中文摘要：

换相失败是直流系统逆变器最常见的故障之一,交流侧故障是其最主要的诱因。文中以换相电压时间面积为换相失败判据,在构建换相失败风险评价指标体系的基础上,提出了交流系统故障诱发多直流馈入系统换相失败风险评估方法,计及了多个不确定因素的综合作用。以南方电网2009年夏大运行方式为算例,充分验证了所述评估方法,能有效地探明诱发直流系统换相失败的薄弱环节,指导电网规划与运行维护,以减少或避免多直流系统换相失败,对保障电力系统的安全稳定运行具有现实意义和工程应用价值。

英文摘要：

Commutation failure is one of the most common faults in inverter sides of DC systems,mainly because of the AC system faults.This paper builds the commutation failure risk index system and further proposes the risk evaluation approach of multi-infeed HVDC system under AC system fault conditions considering multiple uncertain factors.The proposed approach uses the commutation voltage-time area as criterion.The case of China Southern Power Grid 2009 operation mode demonstrates that the commutation failure risk evaluation is of significant practical and engineering values to explore the weakness of commutation failure in the HVDC transmission system.It can guide planning and operation of power grid,prevent and mitigate the commutation failures,and help maintaining secure and stable operation of power systems.