Abstract: In order to integrate the reactive current compensation and the selective harmonic current compensation ability for STATCOM（Static Synchronous Compensator）,a reduced order generalized integral（ROGI）-based control strategy is proposed.It extracts the fundamental active current,harmonic current and reactive current in stationary reference frame,and the multi-ROGI（Reduced Order Generalized Integrator） resonant controllers are used to compensate the selected order harmonic current.The grid frequency is estimated by the frequency-locked loop,and the resonant frequency of the ROGI controller is actively adjusted according to the estimated frequency,which can improve the harmonic current compensation controller performance under the grid frequency variation conditions.The control strategy is carried out in the stationary reference frame.Thus,it does not require voltage phase-locked loop and synchronous rotation transform.The experimental prototype was built to verify the proposed control strategy.Experimental results show that the proposed control strategy can effectively compensate the selective harmonics and reactive current,and show the robustness for the grid frequency variation.