A Generalized Pss Architecture For BalancingTransient And Small Signal Response

Abstract

Power system stabilizers are added to the excitation systems to enhance the damping during low frequency oscillations. Due
to high gain of AVR, terminal voltage of the system stays within control and it improves steady state stability limit, though it
amplifies the negative damping into the system. Power system stabilizers paired with high initial response automatic voltage
regulators have served as an effective means of meeting system stability requirements. They are designed to nullify the
adverse effect of the high gain, fast responding (low time constant) AVR thereby improving small-signal and transient
stability. Driven primarily by increase in power electronically- coupled generation and load, the dynamics of large- scale
power systems are rapidly changing. Electric grids are losing inertia and traditional sources of voltage support and oscillation
damping. The system load is becoming stiffer with respect to changes in voltage. Here we propose a PSS architecture that
can be viewed as a generalization of the standard Δω-type stabilizer. The ability of the stabilizer to improve the damping of
electromechanical modes is decoupled from its role in shaping the system response to transient disturbances. The control
strategy utilizes a real- time estimate of the center-of-inertia speed derived from wide-area measurements. This approach
creates a flexible set of trade-offs between transient and small-signal stability, making synchronous generators better able
to adapt to changes in system dynamics. The phenomena of interest are examined using a two-area test case and simulations
are done on MATLAB platform. The simultaneous focusing on both transient and smallsignalstability showsthe effectiveness
of the proposed control strategy.