Defining and measuring synchrophasors based on symmetry principles

We proposed a new type PMU by combining spiral vector theory with group theory. First, a synchrophasor is defined as a rotation vector that had three elements that are AC frequency, the magnitude and the phase angle, then AC frequency and the magnitude is estimated using gauge differential voltage group, next the phase angle of the synchrophasor is estimated using two symmetric synchrophasor groups, next space synchrophasor is defined, last a field test example is presented. We discovered analytic synchrophasor solutions for pure sinusoids.