Abstract: This paper addresses issues such as equipment aging, functional obsolescence, and poor compatibility encountered during the long-term operation of comprehensive protection devices in 110 kV substations. It explores principles for selecting protection devices, design concepts for secondary circuits, criteria for setting parameters, and strategies for remote communication. The paper outlines key points such as the replacement of comprehensive protection devices, device commissioning, construction implementation, and control, and introduces methods for evaluating operational performance and primary performance improvement indicators. Based on a case study of the renovation of a certain 110 kV substation, the results indicate that the new devices demonstrate significant advantages in response speed, data accuracy, and communication stability, meeting the current operational requirements of substations. This lays the foundation for future intelligent upgrades such as "one-button sequential control" and remote transmission of digital meters in substations.