Optimal Placement of Energy Storage in a Power System with Wind Generation

This paper presents an approach to improve the performance of a power system with wind generation through the addition of energy storage systems. Optimal power flow is used to evaluate the benefit of energy storage systems placed at the site of varying wind generation and/or location of a fluctuating load. Objectives considered for improvements in performance over time include reduction of a conventional (nonrenewable) generator's output power, smoothing of a conventional generator's output power to lessen ramping, and reduction in transmission losses. A single-phase, transmission-level model of a five-bus power system was selected as the test system for this study and incorporates time-series data collected from a wind farm and load at 30-minute intervals. Results are presented for the three objectives and energy storage systems placed at one, or both, of two possible locations. In all scenarios, the performance of the power system was improved as expected with the selected objective. The improvements can be viewed qualitatively in figures of the conventional generator's power and line powers, and quantitatively in tables of values calculated for the cost functions (also taken as metrics) in all scenarios. The best results were achieved for an energy storage system co-located with the fluctuating load, which was followed closely by the second-best option of an installation of energy storage systems at both the varying wind farm and fluctuating load.