Kunakorn, Anantawat
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Preferred name
Kunakorn, Anantawat
Alternative Name
Kunakorn, A.
Kunakorn, Anatawat
Main Affiliation
Email
anantawat.ku@kmitl.ac.th
73 results
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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, Studies of Electrical and Thermal Characteristics of Natural Ester Immersed Transformer Compared with Mineral Oil Immersed and Palm Oil Immersed Transformer(2018-11-14) - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Frequency dependence parameter analysis of underground cables with and without joint(2018-06-29); This paper represents the dielectric investigation of XLPE power cables with and without cable joint (premolded joint) by using polarization and depolarization current (PDC) measurement. To investigate the polarization phenomena of the underground cable (case 1) and the underground cable with the premolded joint (case 2), the XLPE cables with the cross-section area of 240 mm<sup>2</sup> and 5 m long with rate voltage of 12/20(24) kV with and without premolded joint were used in the experiment. In this research work, the DC voltage of 1,000V was applied to insulation system for measuring polarization current, i<inf>pol</inf>(t). Then, suddenly disconnected the DC applied voltage source to short circuit the tested cable to measure depolarization current, i<inf>dep</inf>(t), In case 1, the PDC measurement was only for 100 seconds due to its homogeneous insulation of XLPE cable; only conduction current and interfacial polarization current with short relaxation time existed. In case 2, the PDC measurement was done for 2,000 seconds. In this case the polarization current was from XLPE cable mentioned and the interfacial polarization current from the barrier between XLPE cable and cable joint. From the experiment, the frequency dependence of the complex capacitance and dielectric dissipation factor of the underground cable and the underground cable with the premolded joint were analyzed. It is found that the trend of real part of the complex capacitance and the conduction loss of both case studies is not much different. However, the trend of imaginary part of the complex capacitance and polarization loss of both case studies is clearly different. Two peaks of imaginary parts of complex capacitance and polarization loss of the underground cable with joint is from XLPE and the junction of XLPE and joint. - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Impact on Protective Device Sequence of Operation in Case Distributed Generation Integrated to Distribution System(2023-07-01); ; This study aims to evaluate the impact of the distributed generator (DG) connection to the grid. The simulated results present the parameters of the system required to install DG on the end of the main distribution feeder. Various parameters, such as voltage, current, and protective relay coordination are modelled after the actual provincial electricity authority (PEA) distribution system. Various case studies compared the coordination without and with DG connections to the grid by finding the difference of protective devices. The results indicate that the malfunction can be fixed in order of priority protective devices, which operate according to the parameter setting. Additionally, the coordinate functions between the recloser and fuse devices in both phase and ground configurations in the operating zone prevented the drop-out fuse melting or burning out. Based on the result, this problem is fixed by providing a directional recloser device and increasing the fuse-link rated with 40k installation for replacing the conventional sizing, which can improve the performance in case of fault occurrence to investigate the reliability and stability of the distribution system. - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Effective simulation approach for lightning impulse voltage tests of reactor and transformer windings(2020-10-16); In this paper, an effective simulation method for lightning impulse voltage tests of reactor and transformer windings is presented. The method is started from the determination of the realized equivalent circuit of the considered winding in the wide frequency range from 10 Hz to 10 MHz. From the determined equivalent circuit and with the use of the circuit simulator, the circuit parameters in the impulse generator circuit are adjusted to obtain the waveform parameters according to the standard requirement. The realized equivalent circuits of windings for impulse voltage tests have been identified. The identification approach starts from equivalent circuit determination based on a vector fitting algorithm. However, the vector fitting algorithm with the equivalent circuit extraction is not guaranteed to obtain the realized equivalent circuit. From the equivalent circuit, it is possible that there are some negative parameters of resistance, inductance, and capacitance. Using such circuit parameters from the vector fitting approach as the beginning circuit parameters, a genetic algorithm is employed for searching equivalent circuit parameters with the constraints of positive values. The realized equivalent circuits of the windings can be determined. The validity of the combined algorithm is confirmed by comparison of the simulated results by the determined circuit model and the experimental results, and good agreement is observed. The proposed approach is very useful in lightning impulse tests on the reactor and transformer windings. - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Study of a partial discharge location technique for power cables using high frequency current transducer(2018-11-01); ; Pumyoy, SuparatIn this paper, a partial discharge location technique for power cables was studied. PD signals are measured by high frequency current transducer which has been experimentally verified and installed at the end one (near end) of cable. The standard PD pulse calibrator with the charge of 200 pC was used to investigate the PD location at various position along the cable with total length is 37.925 m. The PD location method, time domain reflectometry (TDR) is used to locate the PD defect along the cable, which essentially based on the f travelling wave theory. From the experimental results of PD location, the highest error of PD location by time domain reflectometry method is 0.859 % at PD defect point (x) of 21.41 m. From this experiment, the proposed technique can be applied to further practical application and research related to PD location. - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Implementation of a Rogowski's coil for partial discharge detection(2017-01-30); This paper presents the implementation of a Rogowski's coil for a special purpose on partial discharge detection. A numerical integrator and a filter are used with the Rogowski's coil to calculate partial discharge current and apparent charge. Implementation of the Rogowski's coil in a laboratory, such as a unit step response, linearity of the measurement, and partial discharge detection, is performed. It is found that the partial discharge current and the apparent charge which are detected by the Rogowski's coil are agreed well with the measurement from the conventional method. - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Applications of a high frequency current transformer and air-core inductive devices for detecting a partial discharge location in a cable(2020-01-01); This paper presents applications of partial discharge sensing devices for detecting a partial discharge location in a cable. Three devices are under investigated. The first type is a high frequency current transformer (HFCT), while other two types are air core inductive devices with different configuration. The high frequency current transformer is constructed from a ferromagnetic material core, and the winding conductor is in a single compensation form. The first air core inductive device is wound in a single compensation pattern, and uses the return winding in the form of a copper sheet. The second air core inductive device, differently, is in a counter wound compensation pattern. In experiments, a partial discharge sensing device is installed at one end of the cable. The standard pulse calibrator is employed to inject partial discharge pulses at the designated locations along the cable. The Time Domain Reflectometry technique (TDR), which is based on the travelling wave theory, is employed in calculating the partial discharge locations. It is found that these three current transducers can detect the partial discharge pulses, and with the algorithm, which is developed using the Time Domain Reflectometry, the partial discharge location along the cable can be identified accurately. - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Analysis of power system event using synchronized PMUs in Thailand power network(2007-12-01); ; - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Analysis of frequency converters for PD test(2017-10-27); ; Potivejkul, SiriwatThis paper presents the analysis of an AC-AC converter used in partial discharge test. In this paper, the analysis of the frequency converter is separated into two parts. Firstly, the converter models are simulated by a circuit simulation program for comparing noise signals generated by the 2-level SFC and 5-level SFC. The frequency of the converter was set to be 200 Hz. With the help of the simulator, the approach for noise mitigation with filter application is designed and applied to the PD test system. In the second part, the developed static frequency converters are used in the partial discharge tests for confirming the simulation results. From all simulated and experimental results, it can be concluded that the 5-level SFC has high efficiency, low generated noise signal, and also very attractive for using in partial discharge test.