混合多馈入直流输电系统谐波交互作用强度的评估方法

An Assessment Method on Harmonic Interaction Analysis of Hybrid Multi-Infeed HVDC System

为了分析混合多馈入直流输电系统中各换流站交流侧谐波交互影响机理,建立了混合多馈入直流输电系统的谐波阻抗模型,提出了谐波交互作用因子(harmonic multi-infeed interaction factor,HMIIF)作为评估谐波交互作用强度的方法。基于谐波阻抗矩阵的分析结果表明,LCC-HVDC对MMC-HVDC的谐波交互作用规律与LCC-HVDC之间规律基本相同。LCC-HVDC对MMC-HVDC的谐波交互作用与MMC换流器交流侧谐波阻抗相关,且随等效联络阻抗减小而增强;当其中一回直流所联结交流系统等值谐波阻抗越大,该回直流对其他回直流交互作用越强,其他回直流对其交互作用越弱。HMIIF与两回直流间的谐波交互作用强度成正比。最后利用PSCAD/EMTDC建立三馈入直流输电系统简化模型。

In order to analyze the receiving-end AC side's harmonic interaction mechanism of the converter station in the hybrid multi-infeed HVDC transmission system,the harmonic impedance model of hybrid multi-infeed HVDC transmission system is established.Harmonic multi-infeed interaction factor(HMIIF)is proposed to measure harmonic interaction.The results of analysis based on the harmonic impedance matrix show that,the law of harmonic interaction between LCC-HVDC and MMC-HVDC is basically the same as that between different LCC-HVDC systems.The harmonic interaction between LCC-HVDC and MMC-HVDC changes with the harmonic impedance of MMC's converter in the AC side and it increases with the decreases of the coupling impedance between DC placements;the harmonic interaction of other DC systems to a certain DC decrease with the growth of the DC's equivalent harmonic impedance of AC subsystems;the harmonic interaction of this DC system to other DCs increases with the growth of the DC's equivalent harmonic impedance of AC subsystems.The index HMIIF and harmonic interaction between two DC systems are inversely proportional relationship.Finally,The simulation results of a hybrid three-infeed HVDC transmission test system built by PSCAD/EMTDC verify the correctness of the conclusions.