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Application of A PEEC Method in Backflashover Simulation of HV Transmission Lines in Thailand
(2019-09-01)
Yutthagowith, P.
;
Sirachansawang, P.
For high voltage transmission lines, direct lightning strikes a tower shielding wire can cause the backflashover phenomena. In this paper, the partial element equivalent circuit (PEEC) method was used as a simulation tool for study of these phenomena of typical 230-kV transmission lines. The discharge process on string insulators is represented by the disruptive effect (DE) method. The lightning current ranges with various tower grounding impedances, causing backflashover in the 230 kV double circuit line with two grounded shielding wires have been investigated in detail. Preventing 95% of lightning strikes causing the backflashover, the proper grounding impedance can be determined.
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Design of Counterpoise Grounding Electrodes Encased with Low Resistivity Material for Transmission Towers
(2019-05-15)
Sirachansawang, P.
;
Horchue, T.
;
Yutthagowith, P.
This paper presents design of counterpoise electrodes encased with earthing enhancing compounds or more effective grounding (MEG) for transmission towers. Approach is based on a full-wave electromagnetic analysis. For counterpoise analysis, the partial element equivalent circuit (PEEC) is used. In this paper, we use lightning parameters from IEC 62305 as reference. For normal case, the soil ionization and frequency dependent parameters are ignored. In cases high ground resistivity more than 1000 ohm-meter, grounding of long counterpoise makes the capacitive result, this make electrode impedance lower than resistance. The impulse impedance of the four-leg and eight-leg counterpoise electrode in area which is high ground resistivity of 5000 ohm-meter, grounding impedance cannot be achieved because of the result of effective length. The MEG is encased with the eight-leg grounding electrode impedance can be accomplished.
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A partial discharge testing system based on a 5-level converter with different control signals
(2018-11-01)
Yomkaew, N.
;
Marukatat, N.
;
Yutthagowith, P.
In this paper, analyses of a partial discharge (PD) testing systems using a voltage source from a 5-level converter with different control signals are presented. The low voltage source with 200 Hz of the test system is generated using the 5-level converter. The converter connected to a high voltage transformer, a partial discharge detection. The LC-filter type is set for the test system. The efficiency of voltage source from the 5-level converter with different control signal topologies, i.e. 5-level square wave, 5-level quasi-square wave, and 5-level sinusoidal pulse width modulation (SPWM) with modulation index (m<inf>a</inf>) of 1.0. The effect of the topologies to partial discharge test system is presented and compared in cases of the voltage difference, total harmonic distortion (THD<inf>v</inf>) of the output voltage, and the background noises in the partial discharge testing system with no-load and load test with a potential transformer (PT). It is found that the 5-level sinusoidal pulse width modulation (SPWM) with modulation index 1.0 provides the best performance in cases of the voltage difference and THD<inf>v</inf> of below 5%, and the background noise of below 2.5 pC.
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Development of a low-pass filter for partial discharge testing system with the power frequency converter
(2018-11-01)
Prombud, T.
;
Kitcharoen, P.
;
Yutthagowith, P.
The development of a low-pass filter for partial discharge test system that based on a power frequency converter is presented in this paper. The PD testing system is composed a 200-Hz power frequency converter and the designed filter connected with a high-voltage test transformer and a conventional partial discharge detection system. It is found that the power frequency converter acting as the low-voltage source always provides the high noise level with effecting to the background noise occur in the partial discharge test. Sometimes noise level is higher than the acceptable level of the PD tests in some high-voltage equipment such as potential transformers, distribution transformer, and so on. In this paper, the performances of the filters with different designs are studied and compared the result in terms of the output voltage difference (RMS, voltage , and ,peak,voltage 2), total harmonic distortion of the output high voltages value (THD<inf>v</inf>), and value of background noises as occur in the partial discharge test. The low-voltage source based on uni-polar pulse width modulation (PWM) topology was employed in the PD testing system. From the experimental results, the designed filter shows the promising performances with low levels of the background noise, THD<inf>v</inf>, and voltage difference. The experimental results show that the background noise is lower than 2.0 pC, the voltage difference and THD<inf>v</inf> are less than 5%. In addition, the designed filter has been tested in the partial test of a real potential transformer successfully.
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Applications of Ozone for Recycling of Wastewater from Biogas Production for Electricity Generation
(2018-08-21)
Tantirungruang, W.
;
Chancharoensook, P.
;
Yutthagowith, P.
This paper presents applications of ozone to recycle the wastewater from the biogas production process for electricity generation. The ozone could be generated by using electric field between polarized electrodes. In comparative experiments, three tanks were used for biogas fermentation using anaerobic microorganisms. We designed three different experimental settings as follows: 1) The one using only fresh wastewater from ethanol production process. 2) The one using recycled wastewater with ozonation. 3) The one using recycled wastewater without ozonation. The experimental results indicated that ozone could help improving the biogas production to 2.1 liters/day per 1 liter of recycled wastewater. The methane and carbon dioxide concentrations were 66. 8% and 38. 5%, respectively.
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Development of a resonant frequency converter for partial discharge tests on potential transformers
(2018-06-08)
Yutthagowith, P.
;
Prombud, T.
;
Leelachariyakul, B.
In this paper, the development of a partial discharge testing system based on a resonant frequency converter for potential transformers (PTs) is presented. The system is composed of a power low-voltage variable frequency converter connected with a frequency tuning circuit, a high-voltage testing transformer, and a conventional partial discharge detection system. The performances of the developed system in comparison with the conventional PWM frequency converter were investigated terms of the quality of the output voltage from the high-voltage testing transformer, i.e. the voltage difference (peak voltage/square root of 2 and rms voltage), total harmonic distortion of the output high voltages (THDv), and background noises in the partial discharge test. It is found that the developed system based on the resonant frequency converter provides the better performances (in terms of the output voltage from a testing transformer, the voltage difference, THDv, and background noise) than those of the PWM converter. The voltage difference and THDv are lower than 2%, and the background noise is less than 2.5 pC. In addition, the developed system has been used for the real partial test on a potential transformer in the distribution system successfully. The developed inverter is an attractive choice in the PD tests of potential transformers.
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Development of a partial discharge testing system for potential transformers
(2018-04-27)
Prombud, T.
;
Kitcharoen, P.
;
Yutthagowith, P.
In this paper, the development of a partial discharge testing system for potential transformers (PTs) is presented. The system is composed of a low-voltage and 200-Hz power frequency converter connected with a low pass filter, a high-voltage transformer, and a conventional partial discharge detection system. The performances of the converter with three generated waveform, i.e. square wave, quasi-square wave, and unipolar pulse width modulation (PWM) are compared in terms of the DC charging voltage, the voltage difference (peak voltage/square root of 2 and rms voltage), total harmonic distortion of the output high voltage (THDv), and background noises in the partial discharge test. It is found that the unipolar PWM frequency converter provides the best performances in terms of the voltage difference, THDv, and background noise. The voltage difference and THDv are lower than 5%, and the background noise is less than 2.5 pC. In addition, the developed system has been used for the real partial test on a potential transformer in the distribution system successfully.
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Analyses of rogowski coils for partial discharge measurement
(2017-10-27)
Chonpathomphikunloed, W.
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Paophan, B.
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Kunakorn, A.
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Yutthagowith, P.
;
Leelachindakrairerk, M.
This paper presents analyses of toroidal air core Rogowski coils (RCs) with self-integrator for partial discharge (PD) measurement. The RC is the electromagnetic transfer device for measuring fast current pulse. The RC has linear characteristic and no saturation due to the air core. There are four configurations of the RCs in the consideration in this paper. From each designed RC, inductance and turn of each RC was determined almost the same values but different configurations. To analyses of the developed RCs, those RCs were employed to measure partial discharge current with various artificial charge levels from 10 pC to 50 pC. Also, comparison of the PD signals measured by the developed RCs and low inductive shunt resistor was carried out. From the experimental results, the best developed RC has the highest sensitivity or lowest background noise. It composes of two copper winding wound in the different directions. The first winding is wound around the toroidal air core and the other winding is wound with the opposite direction of the first winding. The both winding are crossed at the inner of the toroidal core. This RC also has wind frequency bandwidth for PD detection. The developed RC is an attractive sensor in partial discharge measurement.
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Implementation of a Rogowski's coil for partial discharge detection
(2017-01-30)
Paophan, B.
;
Kunakorn, A.
;
Yutthagowith, P.
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.
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A modified pi-shaped circuit-based model of grounding electrodes
(2016-12-19)
Yutthagowith, P.
This paper proposes a modified pi-shaped circuitbased model of grounding electrodes. The validity length and soil resistivity of the proposed model are from 2 m to 40 m and from 50 m to 2000 m, respectively. The equivalent circuits in the form of pi configuration are modeled by lumped parameters composing of inductance, resistances, and capacitances. The voltage responses to the standard lightning currents of grounding electrodes either calculated by an electromagnetic model or from experiments are matched with those of the proposed model. A curve fitting technique is employed to extract parameters of the equivalent circuit. The satisfactory agreements have been observed. The simple soil ionization model can readily be adapted in the proposed model. The proposed model is very useful in implementation with a circuit simulator such as EMTP, Pspice, and so on. The proposed circuit model can be adapted for being the models for development and design of the grounding system for lightning protection system in transmission and distribution systems in an effective way.

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