Open Access

ARTICLE

Impedance Reshaping Based Stability Analysis and Stabilization Control for Flexibly Interconnected Distribution Networks

Yutao Xu¹, Zukui Tan¹, Xiaofeng Gu¹, Zhuang Wu², Jikai Li^2,*, Qihui Feng¹
1 Electric Power Research Institute of Guizhou Power Grid Co., Ltd., Guiyang, 550002, China
2 XJ Electric Co., Ltd., Xuchang, 461000, China
* Corresponding Author: Jikai Li. Email:
(This article belongs to the Special Issue: Construction and Control Technologies of Renewable Power Systems Based on Grid-Forming Energy Storage)

Energy Engineering https://doi.org/10.32604/ee.2025.071243

Received 03 August 2025; Accepted 09 October 2025; Published online 12 November 2025

Abstract

Flexibly interconnected distribution networks (FIDN) offer improved operational efficiency and operational control flexibility of power distribution systems through DC interconnection links, and have gradually become the main form of distribution networks. Aiming at the impact of constant power loads and converter transmission power variations in FIDN system stability, this paper presents an impedance reshaping based stability analysis and stabilization control to enhance the stability of the interconnected system and improve the system’s dynamic load response capability. Firstly, a small-single based equivalent impedance model of FIDN system, which consists flexibly interconnected equipment, energy storage, PV units, and constant power loads, is presented, and the total output and input impedance of the DC distribution network are derived. Secondly, the impacts of constant power loads and transmission power variations on the small-signal stability of FIDN system are analyzed through Nyquist stability curves using the impedance ratio criterion. Then, an impedance reshaping-based stability enhancement strategy for the FIDN system is proposed, which can significantly improve the system stability under the operating conditions of constant power loads and transmission power variations. Finally, a MATLAB/Simulink simulation model is built and tested. The results demonstrate that the proposed impedance reshaping strategy effectively mitigates voltage dips, surges, and DC bus fluctuations, shortens transient responses under power variations, and enables rapid stability recovery with reduced voltage drop during severe AC sags.

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Keywords

Stability analysis; low-voltage AC/DC distribution areas; stabilization control

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