提高频率稳定性的风储联合系统控制策略研究

发布时间：2018-10-22 07:09

【摘要】：风力发电具有随机性与波动性,风电场并网后对系统频率造成波动,随着风电渗透率在电力系统中的不断增大,风电并网对电力系统频率的影响日益显著。目前风电机组普遍采用最优功率运行模式,不能参与电网调频调度,而采用降载运行留有有功余量势必会损失风电机组发电效率,如何在保证风电经济运行的前提下最大程度发挥其调频能力,成为建立电网友好型风电场的关键问题。针对该问题,本文研究风电机组调频有功裕度、风速阈值和储能容量配置整定方法,利用风电机组和储能系统在功率传输与调频能力上的优势互补,采用风储联合调频控制方法,提高电力系统频率稳定性。首先,根据双馈风力发电机三相静止坐标系与两相旋转坐标系下的数学模型,完成风力发电系统有功、无功功率解耦控制,对双馈风力发电机建模。利用等值法建立风电场动态聚合模型。根据电池储能系统结构、数学模型及工作原理进行建模,为仿真分析奠定基础。其次,提出计及风速波动区间的风储联合调频控制策略。在低风速区,风电机组按最优功率模式运行,由储能系统提供调频备用;在高风速区间采取风储协调控制方法进行调频,风电机组降载运行,留有有功余量,配合电池储能系统出力对电网进行频率支撑。所提出的风储联合系统调频控制策略,在提高电网频率稳定性的基础上兼顾了风电场的经济性运行。再次,分析风储联合系统参与系统调频的理论,根据所提出的风储联合调频控制策略,采用不同风速下风储联合系统采用多种控制方法相结合的调频方法,分析研究风电机组桨距角控制、电池储能系统荷电状态分区控制以及风机转子转速恢复控制,将风机与储能调频技术相结合运用于风储联合系统调频控制。最后,在DIgSILENT/PowerFactory仿真环境下,搭建风储联合系统调频仿真模型,对低风速、高风速及变风速三种工况下,系统频率变化与运行状况进行仿真分析。结果表明,论文所提出的计及风速波动区间的风储联合调频控制策略,可提高电网频率稳定性,加快系统对频率变化的响应速度,同时避免频率的二次跌落。在仿真分析的基础上,运用RT-LAB进行半实物仿真实验,验证风储联合系统参与系统调频的可行性。
[Abstract]:Wind power generation has randomness and volatility. Wind power grid brings fluctuation to the frequency of the power system. With the increasing of wind power permeability in power system, the influence of wind power grid connection on the frequency of power system becomes more and more obvious. At present, the wind turbine generally adopts the optimal power operation mode and cannot participate in the frequency modulation dispatching of the power grid. However, it is bound to lose the generating efficiency of the wind turbine by using the active power allowance left in the download operation. How to maximize the FM capability of wind power under the premise of ensuring the economic operation of wind power has become the key problem in the establishment of grid friendly wind farm. In order to solve this problem, this paper studies the tuning method of FM active power margin, wind speed threshold and energy storage capacity of wind turbine, and makes use of the complementary advantages of wind turbine and energy storage system in power transmission and frequency modulation capability. The frequency stability of power system is improved by using air storage combined with frequency modulation control method. Firstly, according to the mathematical model of three phase static coordinate system and two phase rotating coordinate system, the active and reactive power decoupling control of wind power generation system is completed, and the model of doubly-fed wind turbine is established. The dynamic aggregation model of wind farm is established by equivalent method. According to the structure, mathematical model and working principle of battery energy storage system, this paper establishes the foundation for simulation and analysis. Secondly, a combined FM control strategy with wind speed fluctuation interval is proposed. In the low wind speed area, the wind turbine operates according to the optimal power mode, and the energy storage system provides the frequency modulation reserve. In the high wind speed range, the wind turbine operates at lower load by adopting the coordinated control method of the air storage. Cooperate with the battery energy storage system to carry on the frequency support to the power grid. The proposed FM control strategy of the combined wind-storage system takes into account the economic operation of wind farms on the basis of improving the frequency stability of the power grid. Thirdly, the paper analyzes the theory that the combined air storage system participates in the frequency modulation system. According to the proposed control strategy of the air storage joint frequency modulation system, the combined air storage system under different wind speeds adopts a combination of multiple control methods. This paper analyzes and studies the pitch angle control of wind turbine, the zone control of charging state of battery energy storage system and the speed recovery control of fan rotor. The combination of fan and energy storage frequency modulation technology is applied to the frequency modulation control of combined wind storage system. Finally, in the DIgSILENT/PowerFactory simulation environment, the FM simulation model of the combined air storage system is built to simulate and analyze the system frequency change and operation state under three operating conditions: low wind speed, high wind speed and variable wind speed. The results show that the proposed combined FM control strategy with wind speed fluctuation can improve the frequency stability of the power network, accelerate the response speed of the system to the frequency change, and avoid the secondary frequency drop at the same time. On the basis of simulation and analysis, the feasibility of air storage joint system participating in frequency modulation is verified by using RT-LAB in the hardware-in-the-loop simulation experiment.
【学位授予单位】：沈阳工业大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TM614;TM712

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