Ngaopitakkul, Atthapol
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Preferred name
Ngaopitakkul, Atthapol
Alternative Name
Ngaopitakkul, A.
Main Affiliation
Email
atthapol.ng@kmitl.ac.th
20 results
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Item type:Publication, Classification of Capacitor Bank Switching Using Fuzzy Interference Systems in 230 kV Substation(2024-01-01); ; ; Lertwanitrot, PraikanokFlexible 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. - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Effects of Conditional Changes on High-Voltage Direct Current Transmission Line Characteristic(2022-01-01); ; - Some of the metrics are blocked by yourconsent settings
Item type:Publication, A phase diagram approach to the detection and location of faulty capacitor units in A 115-kV capacitor bank based on unbalanced current arguments(2023-03-01); - 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, An Evaluation Study on Electric Appliance Characteristics and Load Patterns in Residential Buildings(2026-01-01); - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Wavelet Transform and Artificial Intelligence for Unbalanced Current Protection of 230kV Capacitor Switching Transient Inrush Current(2021-01-01); High transient inrush currents from back-to-back capacitor switching can cause the maloperation of protective relays, especially the instantaneous overcurrent (50) and unbalanced current protection relays (60C). This paper presents a combination of discrete wavelet transforms and artificial intelligence as an efficient technique to analyze the inrush current switching. The discrete wavelet transform is used to detect and classify either isolated or back-to-back capacitor switching transient signals. After that, the output from wavelet coefficients acts as the artificial intelligence input for discriminating the 6-difference cases of transient inrush current mitigation methods by using the combination of discrete wavelet transform and fuzzy inference system and discrete wavelet transform and probabilistic neural network. The proposed technique of discrete wavelet transform for detection and classification shows enhanced performance accuracy of 100 %. The fuzzy inference system and probabilistic neural network that can discriminate the inrush current mitigation methods have a high accuracy of 90.57 % and 96.72 %, respectively. - 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, Design and techno-economic evaluation of a nanogrid system for a small-scale public railway station building in Thailand(2025-12-01); - Some of the metrics are blocked by yourconsent settings
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); ; Lertwanitrot, PraikanokThis 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. - Some of the metrics are blocked by yourconsent settings
Item type:Publication, An Approach for Voltage Drop Improvement in Distribution Line Using High-Voltage Capacitor Bank(2025-01-01);