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Author: search.filters.author.Ngaopitakkul, AtthapolSubject: search.filters.subject.Fuzzy logic

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    Discrete wavelet transform and fuzzy logic algorithm for classification of fault type in underground cable
    (2018-01-01)
    Yoomak, Suntiti
    ;
    Pothisarn, Chaichan
    ;
    Jettanasen, Chaiyan
    ;
    Ngaopitakkul, Atthapol
    This paper proposes the combination of discrete wavelet transform (DWT) and fuzzy logic to classify the fault type in underground distribution cable. The DWT is employed to decompose high frequency component from fault signal with the mother wavelet daubechies4 (db4). The maximum coefficients detail of DWT from phase A, B, C and zero sequence for post-fault current waveforms are considered as an input pattern of decision algorithm. Triangle-shaped S-shaped and Z-shaped membership function with maximum, medium, minimum, and zero are used to create a function for the input variable. Output variable of fuzzy are designated as values range 1 to 10 which corresponding with type of fault. The obtained average accuracy results shown that the proposed decision algorithm is able to classify the fault type with satisfactory accuracy.
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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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    The combination of discrete wavelet transform and fuzzy logic algorithm for fault classification on transmission system
    (2012-10-01)
    Ngaopitakkul, Atthapol
    In the literature for fault classification, several decision algorithms have different solutions and techniques. The most research works have only considered the fault diagnosis for single bus systems and two-bus systems. In fact, transmission lines are connected to each other and become a large grid connected system. During faults, it is necessary for the protection system to deal with a complicated transmission network. This paper proposes a new technique using discrete wavelet transform (DWT) and Fuzzy Logic in order to identify the fault types on transmission systems. The DWT is used to detect the high frequency components from these signals. Positive sequence current signals are used in fault detection decision algorithm. The variations of first scale high frequency component that detects fault are used as an input for the fuzzy logic. Various cases studies based on Thailand electricity transmission systems have been investigated so that the algorithm can be implemented. Fuzzy logic is also compared with the comparison of the coefficients DWT technique. The proposed method gives satisfactory accuracy, and will be very useful in the development of a modern protection scheme for electrical power transmission systems. ICIC International © 2012.