Analysis of measurement set qualitative characteristics for state estimation purposes

This paper presents a method that allows observability analysis and restoration, identification of critical measurements and critical sets as well as the updating of these measurement set qualitative characteristics in real time, based only on the network topology. The identification of critical measurements and sets is carried out in a beforehand basis, that is, they are identified using the network topology properties before running any state estimation. Making a mapping of the system states, and using information concepts, a new state space is obtained where, in a straightforward manner, the desired relationship (information) between measurements and states is obtained. The mentioned mapping and the state information are easily found via triangular factorization of the Jacobian matrix, characterizing the method as numerical. Starting from a base case measurement set, every time a snapshot of measurements has to be analyzed, only refactorization corresponding to the lost measurements has to be made. The sparse structure of such matrix allows the use of sparse techniques speeding up the process. The method was tested in the IEEE-14-bus system, IEEE-30-bus system as well as in one Brazilian real system (the 383-bus system by CHESF-Companhia Hidroeletrica do Sao Francisco). The results proved to be reliable, easy to implement and fast, showing the proposition is a useful tool for power systems real-time operation.