Optimal Placement of Power Quality Monitors for Enhanced Observability with Fewer Devices

This paper presents a power quality monitor placement method that balances observability with minimal measurement devices. The approach constructs an affinity matrix capturing how transients, harmonics, and voltage sags propagate through the network. By aggregating voltage and current data under varying thresholds, a scree-plot analysis using singular value decomposition identifies the optimal number of monitors. Tests on multiple grids demonstrate that only a few power quality monitors can capture the dominant variance. Experimental results confirm improved harmonic state estimation when voltage monitors are placed at nodes far from strong voltage sources and on less supported feeders and the opposite for current monitors. This method considers various disturbance types, downstream tasks and scales more efficiently than existing methods.