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317~463~578(mm) 60Kg 520><250~550(mm) 60Kg 300x1 30~470(mm) I 20Kg -Abstract .. There are many kinds of electronic switching systems in Korea Telecom (KT), because of importing from various countries such as USA, Sweden, Belgium, etc. as well as domestic products. The rectifier system was also imported along with electronic switching systems. It is hard for operators to understand and to maintain them well without troubles. As demands of telecommunications services axe increased, more power systems are required to supply power to telecommunications equipments. Therefore, KT has been developing the new rectifier system to decrease the cost of the rectifier system and the floor space requirements of the conventional rectifier systems now in use. The new rectifier system is composed of a distribution part, a control unit and rectifier modules in one rack. There are three kinds of modules lOOA, 50A, 25A. The maximum output currents of new rectifier modules are lOOOA(lO~OA), 6OOA(50A), 4OOA(25A) in one racks. ' The 25A, 50A rectifiers are used in remote site and lOOA is operated in local. It can reduce annual cost by about 30% for power facility, and electricity. Additionally, the floor space required for new rectifier is reduced by about 50%.This paper describes the configuration and operation of the new rectifier, and reviews evaluation results of the annual cost and floor space of this system compared with the old rectifier.25A S TYPE 490>(250~470(mm)

As the utilization of DC systems increases worldwide, the importance of DC cutoff technology is increasing. We proposed a hybrid DC cutoff technology combining an SFCL (superconducting fault-current-limiter) and a mechanical DC circuit breaker. This model can perform a fault-current-limiting operation through the quenching of the SFCL and a breaking operation through an artificial cutoff zero point of a mechanical DC circuit breaker. In particular, the SFCL is responsible for the growth of the initial fault current according to the DC characteristics. As the DC system’s supply and demand increase, the DC system’s capacity also increases. Therefore, the fault-current-limiting capability of the SFCL should be increased according to the increasing DC system breaking capacity. The fault-current-limiting capability can be increased by increasing the superconducting wires used in the SFCL. Current commercially available SFCLs use bifilar-helical-type and bifilar-spiral-type winding methods. These have the disadvantage of increased volume with increased capacity. To compensate for these disadvantages, we proposed a bifilar-meander-type winding method. In this paper, a new bifilar-meander-type winding method was introduced. In addition, the structural and electromagnetic parts of the existing winding method and the bifilar-meander-type winding method were compared and analyzed for differences. The program used for this analysis is the electromagnetic analysis Maxwell program. As a result, it was confirmed that the bifilar-meander-type winding method is superior to the conventional bifilar-helical and bifilar-spiral types.

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