ABSTRACT
Electric power systems came into service in the 1880s and since that time have grown enormously in size and complexity. Their power generation, transmission, and distribution methods and equipment have consistently improved in performance and reliability. In practice, all communication links between equipment and the control center could be interrupted and the electric service maintained. An energy control center fulfills the function of coordinating the response of the system elements in both normal operations and emergency conditions. In extreme emergencies, such as loss of a major generator or excess power demands by a neighboring utility on the tie lines, many alarms would be detected and the system would enter an emergency state. Consistent with principles of high reliability and fail-safe features, electric utilities have almost universally applied redundancy for data acquisition from equipment in the field, and for computer control of the power system.
