Patent ID: 8766620

Claim:
A phase identification system, comprising: a power distribution station including a phase distortion device to generate voltage distortions of a known harmonic frequency in at least one of three phase voltage signals of the power distribution station; and a phase detection device configured to receive at least one of distorted three phase voltage signals and to identify a phase of the received voltage signal, the phase detection device comprising: a delay circuit for generating a phase shifted voltage signal of the received voltage signal; a transformation module for transforming the received voltage signal and the phase shifted voltage signal into d-q domain voltage signals of a known harmonic frequency reference frame; an amplitude calculation module for calculating an amplitude of a harmonic of the known harmonic frequency in the received voltage based on the d-q domain voltage signals; and a phase determination module for determining the phase of the received voltage signal by comparing the amplitude of the harmonic of the known harmonic frequency in the received voltage signal with a threshold value.