State-based Volt/VAR control strategies for active distribution networks

Voltage limit violation represents a crucial power system problem, and many Volt/VAR control (VVC) strategies have been proposed to tackle violations. However, no comprehensive VVC strategy is available for use under all possible system operating conditions. This paper presents a generic solution to the VVC problem of the systems with wind-based renewable distributed generations (DGs) with the primary goal of determining an optimal control strategy based on system status, identified from system voltages. Each state-based strategy has individual state-related objective functions and control devices, including minimization of power losses, operational control costs, and voltage deviation. For both normal-state and intermediate-state operations, the optimization algorithm is implemented, but for emergency states, to be able to take action quickly, a new rule-based control strategy is proposed. Modified IEEE 34 and 123 bus test feeders are employed to validate the algorithm's accuracy under consideration of stochastic nature of wind-based DGs.