PDF(3153 KB)
Voltage Unbalance Compensation Control Strategy for Active Distribution Networks Based on Adaptive Virtual Impedance
LIU Bin, TAN Zhukui, TANG Saiqiu, ZHAO Shuai, CHEN Yushi, ZHANG Qian, LU Xiaoqing
Electric Power Construction ›› 2025, Vol. 46 ›› Issue (11) : 1-9.
PDF(3153 KB)
PDF(3153 KB)
Voltage Unbalance Compensation Control Strategy for Active Distribution Networks Based on Adaptive Virtual Impedance
[Objective] To address the problem of voltage quality deterioration caused by line impedance differences and load current imbalances in the microgrid and improve the coordinated operation capability of distributed energy resources （DERs）， a secondary compensation control strategy based on adaptive virtual impedance is proposed to solve the problem of improving the voltage quality of the microgrid under load current imbalance.[Methods] The scheme comprised three parts： a local DER controller， microgrid control unit， and microgrid group control center. The microgrid control unit adjusted the power exchange according to the set value issued by the group control center and adjusted the voltage at the point of common coupling through the secondary control signal. At the DER level， the V-I droop control strategy was adopted to achieve fast voltage and frequency stability. The output of the droop controller was combined with the secondary control signal and correction voltage to effectively eliminate the influence of the line impedance on the current sharing accuracy.[Results] A real-time simulation based on MATLAB/Simulink on the OPAL-RT simulator showed that the voltage imbalance reduced to less than 1%， and the current sharing accuracy significantly improved compared with the traditional droop control method.[Conclusions] The hierarchical control strategy proposed in this study effectively solved the problem of voltage quality degradation caused by line impedance differences and load imbalances under the condition of real-time communication between DERs through the synergy of virtual impedance compensation and secondary voltage correction. Furthermore， it realized current sharing control under unbalanced load conditions， providing a new solution for the coordinated control of multiple microgrids in an active distribution network environment.
distributed energy resources / active distribution network / adaptive virtual impedance / voltage imbalance / secondary compensation control
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