海上风电场集电网的高频谐振分析

Analysis on High Frequency Resonance of Collector Network in Offshore Wind Farm

大型海上风电场已经成为风力发电的发展趋势,海上风电场集电网采用电缆线路汇集电能,电缆相间电容和对地电容不可忽略,集电网的阻抗网络复杂多变,存在与风电机组阻抗交互作用进而发生高频谐振的风险,威胁到风电场的安全稳定运行。针对这一问题,构建集电网的阻抗网络,将风电场集电网等效为风电机组子系统和剩余等效风场子系统,进一步揭示了高频谐振发生的机理,研究了电缆参数、场内链式电路数量、风电机组接入台数和电网阻抗与互联系统谐振频率的变化规律。以某海上风电场系统作为研究对象,利用MATLAB软件和基于RT-LAB的控制器硬件在环仿真对该风电场进行分析,验证了理论分析的正确性。

Large-scale offshore wind farms have become the development trend of wind power generation.Submarine cables,of which the distributed capacitance cannot be ignored,are used to collect electrical energy in collector network of offshore wind farms.The impedance of collector network is complex and changeable,which will lead to a risk of high frequency harmonic resonance(HFHR) when interacting with the impedance of the wind turbine generators(WTGs).In turn,the HFHR may threaten the safe and stable operation of wind farms.To address this problem,firstly the impedance of the collector network was constructed.Furthermore,the collector network of a wind farm was divided into the equivalent wind turbine subsystem(EWTS) and the remaining equivalent wind farm subsystem(REWFS).Then,the mechanism of HFHR was revealed.The effects of cable parameters,the number of chain circuits,the number of connected WTGs,and the grid impedance on the HFHR of the interconnected system were analyzed.Taking an offshore wind farm as the research object,the MATLAB software and RT-LAB-based hardware-in-loop experiments were used to analyze the wind farm,and the results can verify the correctness of the theoretical analysis.