High performance power quality monitoring system

Monitoring systems related to power quality were built in order to verify that a system or machine is functioning properly in accordance to standards. This paper aims to present a system that was developed on the CompactRIO controller from National Instruments. As a programming tool, LabVIEW software was used to elaborate the platform in order to monitor and to detect disturbances that can occur in any power system. Methods such as Fast Fourier transform (FFT) and the Wavelet transform were used to monitor harmonics on the system and to detect short time voltage variations. When a short duration voltage fluctuation or an exceeding in the harmonic limits is noticed, the implemented system records the event time for further analysis. The platform also records all the signal in the time domain continuously without any blank window. The post-processing is performed using the samples of the recorded signal. The analyzer can choose the amount of pre- and/or post event time, in 60 Hz cycles, to rebuild the event waveform. To validate the platform, it was subjected to tests such as the system voltage variation, momentary interruption, voltage sag and violations in harmonic distortion rates.