远海风电场经VSC-HVDC联接弱受端系统的临界运行特性

基于电压源变流器型的高压直流输电(VSC-HVDC)是远海风电场的常用并网方式,同时可用于联接弱受端系统,但接入后的运行特性还有待研究。该文建立了远海风电场经VSC-HVDC联接弱受端系统模型,基于安全稳定运行约束条件,以短路比(SCR)作为受端系统强弱的判定指标,充分考虑了双馈风机(DFIG)无功控制方式和受端系统阻抗角的影响,得出不同风电场出力对应的临界短路比(CSCR)。在DIgSILENT/ PowerFactory软件中进行风速波动小干扰和暂态稳定性仿真,结果表明以双馈风机作为发电机模型联接的弱受端系统短路比大于1.6为宜,并给出降低临界短路比的补偿措施,对实际工程有一定的指导作用。

Critical Operation Characteristics of Offshore Wind Farm Integrated to Weak Receiving Systems by VSC-HVDC

Voltage source converter HVDC (VSC-HVDC) is a commonly used grid integration scheme for the offshore wind farm, and can be used to connect weak receiving systems. It is necessary to study the operation characteristics after integration. Therefore, the simulation models are established for the offshore wind farm integrated to weak receiving systems by VSC-HVDC. Based on the steady-state and stability security constrains, the paper considers the reactive power control scheme of the doubly fed wind induction generator (DFIG) and the influence of receiving systems impedance angle, and take the short circuit ratio (SCR) as the evaluation indicator of the receiving systems. And the critical short circuit ratio (CSCR) is obtained based on the different wind farm output. Then the the static stability with wind speed fluctuations as the disturbance and transient stability are simulated on the platform of DIgSILENT/PowerFactory. The results show that the SCR should be more than 1.6 when DFIG as the generator is integrated to weak receiving systems. At last, some compensation measures are given to reduce the CSCR, which can provide the guidance to actual projects.