Coordination of Preventive and Corrective Control for Voltage Stability of Power System

Power systems operate close to their voltage stability margin owing to the high load demand. To prevent voltage collapse, the system operator must be aware of the system functionality and be prepared to implement preventive and corrective control measures. Hence, an appropriate algorithm to determine the time required by the operator is crucial, making it necessary to adopt appropriate models for effective implementation. Based on the load prediction curve for each bus, a new method is proposed to estimate the remaining time before voltage instability. Furthermore, an algorithm is developed to select the most suitable control action (preventive or corrective) based on the remaining time until the power system voltage instability occurs. In this study, two models based on voltage stability-constrained optimal power flow (VSC-OPF) are proposed, incorporating voltage stability index constraints for both control types. The effectiveness of the proposed algorithm and models is assessed using the IEEE 14- and 57-bus power systems, thereby demonstrating promising results.