The results of a feasibility study to apply state estimation techniques to an electric power system are summarized. The state estimator is a digital data processing scheme which constitutes the real-time data base from which many of the central control, display, interrogation, monitoring, alarm, and logging functions derive their information. The state estimator, when included in a simulation of the sensing and telemetry subsystems, can also be used off-line to explore the design trade-offs between accuracy and cost of the information subsystem required for power system control.