Research on Three-Phase Unbalance Control Method for Low-Voltage Distribution Network Considering Constraint on Phase-Switching Times

To address the three-phase load unbalance caused by uneven phase allocation of single-phase users in low-voltage distribution networks, a load reconfiguration method considering the constraint on phase-switching times is proposed. The method takes the reduction of three-phase load unbalance degree as the main objective, sets an upper limit on phase-switching times in the model, and combines an approximate voltage-drop model of low-voltage radial feeders to compare the load distribution, voltage level and line loss before and after reconfiguration. The case results show that the unbalance degree of the 9-user case decreases from 61.29% to 4.55%; in the 30-user case, the unbalance degree decreases from 43.65% to 2.45%, and the line loss decreases from 8.36 kW to 8.04 kW. The results indicate that the proposed method can improve three-phase load distribution with fewer phase-switching operations.