Predictive Set Point Modulation to Mitigate Transients in Lightly Damped Balanced and Unbalanced Systems

Abstract

Power system controllers are designed and tuned to achieve the desired dynamic performance under prespecified system conditions. However, changes in the system, e.g., load variation, generation changes, and faults, can cause departure of the system from previously assumed parameters. This in turn can change and reduce damping, which may enable large transients to violate the operational limits of a controlled apparatus. Set point automatic adjustment with correction enabled (SPAACE) is a strategy that modulates the set point of an apparatus to mitigate such transients. This paper 1) proposes a quadratic prediction algorithm for SPAACE to enhance its performance, 2) presents a supplemental strategy to improve set point tracking even when limits are not violated, 3) introduces an approach to implement SPAACE in unbalanced systems, and 4) analyzes the stability of SPAACE. Several case studies are presented to demonstrate the superior ability of this strategy for mitigating transients in different scenarios compared to conventional PI-based control strategies.