KMITL

Permanent URI for this communityhttps://dspace.kmitl.ac.th/handle/123456789/1

Browse

Search Results

Now showing 1 - 10 of 27

Some of the metrics are blocked by your
consent settings
The Design and Evaluation of Nanogrid-Based Solar Photovoltaic Light-Emitting Diode Street Lighting Systems: A Techno-Economic and Voltage Drop Analysis for Secondary Roads in Thailand
(2026-05-01)
Bunjongjit, Sulee
;
Wang, Hongyan
;
Huang, Yansheng
;
Songsukthawan, Panapong
;
Yoomak, Suntiti
Street lighting systems are essential for ensuring nighttime road safety and visibility. The integration of solar photovoltaic (PV) systems into street lighting infrastructure improves energy efficiency and sustainability; however, the mismatch between daytime energy generation and nighttime lighting demand requires effective energy management solutions. In addition, long-distance electrical connections introduce voltage drop constraints, which are often overlooked in conventional design approaches. This study addresses the integration of lighting design, electrical constraints, and techno-economic performance in nanogrid-based LED street lighting systems for secondary roads. A unified framework is developed to evaluate lighting performance, PV–battery sizing, voltage drop behavior, and lifecycle cost under different system architectures. Optimal pole spacing and luminaire ratings are determined using DIALux, while PV–battery configurations are optimized using HOMER Pro based on site-specific solar irradiance. The analysis focuses on voltage drop as the key electrical constraint and examines its impact under decentralized and centralized nanogrid configurations (25%, 50%, and 100%) in both stand-alone and grid-connected modes. The results show that increasing centralization reduces component redundancy but significantly increases cable length, conductor sizing, and infrastructure cost. A techno-economic assessment with lifecycle cost and sensitivity analysis indicates that a 25% centralized configuration reduces total system cost by approximately 23% compared to fully decentralized systems while avoiding excessive cabling costs. These findings demonstrate that voltage drop and electrical infrastructure constraints play a decisive role in determining optimal system design, highlighting the importance of system-level integration rather than isolated optimization of lighting or energy components.
Some of the metrics are blocked by your
consent settings
Comparative Study between On- and Off-Grid Photovoltaic to Reduce Peak Demand in Residential Houses
(2026-01-01)
Jettanasen, Chaiyan
;
Sottiyaphai, Chayanut
;
Bunjongjit, Sulee
;
Songsukthawan, Panapong
;
Phannil, Natthanon
This study proposes a programmable logic controller (PLC)-based energy management system integrated with an off-grid photovoltaic (PV) system and battery storage to reduce residential peak demand. The proposed system dynamically manages power supply between the distribution grid, PV generation, and battery storage based on real-time power demand measurements. When the measured power exceeds a predefined threshold, stored renewable energy is utilized to support high-load conditions and mitigate peak demand. Experimental results obtained from a residential-scale test system demonstrate that the proposed off-grid PV system with PLC control can reduce peak demand by up to 29.68% and 15.57% under office-working and work-from-home scenarios, respectively, compared with conventional grid supply and on-grid PV systems without storage. In addition, the system achieves electricity cost reductions of up to 13.63% under Time-of-Use tariffs and up to 11.42% under normal electricity rates, depending on load behavior. These results indicate that integrating PLC-based control with off-grid PV and battery storage can effectively mitigate residential peak demand and reduce electricity expenses under realistic operating conditions.
Some of the metrics are blocked by your
consent settings
Transient Analysis to Distinguish Mechanically Switched Capacitors Using Discrete Wavelet Transform and Artificial Intelligence
(2026-01-01)
Thongsuk, Surakit
;
Bunjongjit, Sulee
;
Yoomak, Suntiti
;
Ananwattanaporn, Santipont
;
Jettanasen, Chaiyan
Capacitor banks are widely used in modern power systems for reactive power compensation and voltage regulation. However, switching operations of mechanically switched capacitors (MSCs) can generate transient phenomena, such as inrush currents, which may resemble fault currents and lead to misoperation of protection systems. Therefore, accurate detection and classification of transient events are essential for reliable system operation. This study proposes a hybrid approach for transient signal analysis and classification by integrating the discrete wavelet transform (DWT) with artificial intelligence (AI) techniques, including probabilistic neural networks and fuzzy inference systems (FIS). The DWT performs time–frequency analysis to extract multi-scale wavelet features from three-phase current signals. The proposed method enables both discrimination between inrush and fault currents and multi-class classification of transient events among six capacitor switching conditions, namely base case, pre-insertion resistor, pre-insertion inductor, current limiting reactor, 6% reactor, and synchronous closing. The methodology is validated using PSCAD/EMTDC simulations under isolated and back-to-back capacitor switching scenarios. The results demonstrate that the proposed DWT–AI approach achieves high classification accuracy exceeding 95%, outperforming conventional methods based on DWT alone and DWT combined with FIS. Furthermore, the proposed method improves protection system performance by reducing false tripping caused by transient inrush currents, while maintaining reliable fault detection capability. The findings confirm that integrating time–frequency signal processing with AI-based classification provides an effective and practical solution for transient event discrimination in MSC capacitor bank systems.
Some of the metrics are blocked by your
consent settings
Design and techno-economic evaluation of a nanogrid system for a small-scale public railway station building in Thailand
(2025-12-01)
Ngaopitakkul, Atthapol
;
Songsukthawan, Panapong
;
Bunjongjit, Sulee
;
Sreewirote, Bancha
;
Yoomak, Suntiti
In Thailand, numerous small-scale public facilities continue to rely on the electrical grid. The integration of renewable energy sources such as photovoltaic (PV) and wind power offers a sustainable alternative; however, their inherent intermittency necessitates advanced solutions such as nanogrid systems, which enable localized energy generation, storage, and management to enhance reliability and autonomy. This study develops a nanogrid-based energy management system for Hua Takhe train station, Thailand, by integrating photovoltaic (PV) panels, wind turbines, and battery energy storage systems (BESS). Using HOMER Pro, multiple configurations were simulated and evaluated across key financial indicators, including Payback Period (PB), Internal Rate of Return (IRR), Return on Investment (ROI), Net Present Value (NPV), and Levelized Cost of Electricity (LCOE). The analysis framework further incorporates economic feasibility evaluation, sensitivity and scenario analysis, and long-term performance and life cycle evaluation, thereby ensuring that both short-term financial viability and long-term sustainability are comprehensively assessed. Results show that PV-dominant nanogrid systems, particularly at larger scales, represent the most practical and cost-effective pathway for sustainable electrification of public facilities in Thailand. The 30PV Nanogrid achieves the most favorable balance between cost and performance, with a NPV of 23,925 USD, a LCOE of 0.04 USD/kWh, a PB of 7 years, an IRR of 13 %, and a ROI of 215 % under long-term life-cycle evaluation. In comparison, the 15PV Nanogrid proves economically marginal, with NPV falling to –9117 USD, PB extending beyond 20 years, IRR turning negative (–5 %), and ROI declining to –40 %, confirming that small-scale nanogrids cannot offset the costs of ESS and hybrid inverters.
Some of the metrics are blocked by your
consent settings
Auto-tuned Active Filter Design for Lighting System in Buildings
(2025-01-01)
Phannil, Natthanon
;
Bunjongjit, Sulee
;
Ananwattanaporn, Santipont
The lighting system is a continuously used energy system found in all buildings. This system is highly complex as it includes various types such as incandescent bulbs, fluorescent tubes, HID lamps, and LEDs. These types of loads consist of many electronic components and are significant sources of Auto-Tuned Active Filter signals. These harmonic signals directly affect protective devices and electronic equipment in the building's electrical system. Therefore, reducing the harmonic signals generated by the lighting system is crucial for buildings. Generally, harmonic reduction can be achieved by installing one of three types of filters: active, passive, and hybrid. This research presents the design of an auto-tuned active filter using the MATLAB Simulink and tests it using four lighting load cases. The designed circuit can effectively reduce harmonic signals while also improving the energy efficiency of the building.
Some of the metrics are blocked by your
consent settings
Energy Harvesting from Railway-Induced Vibrations Using Piezoelectric Nanogrid Systems
(2025-01-01)
Jettanasen, Chaiyan
;
Songsukthawan, Panapong
;
Yoomak, Suntiti
;
Bunjongjit, Sulee
;
Ngaopitakkul, Atthapol
This paper investigates the feasibility of piezoelectric nanogrid systems designed to harvest mechanical energy from vibrations induced by passing trains. Two membrane-based piezoelectric module mounting configurations - sleeper-mounted at a 5 cm offset from the rail, and recessed side-mounted - were rigorously analyzed using Finite Element Method (FEM) simulations for structural durability and energy-harvesting performance. Realistic excitation waveforms, synthesized from FEM modal characteristics combined with actual field measurement data, were employed in detailed MATLAB/Simulink electrical simulations. Results demonstrated a superior electrical current output from the side-mounted configuration (2.2839 A) compared to the sleeper-mounted arrangement (1.30195 A). A practical assessment revealed that only 9 side-mounted or 16 sleeper-mounted modules are necessary to effectively charge a standard 12V 20Ah LiFePO4 battery. Moreover, daily accumulated energy of approximately 68-70 Wh could reliably power essential low-power devices at railway stations, confirming the proposed piezoelectric nanogrid system's viability as a robust, efficient, and scalable energy-harvesting solution.
Some of the metrics are blocked by your
consent settings
An Approach for Voltage Drop Improvement in Distribution Line Using High-Voltage Capacitor Bank
(2025-01-01)
Songsukthawan, Panapong
;
Ananwattanaporn, Santipont
;
Thongsuk, Surakit
;
Phannil, Natthanon
;
Bunjongjit, Sulee
Distribution line voltage drops cause power losses and a general decline in the efficiency of the electrical power system. In this study, PSCAD software is used to evaluate the elements that impact the voltage drop in the distribution line, including distribution line length, electric load power factor, and electric load capacity, both with and without capacitor bank installation. The 22-kV overhead distribution line in Thailand served as the basis for the simulation model’s creation. It has been suggested to install capacitor bank-based techniques to increase voltage on distribution lines. The findings show that the voltage drop is significantly influenced by the distribution line distance, electric load power factor, and electric load capacity. The voltage drop can be minimized to the greatest extent by properly arranging capacitor banks.
Some of the metrics are blocked by your
consent settings
An approach to improve grounding resistance characteristic in existing 115 KV transmission towers
(2024-12-01)
Pothisarn, Chaichan
;
Kulwongwit, Wiwat
;
Lertwanitrot, Praikanok
;
Bunjongjit, Sulee
;
Ngaopitakkul, Atthapol
Effective grounding can attenuate fault currents and reduce damage to power system equipment, making the grounding system a crucial protection scheme. Generally, the ground resistance is set to a value less than 10 Ω. However, in practice, it is difficult to achieve this in certain areas, such as mountains, plains, and swamps. To address this problem, this study analyses the (1) actual footing resistance, (2) ground resistivity, and (3) ground length of transmission towers located in specific areas. Non-linear factors, impedance, and coupling effect are considered instead of traditional variables. A grounding design algorithm is proposed based on the ATPDraw program. Simulation results are applied to the 115 kV real-world system of the Electricity Generating Authority of Thailand. The grounding system exhibits a satisfactory performance improvement, as evidenced by comparisons between simulation and actual measurements. The findings are useful for implementing future improvements in grounding protection schemes.
Some of the metrics are blocked by your
consent settings
Downtime Reduction with Fast Restart Function in a Beverage Production System
(2023-01-01)
Jettanasen, Chaiyan
;
Phannil, Natthanon
;
Yoomak, Suntiti
;
Thongsuk, Surakit
;
Bunjongjit, Sulee
Bottled-beverage production systems require considerable machinery and sophisticated control systems. A malfunction in the production system can result in machine stoppages, thereby decreasing productivity and resulting in the production output not meeting the required target. Therefore, the problem of frequent stoppages of the production system must be resolved. The ‘Fast Restart Function’ is a proposed feature that can help reduce machine downtime by decreasing the time required for the product to drain from the conveyor. In this study, using this strategy, the investigated manufacturing system’s efficiency increased from 86.81% to 90.29%, enabling an increase in the average production capacity by 27,187 bottles per day, i.e., a 3.48 percent increment of the daily capacity. When employed in inefficient production systems or systems facing frequent shutdowns, this system is of considerable value for mitigating production stoppages.
Some of the metrics are blocked by your
consent settings
Effects of Conditional Changes on High-Voltage Direct Current Transmission Line Characteristic
(2022-01-01)
Pothisarn, Chaichan
;
Ngaopitakkul, Atthapol
;
Leelajindakrairerk, Monthon
;
Phannil, Natthanon
;
Bunjongjit, Sulee
The high-voltage direct current (HVDC) transmission system, which links the Gurun Substation of the National Electric Authority of Malaysia (Tenaga Nasional Berhad, TNB) with the Khlong Ngae Station of the Electricity Generating Authority of Thailand (EGAT), has been extensively researched to achieve the highest quality because it is the largest of its kind in Thailand, and there is a plant to expand its transmission power. However, the impact on the whole system is under-researched. To study and develop this system, the HVDC transmission line is modelled with the MATLAB/Simulink program and a laboratory setup to investigate the effect of transmission line distance, load power, and voltage on power loss, voltage drop, and waveform. The HVDC transmission line parameters are calculated from the actual transmission line parameters and converted to the simulation model parameters using the per-unit method. The model is verified and tested by the simulation program before creating the experimental setup. The simulation and experimental results demonstrate the effects of changing system conditions via the three aspects. All the three conditions directly affect the HVDC transmission line; nevertheless, they affect each aspect differently.

KMITL

Browse

Filters

Settings

Sort By

Results per page

Search Results