The superconducting magnetic energy storage(SMES) unit is capable of controlling both the active and reactive power simultaneously and quickly. In this paper, a control configuration for the active and reactive power simultaneous control of SMES which placed at the generator terminals is presented, and H∞ controller based on Normalized coprime factorization(NCF) approach is applied. Moreover, it is show through simulations, that the controlling sequence of SMES effectively damps out the generator’s terminal bus voltage fluctuations and transmission line power oscillations.