Protection — Evolution, Technologies and Trends

Industrial growth with increased automation has made electricity as the key resource for the modern society. Electric power in today’s context has assumed importance as necessity of life next to food, shelter and clothes. This also implies that all elements of entire chain of power generation, transmission and distribution needs to offer fail safe performance at all instance of time, and in case of any unforeseen faults, are required not only to provide effective protection to power system elements and isolate the fault but also ensure continuity of electric supply for rest of network, by ensuring very minimal region/loads over faulted section remains without power. Power system protection hence remains one of the most complex discipline in electrical engineering. Protective relays are the decision-making devices in the protection scheme. These relays have undergone, through more than a century, important changes in their architecture, functionalities and technologies. In this paper, after giving insight on the evolution of protective relays from onset of electrical energy to current deployment, emerging trends are also touched upon. Specific emphasis on very recent deployment of Centralized Protection and Control solution is then described. Finally, future trends are also highlighted at the end.