Reference:
M. Picallo,
A. Anta, and
B. De Schutter,
"Comparison of bounds for optimal PMU placement for state estimation
in distribution grids," IEEE Transactions on Power Systems,
vol. 34, no. 6, pp. 4837-4846, Nov. 2019.
Abstract:
The lack of measurements in distribution grids poses a severe
challenge for their monitoring: since there may not be enough sensors
to achieve numerical observability, load forecasts
(pseudo-measurements) are typically used, and thus an accurate state
estimation is not guaranteed. However, an estimation is required to
control distribution grids given the increasing amount of distributed
generation. Therefore, we consider the problem of optimal sensor
placement to improve the state estimation accuracy in large-scale,
3-phase coupled, unbalanced distribution grids. This is a
combinatorial optimization problem whose optimal solution is
unpractical to obtain for large networks. We explore the properties of
different metrics in the context of optimal experimental design, like
convexity and modularity, to propose and compare several tight lower
and upper bounds on the performance of the optimal solution. Moreover,
we show how to use these bounds to choose near-optimal solutions. We
test the method on two IEEE benchmark test feeders, the 123-bus and
the 8500-node feeders, to show the effectiveness of the approach.