Research On Flexibility Analysis Of Power System And Wind Power Penetration Limit

Intelligence is the ultimate objective of development of power system, and flexibility is used as the necessary means for the development of smart grid. At present, flexibility technology applied a little in system programming and power dispatch is less likely to be applied widely and deeply in power system. It was originally applied in Flexible Alternative Current Transmission Systems (FACTS) denoting the electronics and electric devices applied in power system.The"Flexible"referred to the controllable voltage and current. With the development of modern power system, the flexibility technologies based on power electronics chould not meet the need of flexibility for the modern power system. Flexibility of power system embodies mostly the controllability and and responsiveness of power system when system parameters changing. Especially, the development of intermittent energy sources puts forward a higher damend for the flexibility of power system.Wind power is currently the most mature technology in renewable?energy power generation. With the capacity of wind farm increases, the operation of large-scale wind farms has an effect on voltage and frequency. In orde to maximize wind power under the condition of nomal operation of power system, determining the wind power penetration limit and influence factors become a key problem in the work of planning wind farm.In background of the development of smart grid, this paper carries out research on flexibility concept and flexibility analysis technology which are suitable for smart grid and applied in development and utilization of new energy. From the perspective of power system, the lackness of application of flexibility technology in power system is analyzed, and the flexibility concept suitable for smart grid is proposed. Through the flexible representation of uncertain parameters, a flexible evaluation model is proposed to determine the power system is safe or not when system parameters changing. Then, a variable flexible evaluation model is proposed with flexible index defined to assess the margin of system security. Finally, a flexible optimization model and an optimize flexibility model are proposed based on flexible evaluation model with economic functions introduced, which is an integrated optimization of economy, security and reliability not only for the optimization of state and control variables, but also for the parameters. Finally, the proposed model is introduced into the study of wind power penetration limit, and a method based on flexibility assessment of power system is proposed with the randomness of wind power is flexible expressed by introducing flexible parameter. Further, an optimize flexibility model is proposed with the randomness of wind power is quantified as flexible cost into the operation value of wind power, which makes the economic and security of planning combined organically and realizes compromise decision-making between grid-connected wind capacity and operation value of wind power and is adapted to the actual needs of department for network planning.The calculating results on IEEE-30 system demonstrate the flexible expression of wind power reflect the randomness of wind power output absolutely, and the flexibility assessment analysis, which is a deterministic analysis method for uncertain information, achieves the extension towards uncertainty areas.