Calibration of a Virtual Instrument for Power Quality Monitoring

Abstract

The paper describes a virtual instrument for power quality monitoring based on NI LabVIEW™ platform and simultaneous measurements of electrical voltages and currents. The virtual power quality analyzer is realized by using National Instruments 9225 and 9227 modules for voltage and current measurements, respectively, NI cDAQ 9174, 4 slot USB chassis and a PC. The created virtual instrument measures power quality characteristics: power frequency, voltage variations, magnitude of rapid voltage changes, flicker severity, voltage unbalance, total harmonic distortion, as well as the elements of voltage dips, short interruptions, and long interruptions defined in the standard EN 50160 for voltage characteristics of supplied electricity. The measurement is according to the general guide on harmonics and interharmonics measurements IEC 61000-4-7. The calibration and verification of the power quality analyzer is a complex task and it is performed by using the laboratory calibrator FLUKE 5500A. The results of calibration and verification of the developed virtual instrument, as well as the results of power quality measurements near different lightning technologies are presented