Journal of Critical Infrastructure Policy
Figure 1 . Electric Grid Generation , Transmission , Distribution , and Customers Graphic credit : U . S . Department of Energy
Figure 2 . Interconnections of the North American Electric Grid Graphic Credit : U . S Department of Energy
Within the U . S . portion of the interconnections , twelve master control rooms and several thousand subsidiary control facilities manage the operation of equipment at nearly 70,000 transmission and distribution substations . This farflung control system is made possible by long-haul communications owned by both utilities and common carriers . The Canadian portion of the North American electric grid uses a similar system of control .
Communication technologies used in the U . S . electric grid principally include fiber optics , microwave radio , and copper conductor circuits . Utilities commonly rely on a mixture of company-owned circuits and circuits leased from common carriers . Communication systems of large , investor-owned utilities often consist of microwave and fiber optic networks . Smaller utilities , usually municipal
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