This paper describes the consideration of 154kV protective relaying systems for applying HTS(High Temperature Superconducting) power devices to Korean power system. We investigates firstly 154kV relay systems of Korean power system and then do a basic study on the relay systems in the power system with superconducting devices. For the more detailed result, the study using EMTDC relay system modeling will be done from the viewpoint of superconducting devices application in the future.