基于等值双馈风电场协同静止无功发生器的电网电压波动抑制策略

Voltage Fluctuation Suppression Strategy for Power Grid Based on Equivalent Doubly Fed Wind Farm Cooperative Static Var Generator

针对双馈风电机组并网后电网电压波动、传统模拟分析方法建模计算量大且频率耦合关系复杂的问题,提出一种基于等值双馈风电场协同静止无功发生器(static var generator,SVG)的电网电压稳定协同控制方法。首先,根据风电场功率特性的聚类现象提出基于K-means聚类的2步等值建模方法,分析明确了双馈感应电机(double-fed induction generator,DFIG)内定子侧和网侧变流器的最大无功补偿能力。其次,针对电网扰动情况下SVG对风电场并网点电压的支撑能力不足的问题,提出一种面向不同电压波动等级的DFIG协同SVG电网电压波动抑制策略,充分利用风电场站内部DFIG的自身无功储备,并在电压恢复过程中加入延时环节确保电压稳定。最后,通过仿真验证了所提协同控制策略对于改善风电场并网点电压波动的有效性。

In allusion to the problems of grid voltage fluctuation after a grid-connected doubly-fed wind turbine,a large amount of the modeling calculation,and the complex frequency coupling relationship of traditional simulation analysis method,a grid voltage stability cooperative control method based on equivalent doubly-fed wind farm cooperative static reactive power generator(abbr.SVG)was proposed.Firstly,a two-step equivalent modeling method based on K-means clustering was proposed according to the clustering phenomenon of wind farm power characteristics,and the maximum reactive power compensation capabilities of stator side and grid side converters in double-fed induction generators(abbr.DFIG)were analyzed and defined.Secondly,to address the issue of insufficient support capability of SVG to the voltage at wind farm connecting points in the case of a power grid disturbance,a DFIG collaborative SVG power grid voltage fluctuation suppression strategy for different voltage fluctuation levels,which makes full use of the reactive power reserve of DFIG inside the wind farm station,and adds a delay link in the voltage recovery process to ensure voltage stability,was proposed.Finally,the effectiveness of the proposed collaborative control strategy in improving the voltage fluctuation at the wind farm connecting points was verified through simulation.