Reduced model for numerical observability analysis in generalised state estimation

This paper deals with the problem of observability analysis in generalised state estimation, which models selected substations at the physical level (busbar-section/switching-device model). The generalised state estimator is an extension of the conventional state estimator, which incorporates the active and reactive power flows on circuit breakers as state variables. The status of a circuit breaker can be open, closed or unknown. For the formulation of the observability analysis problem, a reduced network is used, according to the circuit breaker statuses provided by SCADA. Based on this reduced network, observability testing and measurement placement are accomplished by a numerical approach. The method is illustrated with a 20 node system