With the evolving concept of smart grids, Local Distribution Companies (LDCs) are gradually integrating advanced technologies and intelligent infrastructures to maximize distribution system capability, modernize the grid, and lay the foundation for smart loads. This book first presents a novel smart distribution system operation framework for smart charging of plug-in electric vehicles (PEVs). Thus, a three-phase Distribution Optimal Power Flow (DOPF) model is proposed, which incorporates comprehensive models of underground cables, transformers, voltage dependent loads, taps and switch capacitors, and their respective limits, to determine optimal feeder voltage-control settings and PEV smart-charging schedules. Various objective functions from the perspective of the LDC and customers are considered, and controlled tap, switch capacitors, and charging schemes are determined for various scenarios to address the shortcomings of uncontrolled charging, using two realistic feeder models to test and validate the proposed approach.