Wavelet Transform and Time Frequency Atoms Based Approach to Power Quality Monitoring

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ABSTRACT (ECS-0140636)An accurate and efficient approach to power quality monitoring will be developed. A power disturbance is typically a non-stationary signal with magnitude variance and frequency deviation. The proposed work deals with constructing the complex Time Frequency Atom (TFA) for power quality monitoring, in which there is no coupling between the central frequency and frequency radius. The TFA based Wavelet Transform (WT) approach has the following advantages over that based on a complex Wavelet function: (1) Since the central frequency and frequency radius of each filtering channel can be set or tuned separately and flexibly, the separation of different filtering channels, which are designated for a fundamental component and harmonics, in the frequency plane can be achieved, i.e. eliminating the interference between each other. The concept of "Wavelet Energy Distribution"(WED) is proposed, which is based on a complex Wavelet function and WT, to fulfill the "spectrum scanning" by a non-uniform frequency window. Further, novel power quality indices will be created that use the TFA and WED. The approach will be evaluated by using simulated power disturbance waveforms, followed by an on-line evaluation in the laboratory and in industrial sites, based on hardware implementation. The accurate estimation of magnitudes and frequencies of fundamental as well as harmonic components is also essential to power system control and protection. Therefore, the project will promote research and teaching in not only the power quality field but also power system control, protection, and the development of power instruments/apparatus.