Abstract: To improve the quick fault clearing ability of hybrid dual-terminal HVDC transmission lines and ensure the safe operation of the transmission system,a hybrid dual-terminal HVDC transmission line longitudinal protection method based on variational mode decomposition energy entropy is proposed.Given the different voltage energy on both sides of HVDC boundary elements,and considering the fault types and the influence of transition resistance,a protection scheme of energy entropy of the voltage fault component is constructed.The voltage fault components are collected at measurement points when faults are decomposed by VMD to obtain some inherent modal components and calculate the energy entropy.The fault criteria are constructed according to the values of energy entropy of the voltage fault components in and out of the zone,and a fault pole criterion is constructed according to the ratio of the energy entropy of the components in and out of the zone.The method is verified using PSCAD/EMTDC modeling and simulation,Matlab and protection criteria.The results show that the protection method is fast,and has high reliability and strong resistance to transition resistance.