海上风电场直流并网系统小扰动稳定分析

Analysis of Small Disturbance Stability of DC Grid-Connected System on Offshore Wind Farms

利用静止同步补偿器提高系统的振荡阻尼,详细推导静止同步补偿器的数学模型,并在双闭环控制环节的基础上提出一种改进的提高系统振荡阻尼的方法,将同步发电机的转速差信号引入到静止同步补偿器的控制系统中,使静止同步补偿器输出与系统振荡相关的阻尼功率,减小系统在发生故障时功率振荡的幅度和时间.基于DIg SILENT建立双馈感应风力发电机、电压源变流器(VSC)、标准三机9节点系统的仿真模型.通过特征值分析法和时域仿真法对系统进行验证,均有效验证了改进方法能够提高系统的阻尼,增强系统在发生扰动时稳定性.

Oscillation damping of DC grid-connected system on offshore wind farms can be improved by using a static synchronous compensator （STATCOM） . The mathematical model for static synchronous compensators is deduced in detail. Based on double closed-loop control strategy, an improved method to improve the oscillation damping of the system is proposed. The speed difference signal of the synchronous generator is introduced into the STATCOM control system. This method allows STATCOM to output the damping power associated with the system oscillation and to reduce the amplitude and time of the power oscillation in the event of a fault. This paper builds a circuit model for DFIG, voltage source converter, standard three-machine 9-nodes system based on DIgSILENT/Power Factory. The new method is verified by eigenvalue analysis and time domain simulation. Both of the analytical methods can verify that the new method is able to improve the damping of the system and reduce the oscillation of the system when disturbance occurs.