The proposed multi-area voltage control scheme is essentially “problem-oriented”, which closely follows system operator’s philosophy. It divides the network into separate control areas dynamically according to current system conditions. First, the SCADA voltage measurements are checked to decide whether there is any voltage outside a specified band around some “optimal” voltage profile. If any voltage violation exists, the violating buses are located and grouped into separate problematic control areas. In the following simulations, the local control areas are constructed such that the buses within 6 tiers of the control bus are included. The step-size for LTC tap changing is set to one tap at a time and the step-size for generator voltage adjusting is set to 0.01 p.u. The rules for calculating the costs of control actions are same as before, i.e. the cost for switching out a capacitor or reactor bank is zero, the cost for switching in a capacitor or reactor bank is 100.0, the cost for LTC tap changing is 200.0, and cost for generator voltage adjusting is set to 300.0. For any type of device, the cost of next action will increase by 10.0, and decrease by 1.0 at each time step. The control objective is to maintain all bus voltages within 2% band around the pre-defined voltage profile, and the maximum allowed voltage deviation is 5% away from the optimal value. The voltage penalty coefficient λ is set to 1.0 and the maximum voltage penalty P0 is set to 7.5 for test purpose. The first simulation scenario is that both system experience line outages and/or load variations, thus voltage problems occurs simultaneously in both areas, and then the lines go back to service with load back 75 to normal

problem-oriented, measurements, simulations, voltage penalty coefficient