Now showing 1 - 10 of 26
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    Item type:Publication,
    Classification of Capacitor Bank Switching Using Fuzzy Interference Systems in 230 kV Substation
    (2024-01-01)
    Patcharoen, Theerasak
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    Lertwanitrot, Praikanok
    Flexible AC transmission systems are used for enhancing the stability, transmission efficiency, and reliability of AC grids. Additionally, the most cost-effective devices for compensating reactive power are Mechanically Switched Capacitors (MSCs). This study proposes a novel algorithm for detection and capacitor bank switching transient signals in MSC, to prevent the protective relay maloperation by these transients. The Discrete wavelet transform (DWT) is used for effective time-frequency analysis and detection of measured three-phase current signals. DWT extracts the detailed wavelet coefficients of current signals at levels 1 to 30. In addition, the fuzzy inference system (FIS) has been used to determine the type of switching transient. The proposed combination of FIS and DWT has been tested on 230 kV substation and the result demonstrated precision for the identification and classification of both transient signals in MSC with 88% accuracy rate.
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    Design and application of daylight-based lighting controller on LED luminaire
    (2020-05-01)
    Bunjongjit, Sulee
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    Patcharoen, Theerasak
    This paper proposes a control circuit for Light Emitting Diode (LED) luminaire based on the amount of daylight. This system uses both natural daylight and artificial light from a luminaire to reach the desired illuminance on a working plane. The control circuit operates by receiving an illuminance value from a light sensor and comparing it with a set value in the microcontroller before limiting the light intensity of LED by sending a control Pulse Width Modulation (PWM) signal to the LED driver. In the experimental setup, the controller and a physical model of a working space were built in order to field test the LED daylight control circuit. Electrical characteristics such as voltage, current, and power were measured with a power meter. Illumination characteristics in terms of illuminance on a working plane were determined using a lux meter. The results from actual field tests revealed that this LED control circuit was able to reduce the power consumption of the lighting system while keeping the illuminance on the working plane at the standard value. Both simulation results and the actual experiment of the control circuit proved that it could be used to improve the energy efficiency of both newly installed and retrofitted lighting systems.
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    Item type:Publication,
    Evaluation of Light-Emitting Diode Luminaire For Two-Lanes Roadway Lighting System
    (2024-01-01)
    Wannapasert, Padungsak
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    Lighting systems for roadways are an important aspect of the transportation system in terms of safety and providing comfort for drivers. Conventional lighting systems use high-pressure sodium luminaires, which consume a lot of energy. This paper proposes an evaluation of roadway lighting using lightemitting diodes (LEDs) as luminaires. The paper uses a two-lane road as a case study and simulates the lighting parameters using DIALux software. The case study varies the wattage of the luminaires, pole distances, and pole arrangements, while keeping the pole specifications fixed. The parameters under consideration include illuminance, luminance, and uniformity on the road surface. Additionally, the results are compared with international criteria standards to confirm that the selected LED luminaires can provide the necessary lighting quality for road usage. The results show that LED luminaires can provide lighting quality within standard criteria. However, different pole arrangements require different levels of wattage and pole distances. Therefore, the selection of LEDs needs to match the design of pole distances and arrangements to provide sufficient roadway lighting.
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    Development and Analysis of a Fast-Charge EV-Charging Station Model for Power Quality Assessment in Distribution Systems
    (2025-09-01)
    Chiradeja, Pathomthat
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    Srisuksai, Panu
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    Klomjit, Jittiphong
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    With 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.
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    Comparative Fault Detection Between DWT and STFT in Overcurrent Relays
    (2024-01-01)
    Chiradeja, Pathomthat
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    Lertwanitrot, Praikanok
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    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.
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    Analysis of Investment Feasibility for EV Charging Stations in Residential Buildings
    (2025-09-01)
    Chiradeja, Pathomthat
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    Sottiyaphai, Chayanut
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    Klomjit, Jittiphong
    This 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.
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    Item type:Publication,
    An Evaluation Study on Electric Appliance Characteristics and Load Patterns in Residential Buildings
    (2026-01-01)
    Thongsuk, Surakit
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    Songsukthawan, Panapong
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    Sottiyaphai, Chayanut
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    Energy usage in residential buildings has been constantly increasing as work-from-home trends continue to maintain popularity. To improve energy efficiency, the load profile and electric appliances in households need to be established and analyzed. This study aims to evaluate the characteristics of electric appliances that are commonly used in residential buildings under various operating conditions. An experimental setup with household electric appliances was built, and power quality meters were installed to assess the patterns under various operating conditions. In addition, the usage patterns were used to construct the daily load profile and analyze the energy consumption in residential buildings. The results demonstrate that load patterns constructed from actual measurements can achieve an accurate depiction of energy usage in residential buildings. The obtained load profile can be used in load control to improve energy efficiency and the application of renewable energy in demand reduction.
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    Impact of Wind Power Generation Sizing on the Characteristic of Distribution System Under Fault Condition
    (2022-01-01) ;
    Leelajindakrairerk, Monthon
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    Songsukthawan, Panapong
    In the recent decade, there has been a rising concern in energy consumption and environmental issues. This trend has shifted the electric authority to focus from fossil fuel to renewable energy. The distributed generation (DG) using a renewable energy source has been raising. The presence of DG can cause using renewable energy sources to cause a technical issue on system protection and operation. This paper aims to study the impact of different DG size installations on the distribution system in terms of the system characteristics. The study is done in both normal conditions and in cases of fault occurrence. The system using in this research is a 22-kV distribution system consists of Wind Power Generation as the DG connected into the distribution line that modeled after part of the Provincial Electricity Authority (PEA) in the northern part of Thailand. The simulation was done using PSCAD software. The result from simulation reveals the impact of DG on the distribution system characteristics in terms of significant change in the measured current and voltage signal. Thus, the analysis of the impact of DG on the system must be done to ensure the reliability of the power system.
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    Item type:Publication,
    Power Quality Improvement Based on Active Harmonic Filter in 24 kV Liquefied Natural Gas Industrial Plant’s Photovoltaic System
    (2026-06-01) ;
    Patcharoen, Theerasak
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    Lothongkam, Chaiyaporn
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    Lertwanitrot, Praikanok
    This paper presents a case study demonstrating the power quality improvements in a 24 kV distribution system at a liquefied natural gas (LNG) industrial plant with variable speed drives (VSDs), the conventional capacitor bank, and a rooftop solar photovoltaic system. Solar photovoltaic (PV) inverters can supply harmonic currents to the grid, potentially affecting the system and causing maloperation of sensitive equipment in both the utility systems and neighboring industries connected to it. Therefore, the installation of shunt active power filters (APFs) in a 400 V system was proposed in this study. The installed locations were varied, and the corresponding power qualities were analyzed. The results were examined in terms of design and harmonic elimination. Simulations were conducted using the PSCAD/EMTDC software version 4.5. The power quality simulation and field measurement results after the APF installation were compared to demonstrate the effectiveness of the proposed solutions. The addition of APFs was found to improve the power quality. In addition to the mechanism analysis, the economic feasibility of the proposed approach was investigated. The costs of APF installation in various locations were analyzed. The results show that the proposed method can improve the power supply at a reasonable price. This work contributes to sustainable industrial energy systems by improving the reliability and power quality of photovoltaic-integrated electrical networks, thereby supporting higher penetration of renewable energy resources and stable low-carbon industrial operation.
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    Financial feasibility of electric vehicle charging stations in Thailand: An analysis of operational models and energy costs
    (2025-07-01)
    Chiradeja, Pathomthat
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    Sottiyaphai, Chayanut
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    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.