Explore the evolution of protective relays from 1880s electromechanical designs to today's smart relays with AI. Learn about key milestones from ABB, Siemens, and PILZ in overcurrent, distance, and digital protection technologies. Eng, IEEE Life Fellow IEEE/IAS/I&CPSD Protection & Coordination WG Chair Jacobs Canada. A Power System consists of various electrical components like Generator, transformers, transmission lines, isolators, circuit breakers, bus bars, cables, relays, instrument transformers, distribution feeders, and various types of loads. In 1901, the induction-type overcurrent relay was introduced, followed by ASEA (now ABB) launching the first time-delay overcurrent relay, TCB, in 1905, enabling graded protection.