Electric Arc Furnace (EAF) introduces several problems in the power system such as harmonics, voltage flicker, unbalance and voltage fluctuation. Research community has found the solution for these problems by using SVC and STATCOM, but these solutions do not solve all frequency variation issues, which EAF causes in the weak power system. Weak power systems with low inertia and frequency regulation capacity present frequency problems due to active power demand of EAF. According to research presented in this paper, the frequency regulation can be realized by using a special and low energy capacity battery energy storage system (BESS) synchronized with the EAF. It is possible to reduce the frequency problems of the EAF cost-efficiently and therefore, EAF can be installed also to the weak power system.