This paper describes a new approach that led to the development of a fully distributed state estimator, named the SuperCalibrator (SC). The SC is a three-phase state estimator that operates at the substation level and requires at least one PMU at each substation. The computed substation state estimate is transferred to the control center where the overall system state is synthesized from the substation states. The SC-based distributed state estimator has been implemented on the US Virgin Islands St. Thomas and St. John power system of the USVI Water and Power Authority. The most significant performance characteristics of the system are: (a) High update rate up to four system wide state estimation solutions per second, (b) High Accuracy - typically 0.05 degrees in phase and 0.1% in magnitude, (c) Scalability, (d) No need for tuning of the state estimation process.