Protective relaying is the backbone of fault detection and system isolation in high voltage (HV) power networks. As transmission systems grow increasingly complex with integration of renewables and smart technologies, the design, configuration, and application of protective relays have become more. The article provides an overview of protective relaying principles and their applications for high-voltage power system components. It covers the protection methods for generators, transformers, buses, and transmission lines using various relay types to detect and isolate faults efficiently. The relays are in round glass cases. This prevents damage to equipment, reduces downtime, and safeguards.