변압기 비율차동계전기의 보호협조 운용방안에 대한 알고리즘 개발

Abstract

Recently, most electrical system failures are difficult to identify with the naked eye due to the trend of cutting-edge and mass capacity of electrical facilities, and the failure section is determined through the operation of the protective relay. In addition, the protection range of the protective relay is wide, and many hours, manpower and costs are involved in the identification of the correct fault site, and electrical safety is a problem. Therefore, in this paper, as a digital ratio differential relay of a power transformer, malfunction cases and occurrence mechanisms of RDR(Ratio Differential Relay), an electrical protection device installed as an automatic shut off device in the event of a transformer internal failure, are analyzed, and the ratio We propose an algorithm for preventing malfunction of differential relay. As a result of analyzing the malfunction characteristics of the ratio differential relay based on the implementation of the proposed algorithm and test device, when the ratio differential relay is operated according to the proposed algorithm, it is possible to prevent malfunction without separate wiring and changing the CT(Current Transformer) installation location. Therefore, it was possible to confirm that the algorithm presented in this paper is useful.