多馈入直流交互作用因子在换相失败研究中的应用

Application of multi-infeed interaction factor in South Grid commutation failure research

换相失败是直流输电的常见故障之一,单馈入直流输电系统换相失败的机理和控制策略已比较明确。但对于多馈入交直流混合输电系统,哪些故障可能引起多个换流站同时或相继换相失败甚至导致直流闭锁,是否会引起暂态失稳,还缺乏有效的研究手段。介绍了CIGRE工作组提出的多馈入直流系统交互作用评价指标——多馈入交互影响因子;探讨了该指标与多馈入直流换相失败的联系:给出了MIIF与换相失败工程判据-最小电压降落法的联系;通过仿真分析了该指标对多馈入直流系统换相失败风险评估的有效性以及与逆变站间电气距离、直流传输功率之间的关系。

Commutation failures are frequent dynamic events in HVDC system. Mechanism and countermeasures for commutation failure of single-infeed HVDC system have been made clear. But as for multi-infeed HVDC system, which faults may induce simultaneous or continuous commutation failures is still unknown for lack of effective research methods. MIIF（Multi-infeed Interaction Factor） is presented. Relationship between this factor and commutation failure in multi-infeed HVDC system is discussed. Simulations prove effectiveness of the index to evaluate risk of commutation failure and its relationship to electrical distance and HVDC transmission power is discussed.