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在线路行波类测距方法中，存在行波到达时刻与行波传播速度难以有机统一的问题。在研究直流线路故障行波速度与行波到达时刻的特定瞬时频率关系的基础上，分析瞬时频率影响行波测距的机理，提出一种基于行波瞬时频率且波头到达时刻与波速相有机统一的故障测距思想。利用改进的希尔伯特–黄变换形成故障暂态信号的时频图，依据时频图标定行波到达时刻与该时刻特定的瞬时频率，再经由瞬时频率求取相应的波速度，形成高压直流线路故障测距实用算法。在PSCAD软件上进行的仿真测试，表明所提测距方法及其算法受过渡电阻、故障类型影响较小，不同故障距离下测距精度都较高，也得到了现场实测数据的验证。“,”In the transmission line fault location based on traveling wave, the organic unity between the arrival time of the traveling wave and the wave speed is a serious problem. The relationship of instantaneous frequency and the wave speed was analyzed. On the basis, a novel traveling wave fault location algorithm for HVDC transmission lines was proposed, in which the organic unity of the arrival time of wave-front and wave speed was considered. The improved Hilbert-Huang transform was used to obtain the time frequency diagram, through which the arrival time of the traveling wave and the instantaneous frequency was determined. Then the wave speed was obtained by the corresponding instantaneous frequency. The algorithm has been performed for a large amount of simulation cases in PSCAD. Results show that the proposed method is independent to transition resistance and fault type, and the fault location accuracy is high at different fault distance. This algorithm is also verified by field-recorded data.