A two-stage state estimator for power systems with PMU and SCADA measurements

Recent investments in the synchrophasor technology have drastically increased the availability of phasor measurement units (PMUs) at selected substations, improving the monitoring, protection, and control of modern power systems. This paper presents a two-stage state estimation model based on measurements provided by PMUs and SCADA (supervisory control and data acquisition) system. At the first stage, a linear state estimator is formulated, using only the synchronized phasor measurements provided by PMUs. At the second stage, the estimated voltage phasors from the first stage and the SCADA measurements are simultaneously processed by a conventional non-linear state estimator to determine the whole system state. The performance of the proposed algorithm is evaluated in terms of convergence and accuracy. Simulations are conducted on the IEEE 57 and the Polish 2383-bus systems in order to validate the efficiency of the proposed algorithm.