Method for improving power supply reliability of overhead network in old urban area based on primary and secondary network layering concept

The invention discloses a method for improving the power supply reliability of an overhead network in an old urban area based on a primary and secondary network layering idea. The method comprises the following steps: respectively obtaining power grid basic data of a to-be-optimized area; according to the obtained power grid basic data of the to-be-optimized area, diagnosing the line operation condition and the equipment level in the to-be-optimized area, and determining the reasonability and optimizable space of a to-be-optimized object and a grid structure, so as to perform to-be-optimized confirmation on the line in the to-be-optimized area; a branch line flexible switching system is constructed for an overhead radiation type large branch of a line in a to-be-optimized area, the overhead radiation type large branch line is optimized, a connection type secondary trunk network is constructed, and branch connection and layered operation of a primary network frame and a secondary network frame are achieved; pe