海上风电场多采用电缆敷设或海底电缆传输,存在较大对地分布电容,而分布电容较易引起风电场谐波谐振问题。同时,风电机组工作状态及风电场参数配置都将影响系统结构及参数,进而影响系统的谐波谐振。基于此,对双馈风力发电机组建立了随风速变化的动态谐波模型。同时还建立了风电场其他主要电气元件的谐波模型,如电缆谐波模型及变压器谐波模型。然后以海上风电场为例,利用频率扫描法对公共耦合点谐振问题进行仿真分析。考虑到风电场中各部分参数对谐振的影响程度不同,利用敏感度分析方法,计算出各参数的敏感度指标,为制定抑制谐波谐振的相应措施提供了依据。
Wind power generation is currently one of the most promising renewable energy technologies. Because of cable laying and submarine transmission, large distributed capacitance exists in wind parks and it is likely to cause harmonic resonance, maybe threatening wind park safe operation. Meanwhile, operation condition of wind turbines and parameter configuration of wind parks will affect system structure and parameters, then affect system harmonic resonance. Therefore, a wind-speed-varying dynamic harmonic model of the most widely used doubly fed induction generator(DFIG) is established to study harmonic resonance. This paper also establishes harmonic models for other main electrical components in wind parks, such as cables, transformers. Simulation is carried out for an offshore wind farm, and frequency scan method is utilized to analyze harmonic resonance problem at point of common coupling(PCC). Considering impact of various parameters on resonance frequency and amplitude, sensitivity indexes for these parameters are also calculated based on sensitivity analysis and a scheme to control harmonic resonance is discussed.