The present disclosure relates to an energy management system (EMS) and a method using the same, wherein the EMS comprises, a communication module receiving a channel information of a high voltage direct current (HVDC) system via a network; a circuit realization unit obtaining a connection information among constituent elements symbolizing the constituent elements among each node in electrical symbols by sequentially following pre-set nodes of the HVDC system, and forming the HVDC system by connecting the symbolized constituent elements using electrical lines by using the channel information of HVDC system received by the communication module; a system analyzing unit analyzing an operation mode of the HVDC system through the connection information among the constituent elements of the HVDC system obtained by the circuit realization unit; and a controller managing and controlling the HVDC system by giving an energy management command in response to the operation mode analyzed by the system analyzing unit.