Decentralized multi-area state estimation with hybrid measurements

Power system state estimation (SE) is one of the most fundamental applications at the control center, since it helps the system operator to monitor, control and optimize the performance of the power grid. Motivated by the advancements in synchronized phasor measurement units (PMU) and the urgent need of a better state estimator to address the corresponding system complexity and computational burden, we focus on a potential solution for the state estimation: decentralized multi-area state estimation (MASE) with synchrophasor measurements. A synchrophasor-assisted hybrid MASE algorithm has been proposed to tackle this problem, where the boundary bus state estimates generated from the tie-line based synchrophasor-only linear SE are transformed into the equality constraints imposed upon the local SE in each area. This strategy takes full advantage of the linear model resulted from PMU measurements and reduces the size of the non-linear system to be solved in state estimation and hence the complexity. Numerical simulations have been implemented in the IEEE 14-bus system, and the simulation results show that the proposed algorithm can not only provide system state estimates with good accuracy, but also can speed up the computational process of SE for the entire system.