Kunakorn, Anantawat
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Preferred name
Kunakorn, Anantawat
Alternative Name
Kunakorn, A.
Kunakorn, Anatawat
Main Affiliation
Email
anantawat.ku@kmitl.ac.th
5 results
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Item type:Publication, Comparative Fault Detection Between DWT and STFT in Overcurrent Relays(2024-01-01) ;Chiradeja, Pathomthat; ;Lertwanitrot, Praikanok; 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, Transient Analysis to Distinguish Mechanically Switched Capacitors Using Discrete Wavelet Transform and Artificial Intelligence(2026-01-01) ;Thongsuk, Surakit ;Bunjongjit, Sulee; ; 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, Application of Neutral Grounding Resistor in High Voltage Photovoltaic Solar Substation System(2025-01-01) ;Pothosarn, Chaichan ;Patcharoen, Theerasak ;Srisuksai, Panu; Faults in a distribution system with additional renewable energy sources can lead to unnecessary operation of protection devices due to higher detected fault currents compared to conventional systems. In addition, the voltage at the point of interconnection may temporarily drop to a low level, causing inverter-based generators to disconnect from the system. This study, therefore, proposes an investigation into the use of neutral grounding resistors in a 115 kV high-voltage (HV) substation unit located within a solar power generation system. The approach aims to limit ground fault current and reduce temporary voltage sags to maintain the connection status of inverter and ensure compliance with low voltage fault ride-through (LVRT) capability. The case study is modeled after an actual grid network consisting of two feeders, with one feeder connected to a solar power plant. PowerFactory DIgSILENT software is used to simulate the system and analyze the impact of various neutral grounding resistance values. The results of this study can be applied to the selection of neutral grounding resistors for system, helping to reduce fault current, extend relay operating time within the allowable delay range, and minimize unnecessary tripping of overcurrent protection relays in the system. - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Dielectric Response Analysis on Artificial ZnO Surge Arrester Degradation Using Polarization and Depolarization Current Based Method(2024-01-01) ;Chuayin, Chaitawat; ;Zinck, Matthieu ;Methavithit, WinaiSuksagoolpanya, SuthatThis paper presents an alternative method to investigate the problems of surge arrester based on dielectric response analysis. The study is made using a 21-kV, 25-kA station class surge arrester to be test specimens, the former Zinc Oxide (ZnO) varistors inside were removed and replaced with artificial degraded ZnO varistors (impulse ageing, tracking problems, moisture ageing under wet and dry condition and cracking ZnO varistors). The experiments are carried out by Polarization and Depolarization Current (PDC) measurement. The test result analyses were proposed in terms of both the time domain and frequency domain. The measurement results show significant differences in dielectric response characteristics between healthy surge arresters and aged surge arresters. In addition, the dielectric response analysis tends to characterise the problems of surge arrester i.e., conduction problems and polarization problems which will be further discussed in this paper. - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Effective design of a two-stage surge protective device for AC low voltage system protection(2024-01-01); ;Paophan, BusayapolThis study describes a useful technique for the optimal design of a two-stage surge protective device in the mitigation of overvoltage in low-voltage AC power systems. Two metal oxide varistors (MOVs) and a single inductor are used to form the protection circuit. A genetic algorithm based on MATLAB software is applied for the determination of the proper inductance. The conditional optimization is set to minimize the overvoltage generated by a combination wave generator. Meanwhile, the proposed SPD does not affect the voltage drop in the power frequency voltage (50 Hz). In the simulation process, the current-voltage (I-V) characteristics of SPDs are collected from the manufacturer's datasheet. The simulation results with the proposed circuit are confirmed by those calculated by ATP/EMTP software. Experiments for validation of the proposed approach were also carried out in a high-voltage laboratory to check the performance of over-voltage mitigation. According to the experimental and computational results, the proposed circuit performs well in terms of over-voltage mitigation. It has been confirmed that the presented approach is attractive for overvoltage mitigation in low-voltage AC power systems.
