The invention relates to a method for analysing the quality of the electrical energy in a three-phase electric network, characterised in that it comprises the steps of: Measuring (El) a set of magnitudes comprising one electrical magnitude per phase, Forming (E2) a space vector from an instantaneous three-dimensional transformation of the set of measured electrical magnitudes, Determining (E3) a set comprising at least one parameter representative of the quality of the electrical energy in the three-phase electric network, depending on the space vector.
