A new dynamic state estimation approach including hard limits on control devices

This paper puts forward a comprehensive formulation for the wide area dynamic state estimation of power systems. This is a problem of great current interest in the power systems community, where significant progress has been achieved in recent years. This proposal builds on the existing work and formulates a novel approach to estimate dynamic and algebraic state variables of the entire power system in a simultaneous solution method. In contrast to existing formulations, the proposed approach simultaneously co-estimates the transient evolution of the transmission grids nodal voltages and the dynamic states associated with synchronous machines and their associated controllers. Since controllers with hard limits are always present in a power system, the proposal also estimates when and how hard limits constrain the time evolution of the power system operating state. In this case, constrained dynamic variables associated with non-windup and windup limiters are automatically handled in the estimation process by transforming the inequality constraints of hard limits into equality constraints using the complementarity theory and the Fischer-Burmeister merit function. The feasibility of the proposed method is demonstrated on the WSCC 9-bus power system and the Mexican 190-bus power system.