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The Analysis of Lightning Strikes to MEA's Distribution Lines on Different Impact Positions
(2017-01-01)
Sestasombut, P.
;
Ngaopitakkul, A.
This paper focuses on behaviour of voltage across insulator when the lightning strikes on different impact positions of Metropolitan Electricity Authority (MEA) 24 kV distribution lines in Thailand. The simulations and analysis are performed using Alternative Transients Program/Electromagnetic Transients Program (ATP/EMTP) to investigate the voltage across insulator. The results indicate that when the lightning strikes to phase conductor or shielding failure occurs, the voltage across insulator where the terminal point is more than the middle point is about 1.5 times. This case, the ground resistance and grounding distance of overhead ground wire (OHGW) is not influential on the voltage across insulator. However, in case the lightning strikes to OHGW, the voltage across insulator where the terminal point is more than the middle point is about 1.2 times and the ground resistance as well as grounding distance of OHGW plays an important role for the voltage across insulator. The analysis shows that when the lightning strikes to the terminal line are considerably more severe than the middle line. Therefore, the lightning protection should be specially considered at the terminal point. The peak current magnitude and the front time lightning current waveform are essential parameters when observing the voltage across insulator. However, the tail time is not an important parameter with regard to the voltage across insulator.
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An experimental setup investigation to study characteristics of fault on transmission system
(2015-01-01)
Yindeesap, P.
;
Ngaopitakkul, A.
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Pothisarn, C.
;
Jettanasen, C.
This paper proposes the experimental setup for studying the characteristics of fault caused by balance and unbalance on a transmission system. The parameters of transmission system (inductance and capacitance) are calculated based on forms of transmission tower, size of conductor, types of conductor and arrangement of transmission line and, they normalized to obtain the values in the π- equivalent circuit model at voltage level of 400 V. In addition, the ATP/EMTP is used to compare the simulated results with the experimental setup in order to show the advantage of the experimental setup. The obtained results show that the similarity between the two waveforms. The experimental setup will be useful in the development of short-circuit protection system in laboratory.
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Application of DWT and fuzzy logic algorithm for classifying simultaneous fault types
(2011-12-01)
Pothisarn, C.
;
Ngaopitakkul, A.
This paper proposes a technique using discrete wavelet transform (DWT) and fuzzy logic for identifying types of simultaneous fault along the transmission systems. The PSCAD/EMTDC is used to simulate fault signals. The mother wavelet daubechies4 (db4) is employed to decompose high frequency component from these signals. The coefficients detail (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, is performed as input variables for the proposed algorithm. The result shows that the proposed technique gives satisfactory accuracy, and will be very useful in the development of a power system protection scheme. © 2011 IEEE.
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DWT and RBF neural networks algorithm for identifying the fault types in underground cable
(2011-12-01)
Ngaopitakkul, A.
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Pothisarn, C.
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Bunjongjit, S.
;
Suechoey, B.
A new technique for classifying fault type in underground distribution system has been proposed. Discrete wavelet transform (DWT) and Radial basis function (RBF) neural network are investigated. Simulations and the training process for the RBF neural network are performed using ATP/EMTP and MATLAB. The mother wavelet daubechies4 (db4) is employed to decompose high frequency component from these signals. Positive sequence current signals are used in fault detection decision algorithm. The output pattern of RBF is divided into two case studies training for comparison between classifying of the fault types and identifying the phase with fault appearance. The variations of first scale high frequency component that detect fault are used as an input for the training pattern. The comparison of the coefficients DWT is also compared with the RBF neural network in this paper. The result is shown that an average accuracy values obtained from RBF gives satisfactory results. © 2011 IEEE.
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Study of characteristics for simultaneous faults in distribution underground cable using DWT
(2011-12-01)
Ngaopitakkul, A.
;
Pothisarn, C.
;
Leelajindakrairerk, M.
In the literature for fault detection, most of research works have never been mentioned about effects of simultaneous faults. This paper presents behavior of characteristics for simultaneous fault signals in an electrical distribution underground cable using wavelet transform. The fault signal is simulated using ATP/EMTP, and the behavior analysis of signals is performed using discrete wavelet transform (DWT). The DWT is used 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 distribution underground cable in the future due to an effect of the other fault that occurs at the other side of the system; this leads to the malfunction of the protective relays. © 2011 IEEE.
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Discrete wavelet transform and back-propagation neural networks algorithm for fault classification in underground cable
(2011-07-26)
Kaitwanidvilai, S.
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Pothisarn, C.
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Jettanasen, C.
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Chiradeja, P.
;
Ngaopitakkul, A.
This paper proposes a new technique using discrete wavelet transform (DWT) and back-propagation neural network (BPNN) for fault classifications on underground cable. Simulations and the training process for the back-propagation neural network are performed using ATP/EMTP and MATLAB. The mother wavelet daubechies4 (db4) is employed to decompose high frequency component from these signals. Positive sequence current signals are used in fault detection decision algorithm. The variations of first scale high frequency component that detect fault are used as an input for the training pattern. Various cases studies based on Thailand electricity distribution underground systems have been investigated so that the algorithm can be implemented. The results are shown that an average accuracy values obtained from BPNN can indicate the fault classification with satisfactory accuracy, and will be very useful in the development of a power system protection scheme.
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Discrete wavelet transform for fault types in underground distribution system
(2010-12-13)
Ngaopitakkul, A.
;
Apisit, C.
In this paper, a technique for identifying the phase with fault appearance in underground cable is presented. The Wavelet transform has been employed to extract high frequency components superimposed on fault signals simulated using ATP/EMTP. The coefficients obtained from the Wavelet transform are used in constructing a decision algorithm. Various cases have been investigated so that the algorithm can be implemented. It is found that the proposed method can indicate the fault types with satisfactory accuracy. © 2010 American Institute of Physics.
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Coefficient comparison technique for identifying the fault types in underground cable
(2010-12-01)
Ngaopitakkul, A.
;
Kaitwanidvilai, S.
;
Apisit, C.
This paper proposes a novel comparison technique for identifying the phase with fault appearance in underground cable using Discrete Wavelet Transform. The Wavelet transform has been employed to extract high frequency components superimposed on fault signals simulated using ATP/EMTP. The fault type algorithm is constructed on the basis of coefficient comparison from signals decomposed from Discrete Wavelet Transform. Various cases studies based on Thailand electricity distribution underground systems have been investigated so that the algorithm can be implemented. It is found that the proposed method can indicate the fault types with satisfactory accuracy. ©2010 IEEE.
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Identification of fault locations in underground distribution system using Discrete Wavelet Transform
(2010-12-01)
Ngaopitakkul, A.
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Apisit, C.
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Pothisarn, C.
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Jettanasen, C.
;
Jaikhan, S.
In this paper, a technique for detecting faults in underground distribution system is presented. Discrete Wavelet Transform (DWT) based on traveling wave is employed in order to detect the high frequency components and to identify fault locations in the underground distribution system. The first peak time obtained from the faulty bus is employed for calculating the distance of fault from sending end. The validity of the proposed technique is tested with various fault inception angles, fault locations and faulty phases. The result is found that the proposed technique provides satisfactory result and will be very useful in the development of power systems protection scheme.
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Identification of fault types for underground cable using discrete Wavelet transform
(2010-12-01)
Apisit, C.
;
Ngaopitakkul, A.
In this paper, a technique for identifying the phase with fault appearance in underground cable is presented. The Wavelet transform has been employed to extract high frequency components superimposed on fault signals simulated using ATP/EMTP. The coefficients obtained from the Wavelet transform are used in constructing a decision algorithm. Various cases have been investigated so that the algorithm can be implemented. It is found that the proposed method can indicate the fault types with satisfactory accuracy.

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