Energy management system using policy based hierarchical simulation framework

The number of distributed generation (DG) and storage units has increased and the integration and management of DGs have gained vital importance since they are connected to the utility grid. A two-level hierarchical simulation is proposed for Energy Management System (EMS) that includes photovoltaic (PV) system, battery, and residential load that are connected to the utility grid. The high-level model implements an energy management policy containing energy distribution and grid purchase rules for optimum operational decision making. Using meta-heuristic optimization tools, the policy can be optimized by adjusting underlying parameters (e.g., level of minimum storage, grid price threshold) to minimize the total cost. The high-level model is based on system dynamics (SD), which simulates energy flows between different components based on the policy and sends control signals to the lower level. The low-level simulation is based on circuit-level continuous time modeling and concerns converters' control strategy to maintain the required power quality. Simulation models at both levels are federated via SOAP-based Web Services. Integrated simulations have been used to conduct experiments, whose results reveal that the proposed technique successfully controls the converters and provides uninterrupted power to the load with a policy that leads to minimum total cost.