Half-wavelength alternating current transmission line（HWACTL） has been drawing attention all over the world due to its remarkable economical and technological advantages. In addition to introducing the operating characteristics of HWACTL， its voltage and current distribution is also discussed. Equations describing the secondary arc current and the recovery voltage of HWACTL are given through building up electromagnetic coupled model of transmission line. Furthermore， the impacts of transmission power， man-made tuning network and line length， etc. on the secondary arc current and the recovery voltage are investigated in comparison with typical short lines. The uneven optimal arrangements of high speed grounding switch（HSGS） along the transmission line are studied in order to cut down the secondary arc current and therefore shorten the arcing time. An optimized HSGS arrangement is proposed and validated with a dynamic secondary arc model in detail. Finally， the optimal time sequence for single-phase auto-reclosure scheme of HWACTL with HSGS is put forward.