A Novel Protection Scheme for HVDC Transmission Lines Based on Line Mode Current Time Warp Edit Distance

To avoid the inherent contradiction between single- and dual-ended protection, this paper proposes a novel protection scheme based on Line Mode Current Time Warp Edit Distance (TWED), addressing the insensitivity of single-ended protection for flexible DC lines under high-resistance faults and the susceptibility of dual-ended protection to interference. First, the directional and magnitude characteristics of the initial traveling wave of the line mode current during internal and external faults are analyzed, and the fault current is fitted using the Levenberg-Marquardt method. Next, wavelet modulus maxima and wavelet denoising are applied for data filtering and preprocessing of the current signal. Then, the TWED between the line mode current at the sending end and the fitted current is used to identify internal non-high-resistance faults, while the TWED between the line mode current at the receiving end and the fitted current is used to identify internal high-resistance faults, with input parameters optimized offline using the Parrot Optimizer (PO). Finally, experiment demonstrate that the proposed scheme can accurately identify internal and external faults, is unaffected by distributed capacitance, and can withstand high resistance up to 1000Ω, 15dB noise, and 20% data anomalies.