SVG协同DFIG机组的电压控制策略研究

Research on Voltage Control Strategy of SVG Cooperating with DFIG Unit

风电场密集并网区域长期存在电压合格率偏低的问题,根据数据显示,主要表现为部分母线电压越上限,其中一个主要原因是新能源渗透率的提高,导致其所存在的波动性明显影响了电压的稳定性。通过分析风电场并网地区电压、新能源现状以及DFIG和SVG的数学模型,并根据风电场并网结构,搭建2台发电机带有DFIG与SVG并网模型。通过对并网母线处电压偏移进行PI换算,得到所需无功补偿量,通过设计的协调无功分配策略,控制SVG与DFIG的无功补偿量,对母线电压进行精细化调控。通过改变负荷数据观察DFIG及SVG对输出节点电压和无功功率的控制效果,由此验证设计在理论上的有效性与合理性。

There is a long-term problem of low voltage qualification rate in densely connected areas of wind farms.According to the data,the main manifestation is that the voltage of some busbars has exceeded the upper limit.One of the main reasons is the increase in the penetration rate of new energy sources,resulting in the existence of volatility that obviously affects the stability of the voltage.By analyzing the voltage of the grid-connected areas of wind farms,the current situation of new energy,and the mathematical models of DFIG and SVG,and according to the grid-connected structure of wind farms,two generators with DFIG and SVG grid-connected models are built.Through the PI conversion of the voltage offset at the grid-connected bus,the required reactive power compensation amount is obtained.Under the formulated coordinated reactive power distribution strategy developed through the paper,the reactive power compensation amount of SVG and DFIG is controlled,and the bus voltage is finely regulated.By changing the load data,the control effects of DFIG and SVG on output node voltage and reactive power are observed,so as to verify the effectiveness and rationality of the design in theory.