Research on PMU/SCADA mixed measurements state estimation algorithm with multi-constraints

Since the actual status of coexist of supervisory control and data acquisition system (SCADA) and phasor measurement unit (PMU), precision of traditional power system state estimation without PMU phasor is low. A new algorithm based on PMU/SCADA mixed measurements is proposed. Constraints of zero-injection nodes and PMU measurements are taken into estimation equation, and the optimal estimation under double constraints can be derived by optimization theory of Lagrange multipliers method. Simulation results of ship integrated power system show that multi-constraints of mixed measurements are fully utilized in this algorithm, precision of state estimation is improved significantly and real-time can also be guaranteed within a certain range.