Decomposition Problem in Process of Selective Identification and Localization of Voltage Fluctuations Sources in Power Grids
Piotr Kuwałek
TL;DR
This paper addresses the decomposition problem within a cascade-based approach for selective identification and localization of voltage fluctuation sources in power grids. It employs the enhanced empirical wavelet transform (EEWT) as the decomposition step following carrier demodulation to automatically segment the analyzed signal into components corresponding to distinct disturbance sources. Experimental results on a lab-scale low-voltage radial grid show that the method can correctly identify the number and approximate supply points of sources, but errors in estimating operating-state frequencies and localization arise from EEWT-induced spectral segmentation when component spectra mix. The authors discuss potential causes and suggest that alternative empirical decomposition methods or new basis functions tailored to amplitude-modulating signals may improve robustness for real-grid applications.
Abstract
Voltage fluctuations are common disturbances in power grids, therefore the effective and selective process of identification and localization of individual voltage fluctuations sources is necessary for the minimization of such disturbances. Selectivity in the process of identification and localization disturbing loads is possible by the use cascade of blocks: demodulation, decomposition and propagation assessment. The effectiveness of this approach is closely related to the used method of decomposition. The paper presents the problem of decomposition process for the selected method of selective identification and localization of voltage fluctuation sources, in which the algorithm of enhanced empirical wavelet transform (EEWT) is used as the decomposition method. The paper presents selected research results from the real power grid, for which the result of selected approach causes mistakes in the process of identification and localization of voltage fluctuations sources. The potential causes of such mistakes related to the decomposition process are discussed on the basis of obtained research results.