Electric Power Quality Monitoring (PQM) using Virtual Instrumentation

The paper presents a low-cost Virtual Instrument (VI) for monitoring the Power Quality (PQ) events. There are number of mathematical and machine intelligence techniques being used for analyzing the distorted, non-stationary current/voltage waveforms. Here in this paper a technique is used that visualizes the effect of various types of windows on non-stationary signals, and the primary focus is on finding the various harmonic components present. Fundamental frequency is estimated using Buneman Frequency Estimator and harmonic spectrogram is plotted using Short time Fourier Transform (STFT). The Dolph-Chebyshev window´s performance is found good and comparison is made. The zero padding technique is also implemented for the better detection of interharmonics. The system is developed on LabVIEW platform and the testing is done through simulation and live current/voltage input through data acquisition board.