Severe icing on overhead ground wires in high-voltage direct current (HVDC) transmission systems under extremely cold climates can lead to wire breakage accidents, posing significant threats to reliable power supply. Removing overhead ground wires in ice-prone sections represents one potential solution to prevent such accidents. However, this unshielded section may increase the lightning trip-out rate of the transmission system. This study investigates the feasibility of installing externally gapped line arresters (EGLAs) for lightning protection for a typical HVDC system with overhead ground wires being partially removed. Through constructing overvoltage simulation models, this work analyzes the residual voltage, discharge current, and energy absorption levels under different arrester configurations. The findings provide reference guidelines for optimal EGLA deployment schemes.