A Generalized PSS Architecture for Balancing Transient and Small-Signal Response

Abstract

For decades, power system stabilizers (PSS) paired with high initial response automatic voltage regulators (AVR) have served as an effective means of meeting sometimes conflicting system stability requirements. Driven primarily by increases 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. In parallel, advancements in wide-area measurement technology have made it possible to implement control strategies that act on information transmitted over long geographical distances in nearly real time. We present a PSS architecture that can be viewed as a generalization of the standard Δω-type stabilizer. 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 response, 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 a reduced-order model of the North American Western Interconnection. To validate the key findings, we employ a state-of-the-art co-simulation platform to combine high-fidelity power system and communication network models.