学科：电力系统及其自动化,出版时间：2019,导师：穆钢指导,学位授予单位：华北电力大学,论文作者：蔡婷婷著,副题名：,学科专业：,关键词：,馆藏号：,
中文
高渗透率风电联网降低了系统的惯性响应和功率支撑能力，影响电力系统的频率质量，制约了联网风电渗透率的提高，风电调频是解决高渗透率风电联网系统调节能力不足的有效手段，研究风电机组的调频控制策略、风电机组参与调频的运行约束及其对调频效果的影响，以及风电调频对高渗透率风电联网系统频率质量的影响，具有理论意义和工程实用价值。 建立了目前主流风电机组——双馈感应风力发电机(DFIG)的数学模型。研究了双馈风电机组的一次调频方法，通过引入功率预留系数和风电机组调差系数的定义，并改进了传统的转速控制、桨距角控制，基于优先电磁调节，尽量避免机械调节的考虑，提出了适应多种风况的转速与桨距角协调控制策略，使风电机组满足电力系统一次调频的功率支撑和惯性响应要求。 针对风电机组的调频能力，指出了风电机组的最大调节功率受额定转速和时间尺度约束。计算了满足电力系统一次调频时间尺度要求的变桨幅度约束，基于风能利用系数与桨距角之间的强非线性关系，提出了分段线性拟合的求解方法，且根据风电机组的基本运行方程，推导了双馈风电机组的最大调节功率表达式。指出了风电机组的双向可调频功率受最大调节功率和功率预留系数约束的关系，并计算了计及全风况的风电机组调频功率约束，整定了功率预留系数的取值。 受调频功率约束的影响，风电机组具有与传统同步发电机不同的功率-频率特性。根据风电机组的调频功率约束和整定调差系数所分配的功率的关系，给出了在全风况下，风电机组的可实现的调差系数域，指出了发生调差系数域外的风速-频率组合事件时，实际调差系数增大。 建立了计及风电联网系统的频率响应模型，以其系统函数说明了高渗透率风电联网对系统频率的影响以及风电参与调频的需求。在风电联网系统调频功率的数学模型基础上，计算了计及频率约束的不同渗透率和不同风速下的风电场调频功率，以及风电联网系统所能接纳的渗透率极值。 在PSCAD仿真平台上搭建了风电联网系统仿真模型，以单个频率扰动，仿真验证了协调控制策略、变桨限幅的正确性及有效性，分析了在不同风速下，风电机组参与调频的功率约束及其影响，以及不同风电渗透率下，风电机组的调频效果和调频贡献。 针对风电参与长周期持续调频问题，以某风电场24小时典型实测数据，在实际频率变化过程中仿真计算了风电场调频功率达到整定调差系数所分配的功率水平的程度，实证分析了长周期持续调频过程中风电场的功率约束和功率预留系数对系统频率质量、风电场调频功率、风功率利用率，以及不同渗透率下系统频率质量的影响。 研究结果表明评估风电机组参与持续调频的效果时必须考虑双向功率约束的影响。 关键词：双馈感应风力发电机(DFIG)；调频；协调控制；功率约束；功率预留系数；调差系数域；风电渗透率
英文
High permeability wind power integrating will reduce the inertial response and power support capability of the system. It affects the frequency quality of the power system, and restricts the improvement of the wind power permeability in the system. Wind power participating in frequency regulation is an effective means to solve the inadequate regulation capability of high permeability integrating system. It is of great theoretical significance and practical value to study the frequency regulation strategies of the wind turbine, the operational constraints of wind turbines participating in frequency regulation and the influence on frequency regulation effects, and the influence of wind power participating in frequency regulation on the frequency quality in the high permeability integrating system. The mathematical model of the current mainstream wind turbine-doubly fed induction generator (DFIG) is established. The primary frequency regulation method of DFIG is studied. According to the definition of power reservation coefficient and adjustment coefficient of the wind turbine, and the improvement of the traditional rotor speed control and pitch angle control, based on the priority electromagnetic regulation and avoiding mechanical regulation as far as possible, the coordinated control strategy of rotor speed and pitch angle is proposed, then the wind turbine meets the power support and inertia response requirements of primary frequency regulation in power system. For the frequency regulation capability of the wind turbine, it is pointed out that the maximum regulation power of the wind turbine is constrained by the rated rotor speed and time scale. The pitch amplitude constraints satisfying the time scale requirement of primary frequency regulation is calculated. Based on the strong nonlinear relationship between wind energy utilization coefficient and pitch angle, the piecewise linear fitting method is proposed. And then according to the basic operation equation of the wind turbine, the maximum regulation power expression of the wind turbine is given. The relationship of which available bidirectional frequency regulation power is constrained by the maximum regulation power and the power reservation coefficient is given. The frequency regulation power constraint of the wind turbine with all wind conditions is calculated, and the value of the power reservation coefficient is set. Under the influence of the frequency regulation power constraints, the wind turbine has the different power-frequency characteristics from the traditional synchronous generator. According to the relationship between the frequency regulation power constraints of the wind turbine and the power allocated by the setting adjustment coefficient, the achievable adjustment coefficient area of the wind turbine under the different wind speeds is given. It indicates that the actual adjustment coefficient will increase when the wind speed-frequency difference combination event outside of the adjustment coefficient area occurs. The frequency response model of wind power integrating system is established, its system function illustrates the influence of high permeability wind power integration on frequency quality and the demand of wind power participating in frequency regulation. Based on the mathematical model of frequency regulation power in the wind power integrating system, the frequency regulation power of wind farms with different permeability and wind speeds is calculated, and the maximum permeability acceptable to wind power integrating system considering frequency constraints is calculated. The simulation model of wind power integrating system is built on the PSCAD platform. With a single frequency disturbance, the correctness and effectiveness of the coordinated control strategy and the pitch limit are verified by simulation. The regulation power constraints and effect of the wind turbine participating in frequency regulation under different wind speeds are analyzed, and the frequency regulation effects and contributions of the wind turbine under different wind power permeability are also analyzed. For the wind power participating in long-term continuous frequency regulation, based on the 24-hour typical measured data of a wind farm. The level of wind turbines frequency regulation power meets the power allocated by the setting adjustment coefficient is simulated and calculated during the course of the actual frequency variation. The influence of wind farm power constraints and power reservation coefficient on frequency quality, frequency regulation power of the wind farm, wind power utilization and frequency quality under different permeability in the long-term continuous frequency regulation process is empirically analyzed. The results show that the influence of bidirectional power constraints must be taken into account when evaluating the effectiveness of wind turbines in continuous frequency regulation. Key Words: Double fed induction generator(DFIG), Frequency regulation, Coordinated control, Power constraints, Power reservation coefficient, Adjustment coefficient area, Wind power permeability
