并网风电场无功控制与电压稳定研究

发布时间：2018-03-24 11:46

本文选题：风电场　切入点：双馈风电机组　出处：《上海电力学院》2014年硕士论文

【摘要】：面对传统化石能源的日益枯竭和能源开发利用造成的环境污染，能源和环境成为社会发展急需解决的问题，风能以储量大、清洁、可再生等优点得到广泛使用，利用风能的发电技术得到快速发展，大规模风电场不断出现。风电接入电网对电网的安全稳定运行带来重大挑战，其中风电接入电网的无功控制和电压稳定问题是最受关注和急需解决的问题。我国新建的风电场多采用变速恒频双馈感应风电机组，该机组已成为国内主流风电机型，本文针对双馈风电场接入系统引起的电压稳定问题对风电场的无功控制和电压稳定展开研究。首先，本文分析了风速模型和风力机的气动特性，并介绍了双馈感应风力机的数学模型，讨论了双馈风电机组的功率传输特性，根据数学模型和功率传输特性计算出双馈风机的无功极限，分析了双馈风机的运行控制区域和运行控制方式。其次，本文分析了风电场中风机的尾流效应影响，根据尾流效应对风机划群，考虑等值前后的功率损耗和电压降落相同提出了一种平坦地区风电场的动态等值计算方法，探讨了并网风电场的电压稳定研究方法。对某风电场进行仿真研究，，通过风电场静态电压稳定分析得到风电场薄弱母线，并对双馈风电机组的恒电压运行方式和恒功率运行方式在暂态中的影响进行分析讨论。由于风电场有功出力随风速变化具有随机性和波动性，风电场发出或吸收无功将随有功出力波动变化，风电场将对其所接入的弱电网产生电压波动。本文分析了无功和电压关系以及风电场各元件的无功消耗，并讨论了风电场所使用的无功电压调节设备的特点。然后，本文综合利用静止同步补偿器快速、连续的无功调节能力和双馈风电机组的动态无功发生能力提出了一种两级无功电压协调控制策略，以实现动态补偿风电场无功，进而稳定系统节点电压。最后，本文通过算例验证了风电场无功电压控制策略的有效性，证明该策略能够抑制风速引起电压波动，系统电压跌落时能起到一定的电压支撑能力。
[Abstract]:In the face of the environmental pollution caused by the depletion of traditional fossil energy and the exploitation and utilization of energy, energy and environment have become an urgent problem for social development. Wind energy has been widely used with the advantages of large reserves, clean and renewable, etc. With the rapid development of wind power generation technology, large-scale wind farms continue to emerge. Connecting wind power to the power grid poses a major challenge to the safe and stable operation of the grid. The problem of reactive power control and voltage stability of wind power connected to power grid is the most concerned and urgent problem. Most of the new wind farms in China use variable speed constant frequency doubly-fed induction wind turbines, which have become the mainstream wind turbines in China. In this paper, the reactive power control and voltage stability of wind farm are studied for the voltage stability problem caused by doubly-fed wind farm access system. Firstly, this paper analyzes the wind speed model and the aerodynamic characteristics of the wind turbine, introduces the mathematical model of the doubly-fed induction wind turbine, and discusses the power transmission characteristics of the doubly-fed wind turbine. According to the mathematical model and power transmission characteristics, the reactive power limit of doubly-fed fan is calculated, and the operation control area and operation control mode of doubly-fed fan are analyzed. Secondly, the influence of wind turbine wake effect in wind farm is analyzed. According to the wake effect, considering the same power loss and voltage drop before and after equivalence, a dynamic equivalent calculation method of wind farm in flat area is put forward. The research method of voltage stability of grid-connected wind farm is discussed. The weak busbar of wind farm is obtained through static voltage stability analysis of wind farm. The influence of constant voltage operation mode and constant power operation mode on transient state of doubly-fed wind turbine is analyzed and discussed. Due to the randomness and volatility of the active power output with the wind speed, the reactive power emitted or absorbed by the wind farm will fluctuate with the active power output. Wind farm will produce voltage fluctuation to the weak network connected to it. This paper analyzes the relationship between reactive power and voltage and the reactive power consumption of each element of wind farm, and discusses the characteristics of reactive power and voltage regulating equipment used in wind farm. In this paper, a two-stage reactive power and voltage coordinated control strategy is proposed to realize the dynamic compensation of reactive power in wind farm by using the fast, continuous reactive power regulation ability of static synchronous compensator and the dynamic reactive power generation ability of doubly-fed wind turbine. Then the system node voltage is stabilized. Finally, the effectiveness of reactive power and voltage control strategy in wind farm is verified by an example. It is proved that the strategy can restrain the voltage fluctuation caused by wind speed and play a certain voltage supporting capacity when the system voltage drops.
【学位授予单位】：上海电力学院
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TM614

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