The converter station is a crucial node in the AC/DC hybrid power grid and has complex fault characteristics. Traditional protection methods based on power frequency components may not respond accurately to faults on the converter station's AC outlet, owing to converter station fault characteristics. This paper proposes a new directional element based on the R-L model time-domain differential equation algorithm and the difference in fault current characteristics between both ends of the AC outlet of the converter station. In the case of a short-circuit fault on the AC line out of the inverter station, there is a significant difference in the fault current characteristics supplied by the DC system side and the receiving AC system. By calculating the correlation between the measured and calculated voltage drop, the proposed directional element can accurately discern the fault direction. Analysis indicates that the proposed directional element is applicable to the line protection of the AC line out of the inverter station and can function correctly even when the converter station only has one line out. Simulation results reveal that this directional element exhibits excellent protection performance, unaffected by factors such as lightning strikes, fault types, and phase-change failures at the inverter station.