Two-level state estimation method for power systems with SCADA and PMU measurements

This paper proposes a two-level hybrid state estimation method for power systems with SCADA and PMU measurements. A power system is decoupled into PMU observed areas and SCADA observed areas based on its system measurement configuration and topology connectivity, and the states of areas are solved by a two-level computational procedure. The first level uses PMU measurements and pseudo measurements derived from SCADA measurements to formulate a linear state estimation model for each PMU observed area, from which the states of the buses in the area are estimated. The second level uses the SCADA measurements and pseudo measurements generated by results at the first level to formulate a nonlinear state estimation model for each SCADA observed area. The weighted least square method is used to solve the models at the two levels. Test results on an IEEE 14 bus system and an IEEE 118 bus system are given to demonstrate the effectiveness of the proposed method.