—Both the communication limitation and the measurement properties based algorithm become the bottleneck of enhancing the traditional power system state estimation speed. The availability of synchro-phasor data has raised the possibility of a linear state estimator if the inputs are only complex currents and voltages and if there are enough such measurements to meet observability and redundancy requirements. The fiber optics communication network and advanced distributed computing and database technology provide the platform for fast state estimator. Moreover, the new digital substations can perform some of the computation at the substation itself resulting in a more accurate two-level state estimator. The main contribution of this paper is to propose a two-level fast linear state estimator based on the synchronized phasor measurements infrastructures. We described the layered architecture of databases, communications, and the application programs that are required to support this two...