直驱风电场经柔性直流输电并网的宽频振荡特性分析

Broadband oscillation characteristics analysis of a VSC-HVDC connected direct drive wind farm

随着可再生能源渗透率的提高,电力系统中电力电子装置不断增加,装置间相互影响会诱发频率从几赫兹到数千赫兹范围内的宽频振荡。针对直驱风电场(Direct-Drive Wind Forms,DDWFs)经柔性直流输电(Voltage Source Converter based High Voltage Direct Current,VSC-HVDC)并网引发的宽频振荡问题,基于DDWFs经VSC-HVDC并网系统动态数学模型,建立了小信号模型与阻抗模型。进而采用特征值分析法对振荡模式进行了分析,并验证了“负电阻”理论在该系统宽频振荡机理分析中的适用性。最后结合特征值分析法和阻抗法全面分析了参数变化对振荡特性的影响,并利用PSCAD/EMTDC验证了上述分析的正确性。结果表明,可以基于特征值分析法和阻抗法进行参数调整以减小宽频振荡幅值。

With the increase of the permeability of renewable energy,the number of power electronic devices in the power system is increasing,and the interaction between the devices will induce broadband oscillation in the frequency range from a few to thousands of Hz.There is a problem of broadband oscillation caused by direct-drive wind farms(DDWFs)connected to the grid via a voltage source converter-based high voltage direct current(VSC-HVDC).To help solve this small signal and impedance models are established based on the dynamic mathematical model of the VSC-HVDC grid-connected system with DDWFs.Then,the oscillation modes are analyzed by eigenvalue analysis and the applicability of"negative resistance"theory in the analysis of the broadband oscillation mechanism of the system is verified.Finally,the influence of parameter changes on oscillation characteristics is comprehensively analyzed using eigenvalue analysis and the impedance method,and the correctness of the above analysis is verified by PSCAD/EMTDC.The results show that parameters can be adjusted based on eigenvalue analysis and the impedance method to reduce the amplitude of broadband oscillation.