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Keywords

three-phase imbalance; low‑voltage distribution network; impedance identification; hierarchical deconstruction; phase recursion

Abstract

The large-scale integration of distributed photovoltaics and electric vehicles exacerbates the three-phase imbalance in low-voltage distribution network (LVDN), which further leads to issues such as current in neutral wire and voltage fluctuations, preventing the simplification of three-phase line impedance identification into three independently solved single-phase networks with unified power flow. For this reason, a set of line impedance identification methods based on hierarchical deconstruction and phase recursion are proposed, addressing the issue of neutral line current imbalance using the principle of child node voltage correlation. Firstly, three layers are obtained through hierarchical deconstruction: the substation layer, branch layer, and user layer, with each layer having its internal node connected to the subnetwork. A voltage matching model is then constructed for the phase line to retrace the branch layer’s line. Next, a node power-checking model is used to estimate the node phase angle in the substation layer. The neutral line parameter is recursively derived according to the electrical vector relationship, and errors in the recursion process are minimized to obtain the line impedance identification results. Finally, the effectiveness and accuracy of this method are verified through actual system and load data.

DOI

10.19781/j.issn.1673-9140.2025.02.014

First Page

131

Last Page

140

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