【摘要】 高压直流输电系统的谐振问题影响范围大、危害严重，已成为本领域研究的重点问题。特别是基于模块化多电平换流器的高压直流（MMC-HVDC）输电系统虽具有多项优点，但也带来了中高频谐振问题，严重影响电网的安全稳定运行。因此，为了对中高频谐振问题进行分析，通过模块化的思想提出了MMC-HVDC输电系统谐振分析等效模型。首先，将MMC-HVDC输电系统分块为直流电网、交流电网和MMC；然后计及锁相环控制、功率与电压外环控制、电流内环控制等环节和控制链路延时，通过阻抗法建立MMC交直流两侧的等效模型，并考虑线路分布参数特性，建立线路模型；并根据交直流系统连接关系，构建MMC-HVDC系统等效电路模型；最后通过仿真软件搭建MMC-HVDC输电系统模型，完成模型验证。结果表明：相对于目前复杂的模型和不完整的交直流系统分析，所提模型考虑了中高频主要影响因素，不仅简化了模型复杂度，而且具有较高精度，计算误差小于5%。此外，由于影响因素不同，直流阻抗与交流阻抗具有不同的频率特性。更多还原

【Abstract】 Resonance issues in high-voltage direct current(HVDC)transmission systems exhibit extensive impact ranges and severe hazards,making them a critical research focus in this field. Particularly,although modular multilevel converter-based HVDC(MMC-HVDC)systems possess multiple advantages,they introduce medium-and high-frequency resonance problems that significantly threaten the secure and stable operation of power grids. To analyze these resonance issues,an equivalent model for resonance analysis in MMC-HVDC transmission systems is proposed using a modular approach. First,the MMC-HVDC transmission system is partitioned into the DC grid,AC grid,and MMC.Subsequently,considering key factors including control units of phase-locked loop(PLL),power outer loop,voltage outer loop,current inner loop,and control loop delays,impedance-based equivalent models are developed for both AC and DC sides of the MMC,and transmission line models are developed through the integration of distributed parameter characteristics. Subsequently,a holistic network representation of the MMC-HVDC system is formulated by synthesizing AC and DC systems. Finally,an MMC-HVDC transmission system model is implemented in simulation software for validation. The results demonstrate that compared with existing complex models and incomplete AC/DC system analyses,the proposed model incorporates major medium-and high-frequency influencing factors. This approach not only simplifies model complexity but also achieves high accuracy with calculation errors below 5%. Furthermore,distinct frequency characteristics are observed between DC and AC impedances due to different influencing factors.更多还原