TL;DR: In this article, the relay protection of transmission lines, transformers, busbars, etc. In this paper, the main electric wiring mode of 110kV substation is selected, the structure of substation is determined, and then the main wiring diagram is drawn. is set, and the configured protections include current quick-break protection, gas protection, and longitudinal differential protection. The application. This document supplements PJM Manual 07 which contains the minimum design standards and requirements for the protection systems associated with the bulk power facilities within PJM.