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Author: search.filters.author.Klomjit, JittiphongSubject: search.filters.subject.Discrete Wavelet Transform

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    Comparison of mother wavelet for classification fault on hybrid transmission line systems
    (2017-07-01)
    Klomjit, Jittiphong
    ;
    Ngaopitakkul, Atthapol
    ;
    Sreewirote, Bancha
    This paper proposes comparison mother wavelets for fault classification on hybrid transmission line systems. Hybrid system consists of overhead line and underground cable of 115 kV. ATP/EMTP software has been used for generating fault signals. Then it varies location of fault, fault type and angle. Current signals and zero sequence are analyzed by Discrete Wavelet Transform (DWT) in MATLAB software. DWT decomposes high frequency components from fault signals. Coefficient in scale 1 has been decomposed from Mother Wavelets such as Daubechies (db), Symlets (sym), Biorthogonal (bior) and Coiflets (coif). The coefficient for any mother wavelet has same behavior but different value. Design algorithm for fault classification and compare the result. Therefore, comparison of mother wavelet for fault classification is important to provide the high accuracy. Daubechies (db) can give accuracy more than any mother wavelet.
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    Behaviour of interturn fault in power transformer winding using high frequency components of discrete wavelet transform
    (2012-12-01)
    Klomjit, Jittiphong
    ;
    Ngaopitakkul, Atthapol
    Behaviour of interturn winding fault signals in a three-phase two-winding transformer with delta connected primary and wye connected secondary, using high frequency components of DWT is proposed in this paper. The mother wavelet daubechies4 (db4) is employed to decompose high frequency components from signals. Various case studies have been done including the variation of fault inception angles, fault types, and fault locations. The result will be useful in the development of a fault detecting scheme for power transformer in the future. © 2012 IEEJ Industry Appl Soc.
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    Discriminating among inrush current, external fault and internal fault in power transformer using low frequency components comparison of DWT
    (2012-12-01)
    Jettanasen, Chaiyan
    ;
    Pothisarn, Chaichan
    ;
    Klomjit, Jittiphong
    ;
    Ngaopitakkul, Atthapol
    A technique using discrete wavelet transform (DWT) in order to discriminate among inrush current, internal fault, and external fault has been proposed. Daubechies4 (db4) is employed as mother wavelet in order to decompose low frequency components from fault signals. A ratio between per unit differential current and per unit time is calculated and performed as comparison indicator. The results obtained from the proposed technique have good accuracy to discriminating fault in the considered system. © 2012 IEEJ Industry Appl Soc.