海上风电场交流并网谐波谐振放大机理分析与治理

Mechanism Analysis and Mitigation of Harmonic Resonance Amplification Caused by AC Integration of Offshore Wind Farm

由于相同电压等级下电力电缆的电容效应比架空线路大出20倍以上,使得一般在陆上风电场并网中并不严重的谐波谐振放大问题,在海上风电场并网中可能会变得十分严重,为此研究了海上风电场并网引起的谐波谐振放大问题及其治理原理。首先,对海上风电场并网时的谐波谐振放大机理进行了分析,从原理上给出了治理的技术途径;然后,以某海上风电并网实际工程为研究案例,分别建立了海上风电电网和陆上电网的谐波模型,包括电缆、变压器和风电机组的谐波模型以及超高压大电网的等效谐波模型和低压配电网的等效谐波模型,并根据所建立的谐波模型分析了发生谐波谐振放大的原因,提出了解决谐波谐振放大问题的治理方案并进行了验算;最后,对海上风电场并网引起的谐波谐振放大问题的机理和治理原理进行了总结。

Because the capacitive effect of power cables at the same voltage level is over 20 times larger than that of overhead lines,the harmonic resonance amplification problem which is not serious in the onshore wind farm integration may become very serious in the offshore wind farm integration.To this end,this paper studies the harmonic resonance amplification problem caused by the offshore wind farm integration and its mitigation principle.Firstly,the harmonic resonance amplification mechanism caused by offshore wind farm integration is analyzed,and the technical path of mitigation is given in principle.Then,taking a real offshore wind power integration project as a study case,the harmonic models of the offshore wind power grid and the onshore power grid are established,respectively,including the harmonic models of cables,transformers and wind turbines,the equivalent harmonic models of the extra-high voltage(EHV)large-scale grid and the low-voltage distribution network.According to the established harmonic models,the causes of harmonic resonance amplification are analyzed,and a mitigation scheme for solving the problem of harmonic resonance amplification is proposed and verified.Finally,the mechanism and mitigation principle of harmonic resonance amplification caused by offshore wind farm integration are summarized.