Loadability of power systems and optimal SVC placement

This paper investigates the loadability of power systems. A voltage stability assessment is performed using the worst-case reactive power margin as an index. In addition, the influence of active power load increment on the voltage stability assessment is also examined. Based on these results, a messy genetic-algorithm optimization scheme is proposed for optimal static VAR compensator (SVC) placement aimed at the voltage stability enhancement of power systems under the most critical operation conditions. The SVC planning is formulated as a multi-objective optimization problem in terms of the maximum worst-case reactive power margin, highest load voltages towards the critical operating points, minimum real power losses, and lowest SVC device costs. During the genetic algorithm search for the optimal solution, the most critical disturbance scenario is estimated using each SVC placement and the configuration of the original power system. The candidate solution thereby obtained is further checked against the N - 1 security criterion.