VSC阻抗频率特性检测技术研究

STUDY ON IMPEDANCE FREQUENCY CHARACTERISTIC TESTING TECHNOLOGY OF VSC

以'变流器-电网'系统的模型为基础,在控制模型及参数未知和假设条件下,基于硬件在环仿真提出用于检测直驱风电机组阻抗频率特性的方法。首先利用现场直驱风电机组控制器和实时数字仿真(real-time digital simulation,RTDS)系统搭建仿真平台,并对其参数指标进行校核;其次在电磁暂态仿真中采用扫频法和离散傅利叶变换(discrete fourier transform,DFT)得到直驱风电机组的阻抗频率特性;然后通过分析控制参数调整和运行方式变化对阻抗频谱的影响揭示风电汇集地区电网发生网络谐振的机理,并给出相应的预防控制策略;最后,通过时域仿真对本文所提方法进行有效性的验证。

This paper proposes a new method for testing the frequency impedance characteristic of direct-driven wind turbine,which using simulation with hardware in the loop.Firstly,the study utilized the direct-driven wind turbine controller and real-time digital simulation(RTDS)system to set up simulation platform,and then checked its parameters.Secondly,the paper took sweep frequency method and discrete Fourier transform(DFT)to get impedance frequency characteristic of direct-driven wind turbine.Thirdly,it revealed the mechanism of system oscillation in wind power influx area by analyzing the adjustment of parameter and the variation of operation mode.Finally,the effectiveness of the proposed methods is verified by the simulation in time domain.