limiting and load voltage sag compensating operations through the fast quench occurrence right after the fault appears and the fast recovery operation after the fault removes than that with the subtractive polarity winding.