用于电力系统电磁暂态分析的风电场动态等值建模研究

Dynamic Equivalent Modeling of Wind Farms for Electromagnetic System Transient Analysis

风力发电场(WPP)的等值建模已成为分析大型风电场并网特征的重要研究手段,目前WPP的降阶模型已有文献进行研究,但是对应用于电磁暂态(Electromagnetic Transient,EMT)仿真的风力发电场等值建模还鲜有涉及。本文对应用于EMT仿真的风力发电场频率相关网络等值(Frequency dependent network equivalent,FDNE)进行研究,详细介绍风力发电场频率相关导纳矩阵的求取方法,采用一种应用于多个有理函数拟合的矢量拟合技术将上述频率响应拟合为一个FDNE,并对其进行无源性矫正,然后基于伴随电路的方法,在用于进行WPP外部电力系统EMT研究的时域仿真软件中搭建FDNE模型。本文同时提出一种表现风力发电场有源元件的低频动态特性的等值建模方法,采用更为简单的结构,并对VSC进行了明确的建模,通过仿真对比验证了该建模方法的精确性。

Equivalent modeling of wind farm(WPP)has become an important research method to analyze the grid-connection characteristics of large wind farms.Currently,there have been literatures on WPP's step-down model,but there are few studies on equivalent modeling of wind farm for electromagnetic transient simulation.This paper studies the equivalent model of wind farm frequency-related network for EMT simulation,and introduces the method of obtaining frequency-dependent admittance matrix of wind farm.A vector fitting technique applied to multiple rational function fitting was used to fit the above frequency response into a FDNE and passively correct it.Then,based on the adjoint circuit method,the FDNE model was built in the time-domain simulation software used for EMT research of WPP external power system.At the same time,an equivalent modeling method for low-frequency dynamic characteristics of active components in wind farms is proposed.The simpler structure is adopted and the VSC is clearly modeled,The accuracy of the modeling method is verified by simulation comparison.