Method and apparatus for real time measurement of three phase electrical parameters

The present invention is directed to real time measurement of balanced or unbalanced three phase electrical parameters such as power, voltage, current and frequency. Specifically, the invention is directed to real time measurement of balanced or unbalanced three phase electrical parameters of electrical power generators using a phase-locked quadrature detector. An apparatus and method for determining, in real time, the key parameters of a three phase system electrical generator's output. A pair of reference vectors in quadrature (orthogonal) is phase-locked to a selected input open delta line to line voltage vector. Preferably, the cosine reference vector is locked 45° out of phase from the selected input vector whereby a best projection of the input vector onto the quadrature pair is provided and increases accuracy in subsequent magnitude and phase calculations. The phase-locked reference vectors provide a basis for computing the magnitude and phase angle for the remaining open delta line to line voltage vectors and three line to neutral current vectors. Instantaneous measurement of magnitude and phase angle for the three line to line voltages and three line to neutral currents, the generator's real power (watts), volt-amperes reactive (VARS), apparent power (VA), power factor (PF) and, as a result of the phase locking, the precise frequency of the generator are possible.