LARGE-SCALE ELECTRICITY TRANSMISSION GRIDS: LESSONS LEARNED FROM THE EUROPEAN ELECTRICITY BLACKOUTS
Swiss Federal Institute of Technology, Zurich, Switzerland
Electricity as the most versatile form of energy is the commodity of civilization, which has become something without which modern life is unthinkable. It is not a primary form of energy, but rather a secondary one, which has to be converted from various primary forms. The locations where these are available may be at distances to those where they are consumed; for example, hydraulic sources or technical constraints may require distant placements of generating stations, although primary sources would allow their site anywhere. Further, electricity requires a transport by conductors or better by transmission lines. Thus, transmission is a basic means for providing electricity to consumers. Since the transportation loss is a function of the current, the transportation over long distances is done at high voltages as high voltages allow low currents, which produce low losses. Single transmission lines are not enough as they do not guarantee enough reserves. Hence, the practice has led to the formation of interconnected transmission networks, which provide reserves, contribute to the economy of the operation and equalize between deficiencies and surplus.
The interconnection, however, implies the propagation of disturbances over wide areas. Hence, deficiencies or surplus of power are felt in the overall ...