Abstract: In this paper, comb the operation precautions of transmission through the bypass 2246 switching under the double-bus with bypass connection mode, and compare the operations of transmission through by-pass between lines with longitudinal distance or longitudinal direction protection (high frequency protection) and longitudinal current differential protection (optical fiber protection). Strengthening the operation methods of different protected configuration lines through comparatation, and facilitating the power special staff to master the differences between the two routing methods.