Renewable energy is attracting attention as a future energy source and the energy mix of the power system is changing from the conventional fuel and nuclear energy to the renewable energy. As a result, uncertainty and volatility are increasing in the power system operation. To cope with the volatility and uncertainty, the flexibility and efficiency are required in the power system which are the controllable device can provide. Therefore, various functions are required for controllable device such as High Voltage Direct Current(HVDC), Static Var Compensator(SVC), Static Synchronous Compensator(STATCOM) and Energy Storage System(ESS). Inertia Emulation Control(IEC) has been studied in HVDC to improve stability of the power system. In Jeju island, Voltage Source Converter(VSC) HVDC is under planning and the rated capacity of the DC system corresponds approximately 20% of peak load. Thus, the stability of the island power system can be improved by control of the HVDC. In this paper, the system parameters of the DC system for improving the stability of the Jeju system by IEC are calculated from the energy aspect. The amount of energy change was calculated for the contingency which the frequency fluctuation causes the under frequency relay operation. Based on the amount, the energy compensation amount to maintain the frequency of the DC voltage variation.