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Author: search.filters.author.Pothisarn, ChaichanSubject: search.filters.subject.Discrete wavelet transforms

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    Discriminating among inrush current, external fault and internalwinding fault using coefficient of DWT
    (2012-06-12)
    Jettanasen, Chaiyan
    ;
    Klomjit, Jittiphong
    ;
    Yodkhuang, Apichart
    ;
    Ngaopitakkul, Atthapol
    ;
    Pothisarn, Chaichan
    This paper proposes a technique for discriminating among inrush current, external fault and internal winding fault of three-phase two-winding transformer which variations of coefficients of high frequency component obtained from DWT of differential current are analyzed. The maximum coefficient details of DWT are performed as comparison indicator. Various cases based on Thailand electricity transmission and distribution systems are studied to verify the validity of the proposed algorithm. Results show that the proposed technique has good accuracy in the considered system.
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    Behaviour of internal fault and external fault in power transformer using discrete wavelet transform
    (2012-06-12)
    Ngaopitakkul, Atthapol
    ;
    Pothisarn, Chaichan
    The differential protection is aimed at detecting internal faults in transformer windings. Therefore, it is necessary to understand fault behaviour before doing performing decision algorithm. This paper presents behaviour of internal winding fault and external short circuit in a three-phase two-winding transformer. The advantage of the discrete wavelet transform (DWT) is considered herein. The fault is simulated using ATP/EMTP and the behaviour analysis of signals is performed using DWT. The variation of high frequency components of differential current signals is presented in this paper. The results obtained from the analysis will be useful in the development of a fault detecting scheme for power transformer in the future.
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    Behavior of winding to ground fault in transformer windings using discrete wavelet transform
    (2010-12-01)
    Pothisarn, Chaichan
    ;
    Ngaopitakkul, Atthapol
    ;
    Pongchaisrikul, Worravut
    ;
    Apisit, Chaowat
    ;
    Jonpermpoonpol, Saridroje
    In the literature for fault detection, most of research works have never been mentioned about the high frequency transformer including capacitances. This paper presents behaviour of winding to ground fault signals in a three-phase two-winding transformer. The advantage of the discrete wavelet transform (DWT) is that the band of analysis can be fine adjusted so that high frequency components and low frequency components are detected precisely, consequently DWT is considered herein. The fault is simulated using ATP/EMTP and the behaviour analysis of signals is performed using DWT. The variation of high frequency components of differential current signals is proposed in this paper. The results obtained from the analysis will be useful in the development of a detect fault scheme for power transformer in the future.