Aiming at the transmission line fault in Hybrid-HVDC system, this paper divides the fault evolution process into different stages according to the difference of transition resistance at the fault point and the conduction state change of power electronic devices, emphatically analyzes the conversion conditions between different stages, and proposes an adaptive criterion for judging the moment when the fault evolves into AC feed-in stage. Based on the characteristic component of electrical quantities at AC feed-in stage, this paper defines the equivalent characteristic impedance at any point of transmission line, derives the functional relationship between the fault distance and the equivalent characteristic impedance at inverter side DC bus, and locates the fault point according to this relationship. In order to extract the characteristic component of electrical quantities, a characteristic component extraction algorithm is studied, it can effectively eliminate the influence of constant DC component and decaying aperiodic component. This paper builds the Hybrid-HVDC system simulation model and carries out simulation experiments on PSCAD/EMTDC, and compares the proposed fault location principle with the existing methods. The simulation results verify the effectiveness of the adaptive criterion for judging the AC feed-in stage starting moment and the proposed fault location principle.

针对混合高压直流输电系统的输电线路故障，根据故障点的过渡电阻的差异和电力电子设备的导通状态变化，将故障演变过程分为不同阶段，着重分析了两者之间的转换条件。阶段，并提出了一种自适应准则，用于判断故障演变为交流馈电阶段的时刻。基于交流馈电阶段电量的特征分量，定义输电线路任意点的等效特征阻抗，推导故障距离与逆变器侧直流母线等效特征阻抗之间的函数关系，并定位根据这种关系确定故障点。为了提取电量的特征分量，研究了特征分量提取算法，该算法可以有效地消除恒定直流分量和衰减的非周期性分量的影响。本文建立了混合高压直流输电系统仿真模型，并在PSCAD / EMTDC上进行了仿真实验，并将提出的故障定位原理与现有方法进行了比较。仿真结果验证了自适应判据对判断交流馈电阶段起动力矩和提出的故障定位原理的有效性。本文建立了混合高压直流输电系统仿真模型，并在PSCAD / EMTDC上进行了仿真实验，并将提出的故障定位原理与现有方法进行了比较。仿真结果验证了自适应判据对判断交流馈电阶段起动力矩和提出的故障定位原理的有效性。本文建立了混合高压直流输电系统仿真模型，并在PSCAD / EMTDC上进行了仿真实验，并将提出的故障定位原理与现有方法进行了比较。仿真结果验证了自适应判据对判断交流馈电阶段起动力矩和提出的故障定位原理的有效性。