Physics-Aware Sparse Harmonic State Estimation in Power Distribution Systems

Achieving reliable harmonic state estimation (HSE) is becoming increasingly important in smart grid development due to the growing penetration of power electronics devices, non-linear loads, and distributed energy resources. A major challenge in this field is the limited availability of power quality measurements in power distribution feeders. This inevitably results in low-observability conditions in the HSE problem, where harmonic phasors are measured at only a very few locations on the distribution feeder. We address this challenge by proposing a novel physics-aware sparse HSE method. It is built upon extracting some unique sparsity patterns in power distribution systems based on their radial topology and physical characteristics. Based on the various extracted individual and group sparsity features, we formulate and solve the physics-aware sparse HSE problem with and also without knowing the location of the harmonic source. The effectiveness of the proposed method is confirmed through multiple case studies and sensitivity analysis.