Abstract: Aiming at the problems of speed, reliability, operation and maintenance in the actual application of line protection in the conventional and intelligent substation, the system architecture and technical scheme of outdoor installation line protection based on vertical integration and outdoor installation are proposed. The functions of single-bay merging unit, relay protection, intelligent terminal are vertically integrated to reduce installation amounts and varieties, simplify configuration, reduce signal transmission, and shorten the protection action time. Furthermore, this vertically integrated device is applied to provide data acquisition and control execution support to substation-area protection, security and stability device and other substation-area installations. In addition, the key techniques of outdoor installation line protection, such as synchronous sampling between substations, power-on remote control and synchronous voltage input, are researched and analyzed. The vital performances are tested and compared. Finally, the scheme is verified to be feasible and advanced through experimental results.