Hierarchical two-level voltage controller for Southern California Edison

The paper proposes a two-level voltage controller for a large power system. The aim of the controller is to maintain the optimal voltage profile in the transmission network by coordinating the VAR control devices in the system. At the local level, the substation controllers maintain their respective substation bus voltages by using mostly local PMU measurements. The central coordinator provides the voltage setpoints to the substations and also coordinates by enabling or disabling the local controllers as needed. The controller is being designed towards prototype implementation in Southern California Edison, starting with local controllers at specific substations in the first stage.