This paper analyzes the basic principle and function of relay protection, summarizes the common fault types, and analyzes the fault analysis methods and treatment measures combined with actual cases. Its primary role is to detect and isolate faults occurring on overhead lines or underground cables. Abstract—Short transmission lines connected in a looped configuration are typical of some industrial power systems, but they can present numerous protection coordination difficulties because of their inability to effectively use underreaching elements. The results show that the reliability of relay protection devices can be improved by means of. Abstract—This case study presents the working, testing and commissioning of the 220 kV backup distance protection schemes employed on the Pipri West Grid of Karachi Electric Limited (KEL).