Chance Constraints Optimal Planning Strategy of Energy Storage Systems and Tie-Lines under Wind Power Uncertainties to Improve the Reliability

The energy storage devices and renewable energy integration have great impacts on modern power system. The optimal site selection and network expansion under several uncertainties, however, are the challenging tasks in modern interconnected power system. This paper proposes a robust optimal planning strategy to find the location and the size of the energy storage system (ESS) among the power network buses and transmission lines expansion to accommodate the wind power energy integration to serve the future demand growth under uncertainties. The proposed methodology provides the optimal location concerning the required size of ESS at each bus, along with the optimal selections to reinforce existing lines or recommending new ones in a single solving stage. The co-optimization problem is formulated as a mixed-integer linear programming problem, in which the power balance constraint is developed as an optimal power flow. The stochastic optimization problem is solved robustly using the chance-constrained method. Furthermore, the load shedding and wind curtailment are taken into account in the cost function. The methodology is tested in the IEEE RTS-96 system. The simulation results demonstrate the effectiveness of the proposed strategy to find optimal size and location of ESS. The optimal candidates and transfer capacity for the tie-lines expansion planning are also determined. The results are found using different confidence levels to assess the optimality when the confidence level changes. The primary generation adequacy indices are evaluated to highlight the effectiveness of the proposed methodology. The optimally sized batteries allocated in the optimally selected locations around the system enhance the system’s performance economically and reliably.