On selection of supplementary input signals for STATCOM to damp inter-area oscillations in power systems

This paper proposes a method to select the supplementary input signal for systems equipped with static synchronous compensators (STATCOM) to damp inter-area mode(s). Input-output observability-controllability analysis, minimum singular value, right half plane zeros and relative gain array are used to assess the most appropriate supplementary input signal. The open-loop frequency of the system is shown to examine the sensitivity of the selected supplementary input signal to inter-area mode. The method is applied to select the input signal for a small power system equipped with a single STATCOM and for a large power system equipped with two STATCOMs.