To address the issue of harmonic source localization in low-observability power distribution systems

a hierarchical localization method based on physical network structure information is proposed. Firstly

according to the physical characteristics of distribution networks

the distribution rules of harmonic voltages and currents under radial topology are analyzed. Then

measurement points are reasonably placed to partition the network and construct a new topology. Based on harmonic current path identification

the number of harmonic sources and their located sections are determined. Finally

precise estimation is carried out in the determined sections to obtain the specific locations of harmonic sources. The model is established and solved based on mixed integer quadratic programming (MIQP)

and simulations are implemented in MATLAB. Taking the IEEE 33-bus system as an example

the effectiveness and accuracy of the proposed method are verified by comparison with existing methods. The results demonstrate that the hierarchical harmonic source localization method presented in this paper can solve harmonic source localization problems that are closely aligned with real-world scenarios

achieving localization of harmonic sources in low-observability distribution systems where both the number and location of harmonic sources are unknown.