Kunakorn, Anantawat
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Kunakorn, Anantawat
Alternative Name
Kunakorn, A.
Kunakorn, Anatawat
Main Affiliation
Email
anantawat.ku@kmitl.ac.th
16 results
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Item type:Publication, Polarization and depolarization current characteristics of thermally stressed stator bars(2019-07-01); - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Computer aided-program for validation of measuring system from unit step response by time convolution method(2005-01-01); ; ; Phoomvuthisarn, S.This paper presents the design and development of the computer algorithm based on LabVIEW for verification of a high voltage measuring system. The algorithm consists of two parts. The first part is a program for calculating the parameters of unit step responses which are verified an ability of the measuring system by a comparison with the values given in IEC 60060-2. The second part is a program for calculating the output voltage waveform by time convolutions between standard testing waveforms and unit step responses. The standard waveforms under investigation are full lightning impulse voltage waveforms, tail-chopped lightning impulse voltage waveforms, front-chopped lightning impulse voltage waveforms and steep-front voltage waveforms according to IEC standards 60060-2 and 61211. This paper considers two different types of the measuring systems, with a resistive voltage divider and a damped capacitive voltage divider for testings. The results show that the algorithm proposed in this paper is practicable, and should be a useful tool for impulse voltage measurements in a standard high voltage laboratory. - Some of the metrics are blocked by yourconsent settings
Item type:Publication, The Study of Polarization and Depolarization Current Measurements on Service-Aged 22 kV XLPE Underground Cables with Presence of Water Trees(2022-01-01); ; This paper represents the condition assessment of service-aged 22 kV XLPE insulated underground cables. From the investigation, the water trees were detected in the insulation layer. The visual inspection of underground cables reveals the presence of copper carbonate contaminated on the copper tape layer. Some underground cables have the discontinuity of the copper tape layer. To evaluate the insulation condition of the underground cables, the polarization and depolarization current (PDC) measurements were performed on both the service-aged and the new (or unused) cables. The underground cables to experiment with the length of insulation screen equal to 1 m were prepared. In this research, the PDC measurements were performed on different aspects, i.e., the testing voltages (600 V, 800 V, and 1000 V), the testing positions, the effect of the discontinuity of the copper tape layer which occurred during service, the influence of the presence of copper carbonate, and the influence of water trees in XLPE cables. The dielectric response of the underground cables by using polarization and depolarization current measurements can diagnose the problems in service-aged underground cables, but this paper needs more test data for accurate interpretation. - 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, Dielectric response analysis for cable joint problems in medium voltage underground cable system(2020-01-01); This paper represents the investigation of dielectric response analysis of a cable system composed of a medium voltage XLPE underground cable, a heat-shrink cable joint and a heat-shrink cable termination. A 12/20(24) kV single core XLPE underground cable with the nominal cross-section area of 240 mm<sup>2</sup>, three pieces of 22 kV cable joints, and eight pieces of 22 kV cable termination were prepared for the experiment. Then, polarization and depolarization current (PDCs) measurement were performed. The experiments were divided into two parts. The first part was composed series of three tests, A — C, and the second part consisted series of two tests, D — E, as follows: Test A examined dielectric response of a 6 m healthy XLPE underground cable, Test B examined dielectric response of a 6 m healthy XLPE underground cable with two healthy cable terminations, Test C examined dielectric response of a two of 3 m healthy XLPE underground cable with healthy cable terminations connected by a healthy cable joint, Test D used the test object similarly as case C but the cable joint was contaminated with copper particles, and Test E used the test object similarly as case C but the cable joint was contaminated with tiny pieces of water blocking. From the experiment, the PDCs and the derived dielectric parameters such as geometrical capacitance, insulation resistance, polarization index, depolarization index, charge difference curve and charge ratio curve were analyzed. The PDCs and the derived parameters were found different for each case of study as details in this paper. Besides, the charge ratio proposed by authors is a valuable parameter for the diagnosis of insulation system of high voltage equipment. - Some of the metrics are blocked by yourconsent settings
Item type:Publication, A CASE STUDY ON DIELECTRIC RESPONSE MEASUREMENT OF HIGH VOLTAGE GENERATOR INSULATION SYSTEMS(2023-01-01); - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Study of asymmetrical leakage currents of metal oxide surge arrester due to multiple current impulses(2020-09-13); This paper presents the study of asymmetrical leakage current of metal oxide surge arrester (SA) after being tested with multiple current impulses. The study is made using 2 SAs specimens of 21 kV rated voltage, 5 kA nominal discharge current. The experiment is divided into 4 steps; 10 shots of positive discharge current impulses, reference voltage measurement, 5 shots of negative discharge current impulses and reference voltage measurement. Initial conditions of the SAs are assessed prior to the testing: temperature measurement, 1 mA reference voltage and resistive leakage current at rated voltage. Then, both specimens are applied current lightning impulses at 200% of rated discharge current (10 kA) and the temperature is measured after. The lightning current impulse is 8/20 µs waveform and the duration between each impulse is 10s. Prior to the application of multiple current impulses, the difference of resistive current peak amplitude of specimen 1 and 2 were 3% and 0.95% respectively. Following positive current lightning impulses, the value changed to be 71.245% and 72.75% respectively. The specimens were then left to cool down in the room temperature for 1 day. After application of negative current lighting impulses, difference of resistive leakage current of specimen 2 changed to be 1.99%, and specimen 1 broke down after 2 impulses. Asymmetrical leakage current phenomena caused by the impulse current may negatively affect the breakdown characteristic of the SA which should be relevant with the collected charge inside the SA material, however, the opposite polarity of the applied impulse currents may eliminate such problem. - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Design and construction of a Rogowski's coil with compensated RC integrators for measuring impulse current(2007-12-01); ; ; Leelajindakrairerk, M.This paper presents design and construction of an impulse current measuring system used in residual voltage tests for surge arresters. The measuring system is composed of a Rogowski's coil and an RC integrator with a compensation circuit. The simulation and experimental results show that the system gives better performances compared with the conventional method. © 2007 RPS. - 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);