Fault location is crucial for the long-distance HVDC transmission systems.Here,a fault location model using the Improved Pelican Optimization Algorithm (IPOA) to optimize the Least Squares Support Vector Machine (LSSVM) is provided to address the issues of imprecise attenuation coefficient computation and challenging secondary wave head capture.First,in accordance with the traveling wave attenuation concept,the formulas of the fault distance and the modulus maximum ratio of the line mode components at both ends of the line are derived,revealing a nonlinear relationship between them,which is then generalized by LSSVM.Second,the IPOA is employed to optimize the key parameters of LSSVM,thereby constructing the IPOA-LSSVM fault location model.After performing wavelet transform on the fault signals collected at both ends,the amplitude ratio of the first wave head is obtained and then input into the proposed model to output the fault distance as simulation verification.Simulation results show that the proposed model can locate fault reliably and accurately regardless of transition resistance and fault type.