Editing Phasor (section)

===Power engineering===
In analysis of [[three phase]] AC power systems, usually a set of phasors is defined as the three complex [[cube roots of unity]], graphically represented as unit magnitudes at angles of 0, 120 and 240 degrees. By treating polyphase AC circuit quantities as phasors, balanced circuits can be simplified and unbalanced circuits can be treated as an algebraic combination of [[symmetrical components]]. This approach greatly simplifies the work required in electrical calculations of voltage drop, power flow, and short-circuit currents. In the context of power systems analysis, the phase angle is often given in [[Degree (angle)|degree]]s, and the magnitude in [[Root Mean Square|RMS]] value rather than the peak amplitude of the sinusoid.

The technique of [[synchrophasor]]s uses digital instruments to measure the phasors representing transmission system voltages at widespread points in a transmission network.  Differences among the phasors indicate power flow and system stability.