Optimal Control Strategy And Sizing For BESS Regulating Fluctuations Of Grid-connected Wind Power

With the rapid growth of economy, global demand for electricity is in continuousgrowth as well. However, fossil fuel exhaustion and environmental pllution is seriousincreasingly, thus promoting the booming of renewable energy sources generation,such aswind power. Wind is a promising clean and inexhaustible energy source, while itsuncontrollable, stochastic and variable characteristics make wind power different fromconventional power plant. High wind power penetration will affect the operational securityand reliability of power system greatly. Rate of wind power fluctuations influnces thefrequency stability of power system. So with the installed scale of wind power andconnection to grid growing, taking effective measures to stabilize output of wind farmsmay mitigate its negative influnce to power system,ensure the operational security andreliability of power system. On the other hand, it may provide support of high penetrationwind power to connect to grid, promote development of wind power.With the contradiction of modern late-model power system increasingly exposing,people pay more attention to application of energy storage technology.Possesing manyadvantages to others, Battery Energy Storage System(BESS) can charge and dischargemass electric energy, to compensate unbalance power of system; can follow power changerapidly with a short in response time; with flexible installation, being independent oflacation constraints. At large-scale wind farms, to allocate appropriate capacity BESScooperate with wind power utilizing reasonable control strategy can improve powerquality of wind-BESS output, relieve frequency adjustment pressure wind power bring topower system.While, the cost of BESS increase when its scale enlarge, in order to receivethe most benefit, it is necessary for wind farms to optimize BESS capacity. Then it mayrealize the double requirements of economics and technical.In this paper, the relevant problem of output characteristic of wind farms andgrid-connection requirements of system will be analyzed. Firstly, Detailed analysisinfluence of wind power fluctuation rate on the the system frequency, propose aforward-looking control strategy for BESS; Secondly, establish wind farm profit model including fluctuation out-of-limit punitive cost,then optimize capacity of BESS for thegoal of revenue maximization.The models and methods proposed by auther have been tested through the actualexamples strictly. The testing results show that the methods and models proposed have astrong theoretical forward-looking,can better control rate of wind power fluctuations,contribute to the operational security and reliability of power system; the objectivefunction proposed based on maximize revenue of wind farms can help choose suitablescale of energy storage for given wind-connected grid, increase economic benefit of winddevelopers, and adapt to the development planning of late-model power system.