Wide area measurement system (WAMS) based software solutions are getting integrated into the energy management system (EMS) of the smart grid. Angle difference monitoring is one of the most important use cases as far as WAMS base control room applications are concerned. The real-Time angular separation between the nodes provides information related to the stress of transmission corridor. To monitor angle differences across the power system a reference angle must be selected in the control room software solution. This article revisits the concept of reference angle selection techniques for wide area control room operation. Concepts of individual bus angle, a center of inertia angle and center of power angle-based reference angle selection techniques are explored and the most suitable technique for real-Time reference angle selection is suggested. © 2022 IEEE.