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Author: search.filters.author.Apisit, ChaowatSubject: search.filters.subject.Simultaneous fault

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    Algorithm improvement to predict fault location of simultaneous fault in underground cable
    (2013-11-11)
    Apisit, Chaowat
    ;
    Ngaopitakkul, Atthapol
    In the literature for fault location, most of research works have never been mentioned about effects of simultaneous faults. This paper presents a new decision algorithm that will be developed in order to predict precisely fault location, during simultaneous fault, in an underground distribution system using discrete wavelet transform (DWT). The advantage of the 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 signal is simulated using ATP/EMTP. The DWT is used to detect the high frequency components. Coefficients of positive sequence current signals are calculated. The positive sequence current as extracted to several scales with the DWT, and the coefficients of the first scale from the DWT are investigated. The time that the fault signal uses to reach the ends of the distribution line is considered, then, applied so that the distance of fault can be calculated. Various case studies have been carried out including the single fault and simultaneous fault. The result is found that the proposed algorithm gives satisfactory both in case of single fault and simultaneous fault. © 2013 The Institute of Electrical Engineers of Japan.
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    Identifying types of simultaneous fault in transmission line using discrete wavelet transform and fuzzy logic algorithm
    (2013-07-17)
    Ngaopitakkul, Atthapol
    ;
    Apisit, Chaowat
    ;
    Bunjongjit, Sulee
    ;
    Pothisarn, Chaichan
    In the literature for fault classification, several decision algorithms have different solutions and techniques. These research works have been rarely mentioned about simultaneous faults in transmission systems. This paper presents the decision algorithm for identifying types of simultaneous fault along the transmission line. Decision algorithms based on discrete wavelet transform (DWT) and fuzzy logic are investigated. The analysis of fault signals is performed using DWT. The DWT is used in order to detect the high frequency components. The coefficient details (phase A, B, C and zero sequence of post-fault current signals) of DWT at the first peak time that positive sequence current can detect fault, are performed as an input for the fuzzy logic. The result shows that the accuracy of the proposed algorithm is highly satisfactory. © 2013 ICIC International.
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    Study of characteristics for simultaneous faults in electrical power systems based on wavelet transform
    (2010-12-01)
    Ngaopitakkul, Atthapol
    ;
    Apisit, Chaowat
    In the literature for fault detection, most of research works have never been mentioned about effects of simultaneous faults. This paper presents behaviour of characteristics for simultaneous fault signals in a 500-kV electrical power transmission system using wavelet transform. The fault signal is simulated using PSCAD/EMTDC and the behavior analysis of signals is performed using discrete wavelet transform (DWT). The DWT is used in order to detect the high frequency components. The results obtained from the analysis will be useful in the development of a detect fault scheme for electrical transmission line in the future due to an effect of the other fault that occurs at the other side of the system (bus NCO) leading to the malfunction of the protective relays.