风电场接入高压直流受端系统对换相失败的影响分析

Impact of Wind Farm Integration into HVDC Receiving-end System on Commutation Failure

  • 摘要: 大规模风电场接入高压直流受端已经成为重要应用场景,风电场对高压直流换相失败的影响是系统安全稳定运行中需要考虑的重要问题。从风电机组的低电压穿越控制和锁相环控制两方面研究了风电场接入高压直流受端系统对换相失败的影响。首先,建立计及电压跌落和谐波畸变影响的换相面积裕度,提出基于该换相面积裕度的换相失败识别方法;然后,分析风电低电压穿越控制可以提升电压支撑能力,有利于改善换相失败过程;并且,揭示了风机网侧锁相环带宽较大时,系统将产生较大的二次谐波电压,会恶化高压直流换相失败的机理;最后,在PSCAD/EMTDC仿真平台验证所提理论的正确性。

     

    Abstract: The integration of large-scale wind farms into HVDC receiving terminals has become an important application scenario. The impact of wind farms on HVDC commutation failure constitutes a critical issue for the safe and stable operation of the system. In this paper, we investigate the impact of wind farm connection to the HVDC receiving end system on commutation failure from two aspects: low-voltage ride-through control and phase-locked loop control of wind turbines. Firstly, a commutation area margin that accounts for the effects of voltage drop and harmonic distortion is developed, and a commutation failure identification method based on this commutation area margin is proposed. It is subsequently analyzed that low voltage ride-through control of wind power can enhance the voltage support capability, which is beneficial for improving the commutation failure process. It reveals that when the bandwidth of the phase-locked loop on the wind turbine grid side is large, the system may generate a larger second harmonic voltage, which will exacerbate the risk of HVDC commutation failure. Finally, the correctness of the proposed theory is validated through simulations on the PSCAD/EMTDC simulation platform.

     

/

返回文章
返回