Improving State Estimation With Real-Time External Equivalents

Reduced external networks supplied with real-time data are employed in this paper to solve the state estimation problem in interconnected systems. We propose a method to obtain a composed single system state of different monitored areas with local estimations and external equivalent models, which neither require the use of a coordination agent nor requires extensive data interchange. Phasor measurement unit (PMU) measurements taken from system boundaries are used to provide updated equivalent networks as well as an inter-area synchronism. The approach allows testing erroneous external models directly in the state estimation framework. The detectability of bad data in interconnection measurements are also preserved. Tests with the IEEE 118-bus and IEEE 300-bus systems show robustness and accuracy of the model under different area decomposition schemes with low computational requirements compared to similar conventional approaches.