Abstract: In response to prevalent issues in rural overhead lines, such as difficulty in fault location, frequent over-zone tripping, and prolonged fault processing time, this paper takes a specific 10 kV rural power feeder in Shimenzhai, Haigang District, Qinhuangdao City, Hebei Province as a retrofitting case. It elaborates on the technical approach and implementation process of the coordinated retrofitting involving Local Feeder Automation (FA) and Time-current Differential Protection. By optimizing switch layout, reconstructing protection logic, and verifying operational performance, the project effectively addresses the pain points of over-zone tripping and expanded outage areas. The objective of preventing branch faults from affecting the trunk line and achieving self-healing for trunk faults is realized. Post-retrofitting, the fault location accuracy is refined to the "section level," and the fault isolation time is reduced to within 1 minute. The reliability of the power supply is significantly enhanced, providing reproducible practical experience for the intelligent upgrading of similar rural power grid lines.