Application of the undetectability index to design reliable metering systems for bad data processing

This paper presents a new insight to design reliable metering systems for state estimation purposes based on the Undetectability Index (UI). Gross errors in measurements with high UI are very difficult to be detected by methods based on the analysis of the Weighted Least Squares (WLS) state estimator residuals. This paper explores the information provided by UI to design metering systems more reliable for gross errors processing. The idea is to obtain observable metering system, absent of both critical measurements and critical sets, formed by measurements with UI lower than a pre-specified value. This paper also presents the necessary theoretical concepts and a very simple algorithm to compute the UI of all available measurements in a metering system, as well as, the results of some computer simulations with IEEE-14 and 30 bus systems.