Decentralized PMU-assisted Power System State Estimation with Reduced Inter-Area Communication

In this paper, we present a decentralized approach to hybrid, multi-area power system state estimation, i.e., state estimation using both conventional RTU measurements and newer PMU measurements. We employ a reduced-order approach to hybrid state estimation, wherein the PMU observable and unobservable components of the state vector are estimated separately in each control area. The estimation problem is solved by exchanging information through a gossip-based protocol which takes into account the weak measurement coupling between control areas. A detailed analysis of this protocol reveals that the amount of information exchange is always less than the naive gossip based scheme. We show through simulations on the IEEE 118-bus test system that in practice, the gossip iterations converge in one iteration regardless of the number of control areas. Our simulations also show that the marginal information exchange is also considerably lower when using the proposed method.