| As the ecological environment problem has become more and more seriously in recent years, renewable energy usage has been more important. Been one of the renewable energy, wind energy has gained reputation of fast growth and best economic. With the increase of wind farm penetration, the instability of wind energy has affected power system much more than before. A fluctuating power output of wind farms will affect the stability of interconnected grid frequency and voltage.Wind-Storage system can effectively smooth fluctuation of wind power and improve the system reliability, thus improve the quality of power supply. So the system is widely been studied in recent year. In order to smooth the wind fluctuation and improve the reliability of the electrical power system with wind power integration, this paper has done the following work.Firstly, based on the analysis of different wind speed simulation models and wind farm output power models, simulated wind speed by ARMA model, and established wind power system; Analysed technical indexes of common energy storage devices and Chose the lithium ion batteries which are most widely used to establishing corresponding energy storage system model. The model of Wind-Storage system has been set up on the basis of analysing different wind-storage combined methods.Secondly, established the evaluation system for electrical power system reliability and fluctuation. The IEEE-RTS79 test system with actual wind power integration were evaluated. By comparing the reliability evaluation result of sequential simulation and the non-sequential simulation in a instance, explained the difference between two simulation methods. Discussed reliability changes when replacing some conventional units to wind turbines; The wind power fluctuation of 10 min time scales and 1 h time scale were evaluated and compared, too.Then, this paper put forward an energy storage control strategy based on fuzzy algorithm. The control strategy aims at controlling charging and discharging energy storage process based on wind power and load changes. The strategy were realized by the MATLAB program. From the fluctuating and reliability assessment results or the intuitive figure, we can conclude that the power system reliability was improved and the wind power fluctuation was reduced. What’s more, with the increase of energy storage capacity, the improvement effect was leveling off, but there’s a saturation point.Lastly, the State of Charge control strategy was proposed by intervening in battery charging and discharging to manage State of Charge (SOC) of battery. Contrast the optimized SOC probability distribution and the optimized SOC real-time curve with before respectively, the SOC was better controlled and the overwork was reduced a lot. The simulation results validate the effect of this strategy, and longer life of battery were verified. In views of the optimized system reliability indexes and the real-time curve, the optimized system reliability improved slightly and the wind curtailment fell. But the fluctuation was increase.In this paper, the research has made some achievements, but still in deficiency. The limit of line transmission capacity was ignored which may affect the reliability of the system; In the study of wind power fluctuation, the related situation of 1 minute time scales was not further explored; The fuzzy control strategy and the SOC control strategy provides a new way of thinking, and they could be continue to study in depth. |
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