The electricity grid was invented in the 19th century and greatly expanded in the 20th. Recognizing the grid’s complexity and relevance, the National Academy of Sciences declared the electricity system the world’s largest “machine” and placed it at the top of the list of the greatest engineering achievements of the 20th century. The challenge facing electricity systems in future is to maintain the reliable and safe operation of this ever-expanding but already complex machine.
Technological, economic, and societal needs have driven most electricity system developments. And recently, a large emphasis has been placed on the use of renewable energy resources and the electrication of transportation, both affecting future development of the grid. As a result, grid expansion is needed, but the reliability and safety challenges in an interconnected world expand as well. This concern was highlighted over the last decade by several widespread power system failures that had an enormous impact on the economy and livelihoods in both developed and undeveloped countries.