Multi-machine Collaboration and Optimization of Hybrid Distribution Transformers in Unbalanced Active Distribution Networks

Distributed photovoltaic access to the distribution network will exacerbate the system three-phase imbalance and irrational reactive power distribution. For this reason, this paper accesses hybrid distribution transformers (HDTs) at each key node of the distribution network, utilizes the high controllability of HDTs, and realizes an unbalanced distribution network power allocation scheme based on HDT multi-machine cooperative regulation. The scheme is characterized by considering three-phase coupling, establishing an optimization model with the objectives of minimizing network loss, voltage offset and overrun, three-phase unbalance and grid unbalance, and completing the online solution with an improved particle swarm-sticky bacteria algorithm. The simulation shows that the proposed novel power optimization allocation scheme can effectively reduce the overall network loss and three-phase unbalance degree of the distribution network and improve the overall balance of the distribution network under three-phase unbalance and voltage overrun.