1540-7977/16©2016IEEE 46 IEEE power & energy magazine may/june 2016 T THE DEPLOYMENT OF A DISTRIBUTION SYSTEM operator (DSO) is becoming a necessity as a result of the dis- tribution grid’s increasing roles and functionalities to ensure an efficient and reliable delivery of electricity to emerg- ing proactive customers. The preferences of customers have evolved as they are willing to have more control over their energy use and transactions with the utility grid. In parallel, there is a potential need for an intermediate entity between the independent system operators (ISOs) or regional transmis- sion operators (RTOs) and distributed energy resource (DER) owners due to the limited visibility and control over the meter resources. A DSO may efficiently utilize DERs to improve system reliability and resiliency and reduce emissions and greenhouse gasses by resource diversification. DSO Functions A DSO may be considered as the evolution of a distribu- tion management system (DMS). Traditionally, a DMS is responsible for overall operation reliability, power deliv- ery quality, minimum energy losses, and the normal and FACES—IMAGE LICENSED BY INGRAM PUBLISHING, BACKGROUND—GRAPHIC STOCK Digital Object Identifier 10.1109/MPE.2016.2524960 Date of publication: 19 April 2016 The Interface of Power By Dimitra Apostolopoulou, Shay Bahramirad, and Amin Khodaei