Distribution system state estimation using phasor measurement units

This paper presents a new methodology to solve for the state estimation problem in radial distribution networks. The state estimation process is formulated as a constrained optimization problem in which the non-monitored loads are represented by a set of bounded inequality constraints. The branch currents in rectangular coordinates are chosen as state variables. The set of measurements considered are currents and voltages from the PMUs as well as the zero current injections at the no-load buses. The objective function to be minimized is defined as the weighted least square measurements errors. The methodology is validated through simulations on some IEEE radial test feeders.