Multi-resolution wavelet analysis for noise reduction in impulse puncture voltage measurements

摘要

This work describes an approach for digital processing of voltage impulse signals in puncture tests of insulators on high voltage laboratories, using wavelet transform based multi-resolution analysis. Quantifying the amplitude of such impulses is not a trivial task because they have typical magnitudes of hundreds of kilovolts and rise times of 100 ns to 200 ns. The processing is mainly necessary due to high frequency electromagnetic interferences caused by the impulse generation system, which may strongly affect the measurement accuracy and, consequently, the test result. This manuscript presents qualitative and quantitative results for different types of wavelets studied, as well as the best performance obtained by the filter. Software for signal processing and analysis was also developed for this application. Results are also presented using the wavelet filter for a pioneering inter-laboratory comparison between high voltage measuring systems used in impulse puncture tests of insulators. (C) 2019 Elsevier Ltd. All rights reserved.