Identifying external network branch status errors using synchronized phasor measurements

Errors in external network topology may have significant impact on accuracy of internal state estimation and subsequent real-time contingency analysis. Identification of any type of change in the external network topology will be impossible by using only internal system real-time measurements. However, recent availability of external system synchronized phasor measurements will facilitate identification of certain external topology errors, especially if they are strategically located with respect to the available phasor measurement units. This paper presents a practical method to identify the external line outages, using the realtime data from internal system and those external buses with PMUs. The proposed method´s performance is tested on the IEEE 30 bus system and simulation results are presented.