Main objective of this paper is to provide a practical tool for the analysis and study of power quality and deforming regime. The LabVIEW graphical programming environment is used for designing virtual instrument to achieve the main two objectives. First goal is synthesizing a distorted signal by adding a number of sinusoidal harmonics which composing it. An accurate voltage signal and the current one are synthesized. Each harmonic amplitude, frequency and phase can be changed by simulation, noting the effects on the shape and parameters of the distorted signal obtained. For each signal distortion voltage and current are calculated following parameters: components level of the harmonic number including 0 (DC), 1 (fundamental), 2 (second harmonic), n (nth harmonic), up to and including the highest harmonic; the detected fundamental frequency resulting from searching the frequency domain; (THD) total harmonic distortion up to and including the highest harmonic. They are also calculated: active power, reactive power, apparent power and distorted power, power factor, each by component and the total value. The second objective of virtual instrument is power harmonic analysis for the experimental instantaneous input data of three-phase power consumer. These values instantaneous currents and voltages are obtained by data acquisition and are found saved in a text-based measurement file (.txt). This virtual instrument can be used at the same time in power quality education and research.