Yutthagowith, Peerawut
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Yutthagowith, Peerawut
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Yutthagowith, P.
Yutthagowith, Pearawut
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peerawut.yu@kmitl.ac.th
14 results
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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, Improved Least-Square Prony Analysis Technique for Parameter Evaluation of Lightning ImpulseVoltage and Current(2016-02-01); This paper represents a fast curve-fitting technique for evaluation of either lightning impulse voltage or the current base curve. The technique based on least-square Prony analysis employs the double integration of the recorded waveform for waveform evaluation. The undesirable effect of noise exiting in Prony analysis technique is mitigated. The base curve formula is written in the complex form of the double exponential function. A decomposition technique is utilized for determination of the base curves of full lightning impulse voltages with oscillations and of lightning impulse currents. To verify the performance of the proposed method, the base curves reconstituted from the developed method were compared with the curves reconstructed from a nonlinear least-square regression prescribed in the standard. The execution time of the proposed method is much shorter than that of the conventional method because it does not need the iteration process. With noise immunity characteristics and avoidance of recorded waveform distortion, the results from the proposed technique based on the normal implementation are remarkably accurate. The results of this study indicated that the proposed method is the powerful one to apply for lightning impulse voltage and current base curve evaluation. - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Partial discharge classification on high voltage equipment with K-means(2006-01-01); ; This document proposes a statistical classification model using k-means cluster analysis to classify partial discharge (PD) patterns into four categories listed as corona at high voltage side in air, corona at low voltage side in air, surface in air, and internal discharge. The independent variables in this k-means cluster analysis model are skewness, kurtosis, asymmetry, and cross correlation following the φ - q - n PD patterns obtained from the fingerprint analysis which is a digital signal processing technique for PD measurement. The experiments were set to simulate all four PD patterns to obtain statistical parameters into 10 independent variables from the fingerprint analysis. This document recommends using 8 final clusters instead of using 4 final clusters to achieve the accuracy of using this k-means cluster approach to 100 percent. © 2006 IEEE. - Some of the metrics are blocked by yourconsent settings
Item type:Publication, The effect of convexity of lightning impulse voltage waveforms on accuracy of HV measuring systems(2006-01-01); ; ; Phoomvuthisarn, S.This paper presents the effect of convexity of lightning impulse voltage waveforms on accuracy of HV measuring systems. The effects of different three convexities on wave front are analyzed by simulation tests with some standard waveforms. The simulation tests have two aspects. First one is consideration in frequency domain by using FFT with standard waveforms and transfer function of measuring system and second one is consideration in time domain by using time convolution method or Duhamel's integration method for computing waveform outputs standard testing waveforms and unit step responses of the sample measuring systems. The standard waveforms under investigations are full lightning impulse voltage waveforms, tail-chopped of lightning impulse voltage waveforms, front-chopped of lightning impulse voltage waveforms according to IEC standards 60060-2. This paper considers two samples of different types of the measuring systems. The results show that the convexity has effect on accuracy of measuring systems. © 2006 IEEE. - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Equivalent circuit approximation of transformer insulation by using PDC measurement(2008-10-06); ; Thongkaemkaew, K.This paper represents the insulation model of 3φ, 50 MVA, 132.8/13.8 kV power transformer. This model is developed from the polarization and depolarization current measurement (PDC). The insulation modeling consists of a parallel circuit among C<inf>50</inf> <inf>Hz</inf>, R<inf>0</inf>, R <inf>1</inf> and C<inf>1</inf> in series, R<inf>2</inf> and C<inf>2</inf> in series, R<inf>3</inf> and C<inf>3</inf> in series, and R<inf>4</inf> and C <inf>4</inf> in series. C<inf>50</inf> <inf>Hz</inf> is obtained from the conventional measurement method; whereas, the applied step voltage and the sum of PDC are calculated for R<inf>0</inf>. The individual elements (R<inf>1</inf> and C<inf>1</inf>) are determined from fitting technique employing MATLAB program. From experimental results of the tested transformer, the example of insulation model for Transformer No. 1 (T1) is created with C<inf>50</inf> <inf>Hz</inf> of 3.643 nF, R<inf>0</inf> of 334.8 GΩ. The values of R <inf>1</inf>-R<inf>4</inf> are 86.52, 110.5, 669.5 and 271.0 GΩ respectively; while, the values of C<inf>1</inf>-C<inf>4</inf> are 37.62, 6.047, 0.101 and 0.013 nF respectively. The proposed model is validated by calculating dissipation factor and measuring dissipation factor. The results show that the proposed model and experimental validation are good agreement with each others. © 2008 IEEE. - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Pattern classification of partial discharge in high voltage equipment by regression analysis(2008-10-06); - Some of the metrics are blocked by yourconsent settings
Item type:Publication, The study of disc monopole antenna for partial discharge measurement(2007-12-01); ; Aunchaleevarapan, KraisionThis paper presents the study of disc monopole antenna for partial discharge measurement. The antenna was studied with computer program and tested. Then it was used for partial discharge measurement of the artificial partial discharge models, corona discharge, surface discharge, and internal discharge. The partial discharge tested results obtained from the designed antenna are relatively similar the tested results obtained from the standard antenna. The tested results show that the designed disc monopole antenna prototype has the good characteristics to measure partial discharge phenomena. It is still improving for high efficiency. © 2007 RPS. - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Effective circuit parameter determination in lightning impulse voltage tests of air core inductors(2016-01-01); - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Dielectric diagnosis of 24kV XLPE cable using polarization and depolarization current, conventional partial discharge measurements and high frequency current measurement(2016-01-01); Medium voltage power cables are an important element of electric power distribution. Most of cable failures occurring in XLPE insulation and cable accessories are due to insulation failure. This research work represents the dielectric investigation of 12/20(24) kV XLPE power cables including cable joints by using polarization and depolarization current (PDC) measurement, conventional partial discharge measurement according to IEC 60270, and high frequency current measurement measured by high frequency current transformer (HFCT). In this research work, six case studies, case 1: PE sheath damaged, case 2: semi-conducting layer damaged, case 3: void defect in extruded cable, case 4: void defect in extruded cable at cable joint, case 5: semiconductive contaminant at cable joint, and case 6: conductive contaminant at cable joint, were investigated. The test results showed that two basic properties, polarization and depolarization current, of cable insulation can be utilized for classification of cables with joint problems. The defects in extruded cable and cable joint can be identified by the PDC shapes. However, to clarify the problems occurring at the cables by conventional PD measurement and HFCT measurement was performed. Moreover, it was found that the sensitivity of HFCT was clearly lower than conventional tool. - 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.