In this article, model predictive based centralized control strategy is proposed to manage voltage variations and line congestions in smart transformer (ST) fed distribution networks with electric vehicles (EVs) and photovoltaic (PV) generators. ST is a power electronics-based transformer that exhibits intelligent features in control and communication fields. The proposed control scheme deals in coordinating the fast power electronics interfaced devices, such as EVs, ST and PVs in the low voltage (LV) side to maintain voltages as well as line congestions. The ST provides the voltage control in the LV side by setting the voltage reference at the source of the feeder in a similar manner a conventional transformer with on-load tap changers. Simulations are performed in a 38-bus distribution network to validate the efficacy of the proposed approach.