Precise Synchronization of Phasor Measurements in Electric Power Systems

Phasors representing positive sequence voltages and currents ih a power network are the most important parameters i n several monitoring, control, and protection functions i n interconnected electric power networks. Recent advances in computer relaying have led to very efficient and accurate phasor measurement systems. When the phasors to be measured are separated by hundrea of miles, i t becomes necessary to synchronize the mesurement processes, so that a consistent description of the state of the power system can be established. GPS transmissions offer an ideal source for synchronization of phasor measurements. The paper describes the concept and implementation of this technique. Several uses of synchronized phasor measurements are also described. Among these are improved state estimation algorithms, state estimator enhancements, dynamic state estimates, improved control techniques, and improved protection concepts.