Ngaopitakkul, Atthapol

Preferred name

Alternative Name

Ngaopitakkul, A.

Main Affiliation

School of Engineering

atthapol.ng@kmitl.ac.th

Now showing 1 - 10 of 126

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Switching angle design for pulse width modulation AC voltage controller using genetic algorithm and distributed artificial neural network
(2011-07-26)
Jitta, Pattaraporn
;
Kaitwanidvilai, Somyot
;
Ngaopitakkul, Atthapol
This paper proposes a technique to design the switching angles in a PWM AC voltage controller using genetic algorithms (GA) and distributed artificial neural network (ANN). In the proposed technique, GA is used to evaluate the turn on and turn off angles of PWM pattern to reduce the low order harmonic content in PWM output voltage. The results from GA are then used to train the distributed ANN. The advantages gained from the proposed technique are the reduction of complexity of training process and the improvement of the ability of the ANN. In addition, the total harmonic distortion of voltage, which calculated from the low order harmonic content, is adopted in the proposed fitness function. Thus, the load value is not necessary to be known before stating the proposed technique. Simulation results show that the proposed technique is superior to the conventional fixed-duration pulse technique.
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A new directional relay algorithm for the protection of transmission network systems using discrete wavelet transforms
(2010-12-01)
Ngaopitakkul, A.
;
Kaitwanidvilai, S.
This paper proposes a novel directional relay algorithm to protect transmission network systems with an application of discrete wavelet transform (DWT). The fault signals are simulated using PSCAD/EMTDC. The coefficients of the positive sequence current obtained from each bus are compared in order to identify the direction of fault signals. The coefficient ratio between buses that the fault occurred is calculated so that the proper protective relay sequence can be selected. The result is shown that the algorithm is capable of performing the fault detection as well as arranging the protective relay sequence, with accurate results. ©2010 IEEE.
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Coefficient comparison technique of discrete wavelet transform for discriminating between external short circuit and internal winding fault in power transformer
(2012-01-01)
Pothisarn, C.
;
Jettanasen, C.
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Klomjit, J.
;
Ngaopitakkul, A.
This paper proposes a technique for detecting and identifying 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 in order to discriminate between internal fault and external short circuit. 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 to detect fault and to identify its position in the considered system.
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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.
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Lightning location on 115-kV transmission line using travelling waves
(2018-11-01)
Bunjongjit, Sulee
;
Ngaopitakkul, Atthapol
;
Leelajindakrairerk, Monthon
A lightning strike can be very severe to the transmission system with high impulse current that can damage equipment and cause the operation of the system to be halted. However, currently used lightning location methodology that does not provide the desired accuracy. So, this paper proposed the lightning location methodology on the transmission line based on discrete wavelet transform (DWT) and travelling wave theory. The Alternative Transients Program/Electromagnetic Transients Program (ATP/EMTP) software has been used to simulate the transmission system using in this research. The comparative study between proposed and currently used has been done in order to evaluate the performance in term of accuracy to detect the lightning location on the transmission line. The result has shown that the proposed methodology can be achieved desire accuracy and can be further implemented in actual transmission line protection system in the future.
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Characteristics and effects of conducted emission from grid-connected and stand-alone micro-inverters in a nano-grid road lighting system
(2019-10-01)
Jettanasen, Chaiyan
;
Ngaopitakkul, Atthapol
A road lighting system is important for drivers and uses a lot of energy. The road lighting system must be installed throughout roads which have a long distance and a large volume, which causes power loss in the power transmission line. The concept of combining a power generation system by using a solar power system and a road lighting system is presented to solve this problem; it is called "a nano-grid road lighting system". The nano-grid system consists of a grid-connected system and a stand-alone system and both systems use micro-inverters to convert the electric power for LED luminaire loads. Both micro-inverters are comprised of switching devices that cause the conducted emission (CE) in the electrical system. The LED luminaire is a very sensitive load because it is less resistant to the CE. Therefore, this research studies the CE in the nano-grid system in each period according to the working pattern of the device to study the CE characteristics for use in the design of CE attenuation methods in the future. The CE of the stand-alone system which is used at nighttime gives a higher level than the grid-connected system and exceeds the Comité International Spécial des Perturbations Radioélectriques (CISPR) 14-1 standard. The CE of the grid-connected system has a high level in the early frequency ranges, whereas the CE of the stand-alone system has a high level throughout the test frequency range.
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Study of harmonics issued from electronic ballast used to reduce energy consumption in Thailand's building
(2014-01-01)
Jettanasen, C.
;
Ngaopitakkul, A.
In 2009, the T5 fluorescent tube lamp with electronic ballast was launched by the Electricity Generating Authority of Thailand (EGAT) in order to reduce energy consumption in building. The ballast is one of major components of fluorescent lamp. The installation of T5 fluorescent lamp in building has the effect of harmonics. This paper investigated the impact of harmonics from various electronic ballasts existing commercially, and compared with conventional ballast. The obtained results show that the T5 fluorescent tube lamp functioning with electronic ballast is a promising candidate to replace the T8 fluorescent tube lamp with electromagnetic and low watt loss ballast in building. © 2014 IEEE.
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Discrete wavelet transform for improving the accuracy of an unbalance current protection relay due to transient fault and inrush current signals
(2019-05-01)
Patcharoen, Theerasak
;
Ngaopitakkul, Atthapol
An unbalance current protection relay (60C, 51NC) cannot operate fast enough to avoid catastrophic failure against high system fault currents within capacitor units because traditional unbalance current protection relays are not capable of distinguishing and classifying transient fault current and switching inrush current. This paper proposes a new algorithm for the detection and classification of such current signals. The program used for the simulation was PSCAD/EMTDC. The current signals output was used as discrete wavelet transform (DWT) input. The wavelet-based fault and inrush current detection and classification unit received the various captured transient current signals, and used DWT to detect and analyse various cases studies. The actual inrush current signals from both the experimental setup and testing on an actual 115 kV HV shunt capacitor bank were used to verify the proposed algorithm. Results show that the proposed algorithm is effective at accurately identifying fault and inrush currents.
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Discrete wavelet transform and probabilistic neural network algorithm for classification of fault type in underground cable
(2012-01-01)
Ngaopitakkul, A.
;
Suttisinthong, N.
This paper proposes an algorithm based on a combination of discrete wavelet transform (DWT) and probabilistic neural network (PNN) for classifying fault types on underground cable. Simulations and the training process for the PNN are performed using ATPIEMTP and MATLAB. The mother wavelet daubechies4 (db4) is employed to decompose high frequency component from these signals. The maximum coefficients of DWT of phase A, B, C and zero sequence for post-fault current waveforms 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 coefficients of DWT are also compared with those of PNN in this paper. The results show that the proposed algorithm is capable of performing the fault classification with satisfactory accuracy. © 2012 IEEE.
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A novel discrete wavelet transform based on traveling wave technique for identifying the fault location for transmission network systems
(2013-01-01)
Patcharoen, Theerasak
;
Ngaopitakkul, Atthapol
This paper proposes a technique to identify fault location on transmission systems using discrete wavelet transforms (DWTs). Fault conditions are simulated using alternative transients program/electromagnetic transients program (ATP/EMTP) in order to obtain the current signals. Various cases based on Thailand electricity transmission systems are studied to verify the validity of the proposed technique. The comparisons among the maximum coefficients in first scale of all buses that can detect fault are performed to detect the faulty bus. The first peak time of positive sequence current obtained from the faulty bus is used as input data for the traveling wave equation. It is shown that the proposed technique gives satisfactory accuracy and is suitable for all types of fault occurring in different sections of transmission lines. © 2013 Institute of Electrical Engineers of Japan.

Ngaopitakkul, Atthapol

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