风电场防孤岛保护策略研究

发布时间：2018-06-22 00:40

本文选题：孤岛 + 风电机组　；参考：《中国电力科学研究院》2017年硕士论文

【摘要】：传统的孤岛研究大多关注的是光伏发电系统的孤岛在线识别,目前光伏发电系统孤岛在线识别无论是理论上还是实际设备生产技术上都已经比较成熟。但人们对风电机组的孤岛保护关注很少。本文首先通过实验验证主流风电机组单机和混合系统在输出功率、电网阻抗特性变化条件下所发生的孤岛现象,分析风电机组发生孤岛运行前后输出有功、无功、电压、频率等电气量变化特性,以说明对风电机组孤岛在线识别策略研究的必要性。并且针对风电机组的孤岛问题提出一种基于无功功率扰动的适用于全功率变频风电机组和双馈风电机组孤岛在线识别方法,该方法不仅对传统注入定量无功功率扰动的方法进行了改进,并且为了解决持续注入无功功率带来的电能质量恶化问题而引入无功功率注入的触发信号——利用风电机组输出端电压信号的总谐波畸变率的变化率作为触发信号,实验及仿真结果都验证了该触发信号的可行性。并且通过仿真验证了该无功功率扰动方法应用于全功率变频风电机组和双馈风电机组能够快速对孤岛进行在线识别。然而,由于风电机组装机容量的不断增加和我国风电建设的集中式特点,此针对单机的孤岛在线识别方法应用于风电场时可能由于不同风电场间主动无功功率扰动参数的不同而导致孤岛在线识别失败,所以本文又仿真研究了更适用于风电场的阻抗孤岛在线识别方法,首先验证了主动注入谐波扰动的方法在风电场孤岛在线识别中的适用性,然后又提出一种基于谐波阻抗测量的孤岛在线识别方法,该方法对风电场并网点处电压电流不同频率的分量进行测量,并通过计算风电场并网点谐波阻抗幅值对孤岛进行在线识别。
[Abstract]:The traditional islanding research mostly focuses on the islanding identification of photovoltaic power generation system. At present, the islanding identification of photovoltaic power generation system is mature both in theory and in practical equipment production technology. But people pay little attention to isolated island protection of wind turbine. In this paper, the phenomenon of isolated island occurred in the condition of output power and power grid impedance characteristics is verified by experiments, and the active power, reactive power and voltage of wind turbine are analyzed before and after the isolated island operation. The characteristics of frequency and other electrical variables are used to illustrate the necessity of on-line identification strategy for isolated islands of wind turbines. Aiming at the islanding problem of wind turbine, a method of island identification for wind turbine and doubly-fed wind turbine based on reactive power disturbance is proposed, which is suitable for full power conversion wind turbine and doubly-fed wind turbine. This method not only improves the traditional method of injecting quantitative reactive power disturbance, In order to solve the problem of power quality deterioration caused by continuous reactive power injection, the trigger signal of reactive power injection is introduced-the change rate of total harmonic distortion rate of output voltage signal of wind turbine is used as trigger signal. Both experimental and simulation results verify the feasibility of the trigger signal. The simulation results show that the proposed method can quickly identify isolated islands in full power variable frequency wind turbine and doubly-fed wind turbine. However, due to the increasing installed capacity of wind turbines and the centralized characteristics of wind power construction in China, When this method is applied to wind farm, it may lead to the failure of islanding on-line identification because of the different parameters of active reactive power disturbance among different wind farms. So this paper simulates and studies the impedance islanding identification method which is more suitable for wind farm. Firstly, the applicability of active injection harmonic disturbance method in wind farm islanding online identification is verified. Then a method of on-line identification of isolated islands based on harmonic impedance measurement is proposed. The method measures the components of different frequencies of voltage and current at the node of a wind farm. On-line identification of isolated islands is carried out by calculating wind farm and dot harmonic impedance amplitude.
【学位授予单位】：中国电力科学研究院
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TM614

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