采用多馈入交互作用因子判断高压直流系统换相失败的方法

目前对多馈入交直流受端系统的交流故障是否会导致多回直流同时换相失败的问题主要是借助于仿真工具进行分析,这种方法计算量大,并且耗时长。为此提出了一种利用多馈入交互作用因子快速判断直流系统换相失败的方法。基于节点阻抗矩阵对多馈入交互作用因子进行定义,通过最小熄弧角判断标准推导出临界多馈入交互作用因子的通用表达式,提出了基于临界多馈入交互作用因子的换相失败判断方法:某一回直流逆变侧换流母线发生三相短路故障时,如果另一回直流与该直流间的多馈入交互作用因子大于临界多馈入交互作用因子,则认为另一回直流系统也会同时发生换相失败。小算例系统和实际电网的研究结果证明了该指标和方法的准确性和有效性。

A Commutation Failure Detection Method for HVDC Systems Based on Multi-infeed Interaction Factors

At present,the problem whether the AC faults in the multi-infeed AC/DC receiving-end power grid will lead to simultaneous commutation failures of multiple HVDC transmission lines is mainly analyzed by means of simulation tools.But the calculation load of the method is large and the calculation time is long.This paper presented a fast method to determine the commutation failure of multi-infeed HVDC system instead of simulation analysis.The multi-infeed interaction factor(MIIF) based on node impedance matrix was defined and the general expression of the critical multi-infeed interaction factor(CMIIF) was derived through the minimum extinction angle criteria.A method based on CMIIF to determine commutation failure is put forward: when a three-phase short-circuit fault at the commutation bus on inverter side of one HVDC system occurs,if the MIIF between the one and another HVDC system is larger than the CMIIF,then we can know another HVDC commutation failure occurs simultaneously.The simulation results of a two-infeed HVDC test system and an actual system proved the accuracy and validity of the proposed index and the method.