基于高比例电力电子的海上风电多端柔直系统的频率振荡抑制

Frequency Oscillation Suppression of Offshore Wind Power Multi-terminal Flexible and Straight System Based on High Proportion Power Electronics

在电压源转换器的多端高压直流(Voltage source converter-based multi-terminal high-voltage direct current,VSC-MTDC)集成海上风电场中,由于电力电子接口的渗透率较高,系统的惯量较低,其频率支撑和振荡抑制能力不足。另外,多端口间缺乏相互支援的能力,在弱电网区域受到功率波动时,频率振荡明显,这些振荡不利于可再生能源的调整和系统的稳定运行。因此,提出了一种基于VSC-MTDC的惯量和阻尼模拟控制方案,以应对海上风电场面对扰动时引起的频率波动。该方案的惯量利用直流电容进行惯性功率的模拟,阻尼利用各端口的频率进行阻尼功率的模拟,模拟的惯量和阻尼系数利用小信号模型进行了分析。最后,通过电磁暂态仿真证明了惯量阻尼方法能有效抑制VSC-MTDC系统的频率振荡,提高含有高比例电力电子接口的弱电网区域的频率稳定特性。

Due to the high penetration of power electronic interface and the low inertia of the integrated offshore wind farms of voltage source converter-based multi-terminal high-voltage direct current(VSC-MTDC),its frequency support and oscillation suppression capacity are insufficient.At the same time,due to the lack of mutual support between multiple terminals,the frequency oscillation of offshore wind power system is obvious when the weak grid area is subject to power fluctuations,which is not conducive to the adjustment of renewable energy and the stable operation of the system.Therefore,an inertia and damping simulation control scheme based on VSC-MTDC is proposed to deal with the frequency fluctuation caused by the disturbance of offshore wind farm.The proposed inertia uses the DC capacitance to simulate the inertia power and the frequency of each port to simulate the damping power,and the inertia and damping coefficients of the simulation are analyzed using small signal model.The electromagnetic transient simulation shows that the inertia damping method can effectively suppress the frequency oscillation of VSC-MTDC system and improve the frequency stability characteristics of the weak current network area with a high proportion of power electronic interfaces.