Optimization of a Wind-Integrated Microgrid System with Equipment Sizing and Dispatch Strategy under Resource Uncertainty

The global quest for energy sustainability has motivated the development of transforming various natural resources into energy efficiently. Combining these renewable energy sources with existing power systems requires systematic assessments and planning. The present work proposes a design procedure for obtaining the optimal sizes of wind turbines and storage devices considering power dispatch with wind and load forecasting. At first, the wind and load models are constructed by wavelet packet analysis and moving average technique. These models are applied to the design procedure to determine the optimal sizes and optimal dispatch strategy. Then, a real-time operating simulation is used to validate the feasibility of the optimal results in the real world. Results show that the models used in the optimization framework should consider the uncertainties to maintain high system feasibility. To quantify the influence of wind and load uncertainties in the optimal sizing and dispatch problem more practically, a novel probability-based power dispatch strategy is proposed. The new strategy estimates a probable dispatch range for a long-term power dispatch and quantifies the variation of the state of charge of energy storages under wind and load uncertainties. The probable dispatch range provides more real-time flexibility for the long-term power dispatch, and the variation provides more information for determination of storage capacity. After determining a suitable storage capacity, a validation simulation is also used to observe the behavior of the power system. Results show that the probability-based power dispatch strategy could estimate the probable range and variation effectively, and that the capacity of energy storage is well determined. This work integrates equipment sizing and power dispatch problem into the design procedure. The procedure provides a gradual planning of a power system, leads the existing power system toward microgrid system, and eventually reaches energy sustainability.