Paper Title
Different Protection Scheme for Complex Power System

Abstract
The present scenario of the modern power network has obligated protection system to perform better. This chapter aims to provide the reader why power system protection is so important. It examines open‐ and short‐circuits faults, shows different protection zones, explains the operational philosophy of primary and backup relays, lists the design criteria that should be considered during designing protection schemes, introduces overcurrent relays with their types and sub‐types, and covers some case studies. Any electric power system consists of three principal parts: power generation, power transmission, and power distribution. In order to make protection designs adequate, power systems are divided into multiple zones where each zone can be individually protected against its corresponding faults. Good protection system designs can be created if each zone has a number of primary and backup relays. The designed protection scheme can be accomplished in several ways with different complexities and options. Fuses can be considered as the oldest protective devices that are used nowadays. Keywords - FACTS, Distance Relay, Protection System, Differential Relay, Transmission Line