【摘要】 随着高压直流输电技术在远距离、大容量输电中的广泛应用，LCC-HVDC因其独特优势而备受关注。然而，LCC-HVDC系统采用的半控型器件缺乏自关断能力，故障时容易发生换相失败，会对系统的稳定性和安全性有较大影响。鉴于此，文中研究了LCC-HVDC系统的动态换相过程，详细分析了正常运行与交流系统故障下换流变压器阀侧电流的变化特性，并提取了此电流的变化特征。在此基础上，基于其不对称性特征构建一种LCC-HVDC系统换相失败检测判据，以快速、准确地检测多次换相失败的发生。最后，基于PSCAD/EMTDC仿真平台，采用CIGRE LCC-HVDC系统仿真模型及实际的同塔双回线模型对该方法在不同运行条件下的有效性进行了验证。实验结果表明，所提出的判据在多次换相失败的检测中具备快速响应能力和较高的检测精度，表现出良好的可靠性和鲁棒性，可以为实际工程中换相失败的检测提供理论参考。更多还原

【Abstract】 With the widespread application of HVDC transmission technology in long-distance and large-capacity power transmission, line-commutated converter based high voltage direct current(LCC-HVDC) attracts much attention due to its unique advantages. However, the semi-controlled devices used in LCC-HVDC system lack self turning off capability, and commutation failure is easy to occur in case of fault, which greatly affects the stability and safety of the system. Therefore, the dynamic commutation process of LCC-HVDC system is researched, the variation characteristics of the valve-side current of the converter transformer under normal operation and AC system faults are analyzed in detail, and the variation features of this current are extracted. On this basis, a commutation failure criterion of LCC-HVDC system is proposed based on its asymmetry characteristics, enabling rapid and accurate identification of multiple commutation failures. Based on the PSCAD/EMTDC simulation platform, the effectiveness of this method under various operating conditions is verified by means of simulation models of CIGRE LCC-HVDC system and practical double-circuit transmission lines models on the same tower. The experimental results indicate that the proposed criterion has fast response and high detection accuracy in multi-commutation failure scenarios, demonstrating strong reliability and robustness, and providing a theoretical reference for the detection of commutation failure in practical engineering applications.更多还原