Ngaopitakkul, Atthapol
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Preferred name
Ngaopitakkul, Atthapol
Alternative Name
Ngaopitakkul, A.
Main Affiliation
Email
atthapol.ng@kmitl.ac.th
21 results
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Item type:Publication, Development and Analysis of a Fast-Charge EV-Charging Station Model for Power Quality Assessment in Distribution Systems(2025-09-01); - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Comparative Fault Detection Between DWT and STFT in Overcurrent Relays(2024-01-01); ; This study proposes a protection relay using a microcontroller to detect and classify faults in transmission lines based on the Wavelet transform. An experimental model was constructed from an actual 115 kV transmission system prototype. The current signal was observed based on the fault type, phase, and position. Clark's transform and the discrete Wavelet transform (DWT) were applied to transform signals for analysis. The positive and zero sequences obtained from Clark's transform were used for fault detection and fault classification, respectively. Moreover, the performances between the DWT and the short-time Fourier Transform (STFT) were compared in terms of accuracy and processing time. In addition, the double-detection technique was used to confirm the accuracy of fault detection. Results show that the proposed method is efficient for fault detection and classification. This finding allows the researcher to choose the appropriate analytical method. Moreover, it can also be used as the basis for overcurrent relay algorithm design in the effort to develop more advanced technologies. - 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); ; 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, Behaviour analysis of H-bridge high-voltage capacitor banks fault on 230-kV substation using discrete wavelet transform(2023-11-01); The protection of traditional high-voltage capacitor banks relies on an unbalance relay which operates when an internal fuse is blown. However, the unbalance relay cannot indicate the cause of the fault. Thus, an operator wastes time and human resources investigating the fault issues. In this paper, a fault which occurred in a 230-kV power system of Electricity Generating Authority of Thailand was observed by performing simulations using the Power Systems Computer Aided Design (PSCAD) program. The study system based on the double bus station and 72 MVAR capacitor banks was installed in the form of a back-to-back topology. Three scenarios were considered: normal condition, fault occurrence in one capacitor bank and fault occurrence in both capacitor banks. Current characteristics such as the current phase and difference in unbalance current were considered. In addition, discrete wavelet transform was applied to solve the ambiguity of current generated from the PSCAD. The authors’ results suggest that identifying fault events using a coefficient of wavelet is more efficient than relying on the current amplitude. The findings mentioned in this paper can be applied in a traditional power system protection scheme to enhance a system's reliability. - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Economic Analysis of Improving the Energy Efficiency of Nanogrid Solar Road Lighting Using Adaptive Lighting Control(2020-01-01); This paper presents a road lighting control system that uses a light-dependent resistor sensor cooperating with an Internet protocol camera to the lower energy consumption during unnecessary use of a lighting system. A microcontroller was used as a control circuit to automatically control the brightness of a light-emitting diode (LED) luminaire, increasing or decreasing the brightness depending on traffic density. The proposed lighting control system was integrated into a nanogrid solar road lighting system and analysed through an experimental setup. Furthermore, nanogrid solar road lighting systems in LED solar stand-alone and grid-connected operations, with and without the proposed lighting control, were investigated and compared with a conventional existing road lighting system in terms of economic feasibility, based on the following indicators: discounted payback period, net present value, internal rate of return, and profitability index. The results indicate that the use of the Internet protocol camera with the LED sensor can automatically control the on/off state or illuminance levels of the LED luminaire, thereby lowering the energy consumption of the road lighting system when lighting is not required. The economic assessment results indicate that the nanogrid solar road lighting system in LED solar stand-alone and grid-connected road lighting modes exhibit feasibility for investment; the latter provides more economic feasibility. However, when the proposed lighting control is included, the nanogrid solar road lighting system in both modes have lower initial investment costs and save more energy. Consequently, the economic results are improved. The use of the proposed lighting control is thus economically feasible for road lighting systems. - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Analyzing the Characteristics of Faults in a Transmission Line and High Voltage Capacitor Banks in a 115-kV-Power System Using Discrete Wavelet Transform(2022-01-01) - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Feasibility Study on Installation of Rooftop Photovoltaic System in Complied with Thailand Energy Building Code(2020-08-24) - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Study on Installation of Neutral Ground Resistance in Very Small Power Plant Transformer(2022-01-01); ; Faults in the distribution system of the Thai electrical system occur frequently. Such faults directly affect the protective equipment of the distribution system. The protective device disconnects the circuit unnecessarily on many occasions because it detects a higher current than expected. In this study, a 22-kV distribution system and a very small power plant (VSPP) were connected. The system consists of two feeders. Feeder 1 supplies electricity directly to the load; a fault was enforced in this feeder. Feeder 2 supplies electricity directly to the load; the VSPP was connected to this feeder. The fault in Feeder 1 was simulated, and the behavior of the defense system was studied. Unnecessary disconnection of the VSPP circuit took place because the high fault current caused the overcurrent protection relay to operate instantaneously. Therefore, a neutral ground resistance was installed at the VSPP transformer to reduce the fault current, extend the relay operating time to the delay range, and reduce unnecessary disconnections of the overcurrent protection relay of the VSPP. In addition, when a fault occurs in the distribution system, the faulted phase voltage decreases, whereas the non-faulted phase voltage increases. Surge arresters and voltage transformers must be able to withstand an increase in voltage. This is also explained and discussed in this paper. - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Financial feasibility of electric vehicle charging stations in Thailand: An analysis of operational models and energy costs(2025-07-01); Despite the increasing demand for electric vehicles (EVs) and the associated charging stations, the variances in EV charging station models and diversity of energy costs have not been effectively studied to date. Therefore, this study examines the financial viability of EV charging stations in Thailand by analysing the effects of operational models, charger counts, and fluctuating energy costs. The profitability, payback periods, and investment returns of various types of EV charging stations are evaluated by combining financial analysis tools and historical energy cost data. The results indicate that small-scale charging stations with 1–3 chargers demonstrate superior financial viability, achieving internal rates of return (IRR) of 24.18–39.86 % and payback periods ranging from 3 to 4 years, depending on the tariff model. By contrast, stations with more than three chargers experience extended payback periods, with some configurations failing to recover investment within the project duration owing to increased capital expenditures and operational costs. This study also emphasises the critical role of dynamic energy pricing in the financial modelling of charging stations. Electricity costs vary significantly between conventional and low-priority stations, with energy costs for conventional stations being up to 23 % higher. The financial feasibility of EV charging stations in Thailand presents competitive advantages in terms of investment attractiveness and return on capital compared with higher energy cost regions with fewer financial incentives. The findings have significant implications for station operators, investors, and policymakers, highlighting the need for strategic planning and adaptive pricing strategies in EV charging infrastructure development. - Some of the metrics are blocked by yourconsent settings
Item type:Publication, An approach to energy conservation in lighting systems using luminaire-based sensor for automatic dimming(2025-12-01);