The paper describes the static and dynamic performances of the main transmission system of Oman with the 400kV Gulf Cooperation Council (GCC) electricity interconnection between Oman and Abu Dhabi. A detailed model of the transmission system of Oman is obtained to simulate the steady-state and dynamic system performances using the DIgSILENT software. The model includes simulation of the generating units at power plants with their turbines, speed governors, exciters and voltage regulators. The UAE system is represented by an external source. Simulation results are presented to show the feasibility of successful operation with exchange of up to 400MW between Oman and UAE in either direction in 2014. The results include line and transformer loadings, voltage profiles, fault currents, and dynamic system responses to tripping the 400kV interconnector.