Multi-Period Optimization for Voltage Control System in Transmission Grids

Automatic Voltage Control (AVC) systems maintain the voltage in an acceptable range and minimize the power loss of the grid by coordinately regulating the controllable components. Switchable shunts and tap-able transformers are expected to be operated as few times as possible. This paper proposes a two-level, multi-period optimal reactive power flow approach. In the upper level, the real-time measurements and short-term forecasts are used as the inputs of the multi-period optimization for one hour with 15 minutes intervals, to minimize the operational cost, subjected to a certain constraints. In the lower level, the optimization is focused on the correction of the voltage violations every single minute based on data from the measurements and state estimation. The presented case study shows that the multi-period optimization in the upper level of AVC system can reduce adjustment times of the discrete components for saving the total operational cost.