Network observability: the critical measurement identification using the symbolic Jacobian matrix

This paper presents a new method for power system critical measurement identification. A measurement is said to be critical, in an observability sense, if its removal from the measurement set leads the power system to lose observability. The proposed method is based on the analysis of the measurement Jacobian matrix structure as presented by Slutsker and Scudder (1987) (for network observability purposes). It does allow the identification of critical measurements without any calculation or even the solution of algebraic equations. It does not have a combinatory nature, being simple and fast. In order to clarify the methodology and show its simplicity, two numerical examples are provided: one illustrates how the observability analysis works; and the other shows how the proposed methodology identifies critical measurements. The proposed methodology is successfully tested using computer simulations.