Absolute phase in power system applications

Phase on a power system is typically defined as the relative positions of the current and voltage waveforms and is normally referenced to the "A" phase voltage. With technology now available instead of using the "A" phase as a reference "UTC time" can be used as a reference. This "UTC time" can be derived from the global positioning system (GPS) and has the advantage of being a universal reference due to its availability anywhere on earth. Using a universal reference for phase measurements provides "absolute phase". Using absolute phase one can calculate the phase shift throughout the power system. Variation of phase shift is a direct measurement of system stress and can, therefore, be used to analyze and control the grid.