The nuclear power plants became the Best solution for satisfying the increased and Continuous demand for electric energy due to its very low running cost, its high capacity and supposed to be environmentally clean source of base load electrical generation. For these reasons Egypt decides to begin its nuclear program . Egyptian government signed a contract with Russian Rosatom company specialized in nuclear energy sector to establish EL-Dabaa nuclear power plant in Egypt which is located in Al-Dabaa City, The proposed El-Dabaa nuclear power plant would be consisted of four Reactor of Type VVER 1200 belongs to Generation III to provide the Egyptian unified Electric grid with total power 4800MW. This nuclear power plant will operate as four stages, the first stage is to operate the first nuclear reactor to produce 1200-MW to the Egyptian grid in 2019. the second stage will produce 2400 MW will be in 2023. Then, the third stage will finish the construction of the third reactor and able to be in operation case to supply the total power of the plant to reach 3600-MW in 2026. Finally, the fourth stage will produce the proposed total power to reach 4800-MW in 2028. This Paper discusses the impact of interconnecting between the electric power system of Egypt and EL-Dabaa nuclear power plant are studied and analyzed through simulation of both nuclear power plant and Egyptian electric transmission grid. study for Egyptian unified power system, details for modeling of several elements, where the objective of this study is determining the optimal way for connecting between the proposed El-Dabaa NPP and the Egyptian power system .