Virtual Instrumentation for Power Quality Analysis in the Main Supplying Point at Entrance of an Industrial Consumer

The aim of this paper is to present a practical system based on virtual instrumentation for analysis of industrial consumer power quality. This analyzer is implemented using hardware components (voltage and current transducers for instantaneous values; USB data acquisition module; laptop) and software (LabVIEW graphical programming environment). The acquisition of three currents and three voltages allows the proposed system to calculate on line and off line several parameters that characterize the electric power quality. The waveforms of currents and voltages can be viewed individually or all at once. Also, can computes and analyze: the average of Fast Fourier Transform FFT spectrum of time signals, the value of the total harmonic distortion factor THD, the fundamental frequency, the components level with the rms values of the measured harmonics. The total powers (active, reactive, apparent) and by components values are calculated; total three-phase power factor is also calculated. The proposed system allows data acquisition and implicitly power quality monitoring in a user-defined time interval. The system was tested in the secondary of the power transformer of an industrial consumer in the field of repair and maintenance of railway equipment. The validation of the obtained results was done by direct comparison with the indications of a Fluke 435 three-phase power quality analyzer.