Protective relays are devices that detect abnormal electrical conditions—such as overcurrent, overvoltage, or faults—in power systems and immediately initiate actions to isolate affected sections. They help safeguard generators, transformers, motors, feeders, and other equipment, ensuring safety and stability. Modern versions are often digital or numerical, offering real-time monitoring, remote control, diagnostic features, and better integration with smart grid systems. The shift from legacy electromechanical relays toward smarter, more connected protection solutions is gaining momentum as power networks modernize, renewables are added, and reliability demands increase.