【作者】 刘雪芳；

【导师】 王洪涛；

【作者基本信息】 山东大学 ， 电力系统及其自动化， 2013， 硕士

【摘要】 风力发电作为一种环境友好型发电形式,越来越受到重视,风能资源得到大规模地开发和利用。然而,大规模风电并网也给电网带来了诸多挑战,无功电压协调控制是其中之一。风功率的波动性是引起电压波动的根本原因。风能资源的随机性和波动性,风电场中不同时间尺度无功电压调节装置的响应特性,增大了无功电压协调控制的难度。本论文以此为背景,展开了大规模风电场无功电压协调控制的研究。首先,研究了常用的三种风机类型,包括定速异步风机,变速双馈风机和永磁直驱同步风机。建立了定速异步风机的等值电路图,推导了其无功功率与机端电压、有功功率等的关系；研究了双馈定速风机的矢量控制策略,推导了其无功功率极限。此外,研究了风电场中常用的几种无功电压调节装置的性能：包括并联电容器组、有载调压变压器、静止无功补偿器和静止同步补偿器。其次,研究了风电并网对电网电压的影响。推导了风电场影响无功电压特性的原理；分别研究了定速风机并网、双馈风机恒功率因数并网和双馈风机定电压并网对电网电压的影响；此外,还研究了风电场接入系统不同节点对电压的影响。最后,以上述研究为基础,构建了大规模风电场参与系统无功电压控制的控制模式,包括系统层控制、风电场级控制和设备层控制。针对风电场级控制,提出了风电场群两层多阶段无功电压协调控制模型,该模型计及了风功率的不确定性以及多时间尺度调压装置的响应特性。建立的模型是多目标问题,采用NSGA-Ⅱ(fast and elitist non-dominated sorting genetic algorithm)算法进行求解,对求解结果应用层次分析法(Analytic Hierarchy Process)从Pareto最优解中选取决策方案。采用多风电场接入电网典型拓扑图验证了所提出了模型可以有效的抑制风速波动带来的电压波动,同时可以减少离散设备的调节次数达到经济性的目的。更多还原

【Abstract】 Wind power is taken seriously as a kind of environment friendly plant style. And wind resources are developed and utilized on a large scale. However, many challenges are brought to the grid because of the integration of large-scale wind power. Reactive power and voltage control is one of the challenges. The fluctuation of the wind power is the fundamental cause, which brings about the voltage fluctuation. Randomness and fluctuation of the wind, response feature of different time scale regulation devices in the wind farms combined increase the difficulty of the reactive power and voltage control. The thesis makes a study of reactive power and voltage control of large scale wind farms in the above background.Firstly, three common kinds of wind turbines are studied, including fixed speed induction generator (FSIG), doubly fed induction generator (DFIG) and permanent magnet synchronous generator (PMSG). Equivalent circuit of FSIG is established, according to which the relation of reactive power, terminal voltage and active power is deduced; vector control of DFIG is studied and reactive power limit is deduced. Besides, the features of several reactive power and voltage regulation devices are studied:including shunting capacitors, on load tap changer (OLTC), SVC and STATCOM.Secondly, influence to the grid voltage of wind power integration is studied. First of all, the principle of the influence of wind farms to the feature of reactive power and voltage is given; next, the influence to the grid voltage of three cases is studied, including FSIG as the wind turbine type, DFIG as the wind turbine type of constant terminal voltage and constant power factor; and then, the influence to the grid voltage when wind power integrates to the grid from different buses.Finally, on the above basis, the reactive power and voltage control mode of large scale wind farms integrating into the grid is constructed, including system level control, wind farm level control and devices level control. For the wind farm level control, a control strategy of two-tier and multi-stage of wind farm cluster is proposed. The model considers the uncertainty of the wind power and the response features of different time scale devices. NSGA-Ⅱ (non-dominated sorting genetic algorithm Ⅱ) is selected to solve the model, because the model is a multi-objective problem. After the solution, analytic hierarchy process is used to select a best solution for the operator. At last, a typical topology of multiple wind farms integrating to the grid is used to testify the proposed model, which can control the voltage fluctuation caused by the wind speed fluctuation and decrease the switching times of discrete devices, obtaining the economic objective.更多还原