Network observability: identification of the measurements redundancy level

In this paper, a new method to identify the redundancy level of each measurement associated to an observable power system is proposed. The proposed method also identifies the critical measurements, and sets of measurements that removed at same time from the measurement set make the power system unobservable. The redundancy level is very important to operators in order to guide the search for adequate reinforcement of the available measurement set. The proposed method is based on the linear dependency relation of the rows of the Jacobian matrix. To determine this relation, a convenient exchange of basis in the state space is made. The exploration of sparsity techniques and some adaptations make the proposed method simple and fast. This method has been tested in the IEEE-14-bus system, and in two realistic systems of the Brazilian utilities (one of them is a 121-bus system from ELETROSUL, and the other is a 384-bus system from CHESF-Companhia Hidroeletrica do Sao Francisco).