计及换相动态的直流换相失败在线预警方法

单一直流换相失败易引发其相邻直流同时换相失败，严重时将造成直流闭锁引发连锁故障，开展多馈入直流换相失败预警研究及预防对保障电力系统安全稳定至关重要。提出了基于预测换相电压-时间面积的多馈入直流换相失败在线预警方法。首先，通过解析直流换相过程中的交流电压、直流电流动态，实现对换相电压-时间积分面积的实时预测。其次，基于前述预测方法从单一直流系统到多馈入直流系统推导了直流输电换相失败预警系数，并对该系数的主要参数进行了整定。然后将该系数引入换相失败预防控制环节为例说明其应用方式。最后，在PSCAD/EMTDC平台中分别基于CIGRE HVDC模型及多馈入模型验证了所提直流换相失败预警系数的正确性及对换相失败预防的指导性。

Online early warning method of HVDC commutation failure considering commutation dynamics

The commutation failure of a single HVDC can easily lead to the simultaneous commutation failure of its neighboring HVDCs, which in severe cases will cause HVDC blocking and chain failures. An online warning method for multi-infeed HVDC commutation failure based on the prediction of the commutation voltage-time integration area is proposed. First, by analyzing the AC voltage and DC current dynamics during the HVDC commutation process, real-time prediction of the commutation voltage-time integration area is achieved. Second, a HVDC transmission commutation failure warning factor is derived from a single HVDC system to a multi-infeed HVDC system based on the aforementioned prediction method. Then the main parameters of this factor are determined. Third, the application of this coefficient is illustrated by introducing it into the commutation failure prevention control. Finally, the correctness of the proposed warning coefficients for HVDC commutation failure and the guidance for commutation failure prevention are verified in the PSCAD/EMTDC platform based on the CIGRE HVDC model and the multi-infeed model.