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    Item type:Publication,
    Identification of fault location for simultaneous fault in distribution system using discrete wavelet transform
    (2011-04-01)
    Pothisarn, C.
    ;
    Jettanasen, C.
    ;
    Ngaopitakkul, A.
    ;
    Apisit, C.
    Currently, the most effective technique for identifying fault location, based on a travelling wave, has been proposed in several research papers. However, the effects of simultaneous faults have been neglected. In order to overcome this problem, a new algorithm will be developed in order to predict fault location precisely. This paper presents a technique to detect fault locations, during simultaneous fault, in an underground distribution system using discrete wavelet transform (DWT). The DWT is used to detect the high frequency components. 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. The result is found that the proposed algorithm gives satisfactory both in case of single fault and simultaneous fault. ICIC International © 2011.
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    Item type:Publication,
    Identification of simultaneous fault types in electrical power system using the comparisons technique of DWT coefficients
    (2011-04-01)
    Ngaopitakkul, A.
    ;
    Apisit, C.
    ;
    Jettanasen, C.
    ;
    Pothisarn, C.
    This paper is aimed to propose a novel distance relay algorithm, which includes the effect of simultaneous fault. The previous research paper can give an uncertain result in a fault classification during simultaneous faults. In order to overcome this problem, the comparison of coefficients of discrete wavelet transform (DWT) has been developed. The fault analysis is performed using PSCAD/EMTDC. The current waveforms obtained from PSCAD/EMTDC are extracted to several scales with the wavelet transform, and the coefficients of the first scale from the wavelet transform are investigated. The coefficient details of DWT at the first peak time that positive sequence current can detect fault, are performed as comparison indicator in order to classify fault types. It is found that the technique proposed in this paper gives satisfactory results in the simultaneous fault classification. © 2011 ISSN 2185-2766.