Short-Term Reactive Power Planning to Minimize Cost of Energy Losses Considering PV Systems

This paper presents a new planning framework for minimizing the cost of energy losses by utilizing utility/customer-owned photovoltaic (PV) inverters. First, a new reactive power planning model is proposed to minimize the cost of energy losses by determining the optimal investment in PV inverters considering overrating and/or active power limitation. It provides a tool for utility planners to evaluate the options of utilizing PV inverters, where the inverters are utilized to provide a fixed margin of reactive power, as alternative solutions to the conventional capacitor banks. Second, based on the proposed model, a new planning approach is introduced to cope with the ever increasing renewable energy integration by considering the changing-scenarios of PV installations in terms of numbers, locations, and sizes. The planning approach provides utility-planners with 'flexible' reactive power support options that can change 'adaptively' according to any new connection of utility/customer PV systems in the network. The proposed planning model is formulated using an optimal power flow-based technique, and tested on 16- and 81-bus distribution systems. The performance is evaluated considering various scenarios and by performing sensitivity analyses. The results show that considerable reductions in energy losses' costs can be achieved using the proposed planning approach.