TY  - EJOU
AU  - Dai, Qiji 
AU  - Li, Jikai 
AU  - Ning, Bohui 
AU  - Xu, Yutao 
AU  - Liu, Chang 
AU  - Zhang, Xuan 

TI  - Load Balancing Control Strategy for Multi-Substation Flexible Interconnection Distribution Networks Considering Unbalanced Power Compensation
T2  - Energy Engineering

PY  - 2025
VL  - 122
IS  - 10
SN  - 1546-0118

AB  - 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%.
KW  - Three-phase four-bridge-arm; Quasi-PR; direct current control; unbalanced power compensation

DO  - 10.32604/ee.2025.067304