Open Access

ARTICLE

Load Balancing Control Strategy for Multi-Substation Flexible Interconnection Distribution Networks Considering Unbalanced Power Compensation

Qiji Dai¹, Jikai Li^2,*, Bohui Ning¹, Yutao Xu¹, Chang Liu², Xuan Zhang¹

1 Electric Power Research Institute of Guizhou Power Grid Co., Ltd., Guiyang, 550002, China
2 XJ Electric Corporation, Xuchang, 461000, China

* Corresponding Author: Jikai Li. Email:

(This article belongs to the Special Issue: Emerging Technologies for Future Smart Grids)

Energy Engineering 2025, 122(10), 4061-4080. https://doi.org/10.32604/ee.2025.067304

Received 29 April 2025; Accepted 04 July 2025; Issue published 30 September 2025

Abstract

Aiming at the challenge of complex load balancing coordination for a three-phase four-leg (3P4L) based multi-ended low voltage flexible DC distribution system (M-LVDC) considering unbalanced power compensation, this paper proposes a phase-split power decoupling unbalanced compensation strategy based load balancing strategy for 3P4L based M-LVDC. Firstly, the topology and operation principle of the 3P4L-based M-LVDC system is introduced, and quasi-proportional resonant (QPR) based phase-split power current control for the 3P4L converter is proposed. Secondly, a load-balancing control strategy considering unbalanced compensation for 3P4L-based M-LVDC is presented, in which the control diagrams for each 3P4L-based converter are detailed. The core idea of the proposed strategy is to comprehensively consider the imbalance compensation and load rate balancing between the two areas to calculate the split-phase power and current reference values of each 3P4L converter and achieve the static error-free tracking of the reference values through the QPR current inner-loop control. These reference values are then tracked with zero steady-state error using QPR current inner-loop control. Finally, the effectiveness of the proposed control strategy is verified through a 3P4L M-LVDC case study conducted on the PSCAD/EMTDC software. The results indicate that the proposed method not only can reduce the three-phase imbalance degrees from >20% to <0.5%, but also achieve excellent balanced load rates, with the load-rate difference smaller than 1.5%.

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Keywords

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