Practical Coordination Between Day-Ahead and Real-Time Optimization for Economic and Stable Operation of Distribution Systems

The uncertainty has been one of the main obstacles in the operation of distribution systems with renewable energy resources whose power generation is, by nature, highly intermittent, often resulting in the unbalanced conditions of distributed networks. This unbalance degrades voltage profiles and, thus, aggravates power loss consumed in distributed networks. In this sense, the pragmatic coordination scheme between day-ahead and real-time optimization to achieve economic and stable operation is presented in this paper. At the day-ahead optimization stage, the objective aims to minimize operation costs by controlling the energy storage system such as battery systems. This stage is based primarily on historical data about the daily profiles of power demands or renewable distributed generations, so uncertain elements are always inevitable in operational procedures. The real-time monitoring system plays a pivotal role in computing present operating conditions on a real-time basis sufficient to address these uncertainties of renewable energy resources. The operating conditions are, then, utilized to formulate the objective function and relevant constraints to calibrate control orders once decided at the day-ahead optimization stage. This paper explains the proposed coordination scheme with real-time monitoring capability and, then, presents the test results of numerical experiments with a 15-bus test distribution system.