Ngaopitakkul, Atthapol
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Preferred name
Ngaopitakkul, Atthapol
Alternative Name
Ngaopitakkul, A.
Main Affiliation
Email
atthapol.ng@kmitl.ac.th
14 results
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Item type:Publication, Comparison of artificial intelligence methods for fault classification of the 115-kv hybrid transmission system(2020-06-01) ;Klomjit, JittiphongThis research proposes a comparison study on different artificial intelligence (AI) methods for classifying faults in hybrid transmission line systems. The 115-kV hybrid transmission line in the Provincial Electricity Authority (PEA-Thailand) system, which is a single circuit single conductor transmission line, is studied. Fault signals in the transmission line were generated by the EMTP/ATPDraw software. Various factors such as fault location, type, and angle were considered. Then, fault signals were analyzed by coefficient details on the first scale of the discrete wavelet transform. Daubechies mother wavelet from MATLAB software was used to decompose the fault signal. The coefficient value of the mother wavelet behaved depending on the position, inception of fault angle, and fault type. AI methods including probabilistic neural networks (PNNs), back-propagation neural networks (BPNNs), and support vector machine (SVM) were used to identify faults. AI input used the maximum first peak coefficients of phase ABC and zero sequence. The results obtained from the study were found to be satisfactory with all AI methodologies having an average accuracy of more than 98% in the case study. However, the SVM technique can provide more accurate results than the PNN and BPNN techniques with less computation burden. Thus, it is suitable for being applied to actual protection systems. - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Development and Analysis of a Fast-Charge EV-Charging Station Model for Power Quality Assessment in Distribution Systems(2025-09-01) ;Chiradeja, Pathomthat; ;Srisuksai, Panu ;Klomjit, JittiphongWith the rapid rise in electric vehicle (EV) adoption, the deployment of EV charging infrastructure—particularly fast-charging stations—has expanded significantly to meet growing energy demands. While fast charging offers the advantage of reduced charging time and improved user convenience, it imposes considerable stress on existing power distribution systems due to its high power and current requirements. This study investigated the impact of EV fast charging on power quality within Thailand’s distribution network, emphasizing compliance with accepted standards such as IEEE Std 519-2014. We developed a control-oriented EV-charging station model in power systems computer-aided design and electromagnetic transients, including DC (PSCAD/EMTDC), which integrates grid-side vector control with DC fast-charging (CC/CV) behavior. Active/reactive power setpoints were mapped onto (Formula presented.) current references via Park’s transformation and regulated by proportional integral (PI) controllers with sinusoidal pulse-width modulation (SPWM) to command the voltage source converter (VSC) switches. The model enabled dynamic studies across battery state-of-charge and staggered charging schedules while monitoring voltage, current, and total harmonic distortion (THD) at both transformer sides, charger AC terminals, and DC adapters. Across all scenarios, the developed control achieved grid-current THDi of <5% and voltage THD of <1.5%, thereby meeting IEEE 519-2014 limits. These quantitative results show that the proposed, implementation-ready approach maintains acceptable power quality under diverse fast-charging patterns and provides actionable guidance for planning and scaling EV fast-charging infrastructure in Thailand’s urban networks. - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Analysis of Investment Feasibility for EV Charging Stations in Residential Buildings(2025-09-01) ;Chiradeja, Pathomthat; ;Sottiyaphai, Chayanut; Klomjit, JittiphongThis study investigates the financial and operational feasibility of deploying electric vehicle (EV) charging infrastructure within high-density residential buildings, utilizing empirical operational data combined with comprehensive financial modeling. A 14-day monitoring period conducted at a residential complex comprising 958 units revealed distinct charging behaviors, with demand peaking during weekday evenings between 19:00 and 22:00 and displaying more dispersed yet lower overall utilization during weekends. Energy efficiency emerged as a significant operational constraint, as standby power consumption contributed substantially to total energy losses. Specifically, while total energy consumption reached 248.342 kW, only 138.24 kW were directly delivered to users, underscoring the necessity for energy-efficient hardware and intelligent load management systems to minimize idle consumption. The financial analysis identified pricing as the most critical determinant of project viability. Under current cost structures, financial break-even was attainable only at a profit margin of 0.2286 USD (8 THB) per kWh, while lower margins resulted in persistent financial deficits. Sensitivity analysis further demonstrated the considerable vulnerability of the project’s financial performance to small fluctuations in profit share and utilization rate. A 10% reduction in either parameter entirely eliminated the project’s ability to reach payback, while variations in energy costs, capital expenditures (CAPEX), and operational expenditures (OPEX) exerted comparatively limited influence. These findings emphasize the importance of precise demand forecasting, adaptive pricing strategies, and proactive government intervention to mitigate financial risks associated with residential EV charging deployment. Policy measures such as capital subsidies, technical regulations, and transparent pricing frameworks are essential to incentivize private sector investment and support sustainable expansion of EV infrastructure in residential sectors. - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Discriminating among inrush current, external short circuit and internal winding fault in power transformer using coefficient of DWT(2012-01-01) ;Klomjit, JittiphongThis paper proposes a technique for discriminating among inrush current, external fault and 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. 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 in the considered system - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Fault classification on the hybrid transmission line system between overhead line and underground cable(2017-08-30) ;Klomjit, JittiphongThis paper illustrates fault classification on hybrid transmission line. Current signals were analyzed by coefficients of discrete wavelet transform (DWT). Daubechies4 (db4) is employed as mother wavelet to decompose high frequency components from fault signals. In this paper, ATP/EMTP is used to simulate fault signal from current signals. Hybrid system between overhead line and underground cable of 115 kV from Provincial Electricity Authority (PEA-Thailand) system in case single circuit single conductor with overhead and underground was used as simulation case study. Various factors such as location of fault, fault type and fault angle have been taken into consideration. DWT is then applied on phase current and zero sequence signals using MATLAB software in order to obtain coefficient in scale 1 for further analysis. This value is mainly used to design algorithm for fault classification. Result obtained from the study is satisfactory. - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Comparison of mother wavelet for classification fault on hybrid transmission line systems(2017-07-01) ;Klomjit, Jittiphong; Sreewirote, BanchaThis paper proposes comparison mother wavelets for fault classification on hybrid transmission line systems. Hybrid system consists of overhead line and underground cable of 115 kV. ATP/EMTP software has been used for generating fault signals. Then it varies location of fault, fault type and angle. Current signals and zero sequence are analyzed by Discrete Wavelet Transform (DWT) in MATLAB software. DWT decomposes high frequency components from fault signals. Coefficient in scale 1 has been decomposed from Mother Wavelets such as Daubechies (db), Symlets (sym), Biorthogonal (bior) and Coiflets (coif). The coefficient for any mother wavelet has same behavior but different value. Design algorithm for fault classification and compare the result. Therefore, comparison of mother wavelet for fault classification is important to provide the high accuracy. Daubechies (db) can give accuracy more than any mother wavelet. - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Behaviour of interturn fault in power transformer winding using high frequency components of discrete wavelet transform(2012-12-01) ;Klomjit, JittiphongBehaviour of interturn winding fault signals in a three-phase two-winding transformer with delta connected primary and wye connected secondary, using high frequency components of DWT is proposed in this paper. The mother wavelet daubechies4 (db4) is employed to decompose high frequency components from signals. Various case studies have been done including the variation of fault inception angles, fault types, and fault locations. The result will be useful in the development of a fault detecting scheme for power transformer in the future. © 2012 IEEJ Industry Appl Soc. - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Discriminating among inrush current, external fault and internalwinding fault using coefficient of DWT(2012-06-12); ;Klomjit, Jittiphong ;Yodkhuang, Apichart; This paper proposes a technique for discriminating among inrush current, external fault and 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. 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 in the considered system. - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Application of back-propagation neural network for transformer differential protection schemes part 2 identification the phase with fault appearance in power transformer(2012-12-01); ; ;Bunjongjit, Sulee ;Klomjit, JittiphongSuechoey, BoonlertIn this paper, a decision algorithm for identifying the phase with fault appearance of a two-winding three-phase transformer has been proposed. A decision algorithm based on a combination of Discrete Wavelet Transforms and back-propagation neural networks (BPNN) is developed. Daubechies4 (db4) is employed as mother wavelet in order to decompose high frequency components from fault signals. The maximum coefficients of DWT at cycle of phase A, B, C and zero sequence for post-fault differential current are used as input patterns for training process, and the results obtained from the decision algorithm are investigated. Various cases and fault types are studied to verify the validity of the algorithm. The result is found that the proposed decision algorithm can give more satisfactory results. © 2012 IEEE. - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Discriminating among inrush current, external fault and internal fault in power transformer using low frequency components comparison of DWT(2012-12-01); ; ;Klomjit, JittiphongA technique using discrete wavelet transform (DWT) in order to discriminate among inrush current, internal fault, and external fault has been proposed. Daubechies4 (db4) is employed as mother wavelet in order to decompose low frequency components from fault signals. A ratio between per unit differential current and per unit time is calculated and performed as comparison indicator. The results obtained from the proposed technique have good accuracy to discriminating fault in the considered system. © 2012 IEEJ Industry Appl Soc.
