Pothisarn, Chaichan
Loading...
Preferred name
Pothisarn, Chaichan
Alternative Name
Pothisarn, C.
Main Affiliation
Email
chaichan.po@kmitl.ac.th
30 results
Now showing 1 - 10 of 30
- 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, Relation among velocity of lightning travelling wave, lightning stroke current, and tower footing resistance to study back-flashover on the insulators in transmission tower(2013-01-01); Thongsuk, S.This paper studies the impact of back-flashover on the insulators with various velocities of lightning travelling wave, the lightning stroke current, and the tower footing resistance. The impedance of transmission tower section such as top tower, upper phase, middle phase, and lower phase that is calculated with lightning velocity dependent parameters is also considered. The velocity of lightning travelling wave at 300 m/μs and 200 m/μs is compared to consider back-flashover including maximum voltage at the cross arm and voltage across insulators. The results is shown that the velocity of lightning travelling wave plays an important role for the back-flashover voltage across insulator as well as the tower footing resistance and the lightning stroke current. © 2013 Praise Worthy Prize S.r.l. - All rights reserved. - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Impact of lightning impulse voltage waveshape front time between 1.2/50 μs and 4/50 μs on back-flashover voltage across insulator of 230 KV transmission tower(2014-02-04); This paper is a study of the behavior of back-ashover on the insulators with various lightning voltage waveshapes. The simulated lightning strikes on high voltage 230 kV transmission towers using Alternative Transients Program/Electromagnetic Transients Program (ATP/EMTP) to consider back-ashover voltage across insulators. The standard of lightning voltage waveshape (1.2/50 μs) will be compared with the other lightning voltage waveshape front time (4/50 μs) in this paper. The results are shown that the lightning voltage waveshape plays an important role for the back-ashover voltage across insulators as well as the tower footing resistance and the lightning stroke current. © 2014 ICIC International. - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Performance and electromagnetic interference mitigation of DC-DC converter connected to photovoltaic panel(2019-11-01); Renewable energy has been rapidly increased in terms of installed capacity. However, the electronic components inside such a system can cause a serious threat such as Electromagnetic Interference (EMI) to nearby sensitive devices/equipment. This paper aims to study on performance of DC-DC boost converter connected to photovoltaic panel and how to reduce EMI emissions issued in the system. A passive EMI low-pass filtering is one of various mitigation techniques. The designed converter connected to photovoltaic panel and EMI filter are tested in both simulation software and field testing by using EN55022 standard as a reference. - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Transient Analysis to Distinguish Mechanically Switched Capacitors Using Discrete Wavelet Transform and Artificial Intelligence(2026-01-01); ; 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 yourconsent settings
Item type:Publication, Identification of fault location for simultaneous fault in distribution system using discrete wavelet transform(2011-04-01); ; ; Apisit, C.Currently, the most effective technique for identifying fault location, based on a travelling wave, has been proposed in several research papers. However, the effects of simultaneous faults have been neglected. In order to overcome this problem, a new algorithm will be developed in order to predict fault location precisely. This paper presents a technique to detect fault locations, during simultaneous fault, in an underground distribution system using discrete wavelet transform (DWT). The DWT is used to detect the high frequency components. The time that the fault signal uses to reach the ends of the distribution line is considered, then, applied so that the distance of fault can be calculated. The result is found that the proposed algorithm gives satisfactory both in case of single fault and simultaneous fault. ICIC International © 2011. - 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.