Neutral current reduction control for smart transformer under the imbalanced load in distribution system

Abstract

Imbalanced loads arouse neutral current looping in the distribution system, which increases power loss and results in neutral potential variation. Compared to the conventional power transformer, the smart transformer (ST) has advantages on the downstream voltage regulation. Thus, this paper proposes a voltage control strategy based on ST to reduce the LV grid neutral current according with EN 50160 imbalanced voltage standard. The proposed control has been validated in the Matlab/Simulink, and the system performance under the proposed control has been simulated under the imbalanced loading profile in a 400 kVA, 10 kV/400 V distribution network. The results prove the proposed control can practically reduce the neutral current.