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Low frequency oscillations with growing amplitude can be a threat to secure operation of power system. Such oscillatory behaviour can be dealt with proper design of supplementary controller with the best input signal. This paper presents a design of supplementary controller for static Var compensator (SVC) using H∞ loop-shaping technique to damp low frequency, in particular inter-area oscillations. This design technique uses a normalised coprime factor approach for robust stabilization of the system. Proper feedback signal from the available measurements across the system plays vital role on the damping performance of the designed controller. The residue analysis is used to select the best feedback signal. Effect of local as well as global signal on the performance of the designed controller is compared. Eigenvalue analysis and time-domain simulations are used to demonstrate the effect of decentralized and centralized SVC controller on dynamic behaviour of an IEEE benchmark two-area power system.