The invention discloses a voltage configuration scheme for switchable maintenance of a busbar merging unit of a double-busbar connection mode 110kV system of an intelligent substation. All 100kV interval merging units and bay level secondary equipment are added to an optical cable loop of a 110kV II section busbar merging unit, and all 100kV interval merging units and bay level secondary equipment are connected to an output optical port of the 110kV II section busbar merging unit through a newly added optical cable loop, so that when any busbar PT merging unit fails, substation operation and maintenance staff switch all intervals to another busbar to operate through a busbar switching operation to ensure that all intervals still operate normally, and then inform repair and maintenance staff to check and treat to the site. The maintenance of any busbar PT merging unit can also be arranged in a busbar switching mode, so that the stop of operating equipment is avoided.