Parametric Sensitivity Analysis of STATCOM Supplementary Modulation Controller Incorporated in SMIB System

The low-frequency oscillations (LFOs) in power system occur due to inadequate damping torque of the system and LFOs can be damped using a Static Synchronous Compensator (STATCOM) incorporated with Supplementary Modulation Controller (SMC). However, variation in the parameters of SMC can cause oscillatory modes to collide both in eigenvector and eigenvalues. The major focus of this paper is to discuss a parametric variation of STATCOM SMC and its effect on the stability of the system. The investigation also identifies the limitations on damping of the system for parametric variations of the controller without and with energy sources (ES) at the DC bus of STATCOM. The sensitivity of eigenmodes for system parametric changes is analyzed extensively for the various operating conditions of STATCOM to obtain the safe operating range of controller parameters. The illustrative case studies on SMIB system equipped with STATCOM with and without an energy source shows that identification of a safe range of STATCOM SMC parameters and operating points is highly essential to ensure good damping of the swing mode of generators.