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Determination of water in transformer by water solubility and percent moisture by dry weight in comparison with ppm water value for justification transformer maintenance
(2020-10-25)
Wannapring, E.
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Sirisithichote, T.
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Pattanadech, N.
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Leelajindakrairerk, M.
The measure of water content is to find water content in transformers. There are many ways that water can occur in the transformers, such as residual moisture in the paper insulation and oils during the manufacturing process, generating from the degradation of transformer paper insulation and oil, ingression into the transformer, etc. The water in the transformer resides in liquid insulation approximately 1% and in the solid paper insulation of roughly 99%. The status of water in oil and water in paper insulation is not stable; water in paper insulation moves into transformer oil and vice versa, depending on loads and temperature. Both waters in oil and water in paper insulation reduce the insulation property of the transformer. This paper aims to present the observations of total water content in the transformer (water in oil and water in paper insulation) compared to the PPM value directly from laboratory testing to understand the severity and manage proper transformer maintenance decisions.
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Analysis of harmonics in indoor Lighting System with LED and fluorescent luminaire
(2017-07-25)
Bunjongjit, S.
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Ngaopitakkul, A.
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Leelajindakrairerk, M.
Lighting system is an important part in everyday life. Today, lighting technology has been developing in many aspects. Technology such as Light Emitting Diode (LED) luminaire has been applied to indoor lighting system to replace conventional luminaire. LED lamps have many advantages such as less energy consumption, long life cycle and environmental friendly issue due to without toxic component. However, installation cost is main concern for investor regarding changing conventional lamp toward LED. So, the lighting system in some building are consist of both conventional and LED luminaires. In such a case the power quality must be taken into consideration. This paper aims to study power quality problem in term of harmonics generated by lighting system consisting of both fluorescent and LED luminaires. The obtained result can be used to design filter circuit for harmonic reduction in lighting system.
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Design and development of solar water pump
(2017-01-30)
Sreewirote, B.
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Leelajindakrairerk, M.
There are many agriculturists who have cultivated in area far away from water source in Thailand, thus, farmer needs to install water-pumping system to irrigate their farm area. Solar water pump system is one of system that is applied photovoltaic panel for water pump as power source. In daytime, photovoltaic panel can generate power and storage in battery to be used later without concerning over weather. Another benefit from system is to reduce energy cost and environmental impact compared to traditional diesel water pump. Therefore, this paper aims to design and develop solar water pump with charger controller for batteries. Performance of solar water pump system in terms of temperature, voltage, and current have been evaluating in this study.
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Study of characteristics for simultaneous faults in distribution underground cable using DWT
(2011-12-01)
Ngaopitakkul, A.
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Pothisarn, C.
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Leelajindakrairerk, M.
In the literature for fault detection, most of research works have never been mentioned about effects of simultaneous faults. This paper presents behavior of characteristics for simultaneous fault signals in an electrical distribution underground cable using wavelet transform. The fault signal is simulated using ATP/EMTP, and the behavior analysis of signals is performed using discrete wavelet transform (DWT). The DWT is used to detect the high frequency components. The results obtained from the analysis will be useful in the development of a detect fault scheme for electrical distribution underground cable in the future due to an effect of the other fault that occurs at the other side of the system; this leads to the malfunction of the protective relays. © 2011 IEEE.
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Pattern classification of partial discharge in high voltage equipment by regression analysis
(2008-10-06)
Ludpa, S.
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Pattanadech, N.
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Leelajindakrairerk, M.
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Yutthagowith, P.
This paper introduces a statistical classification in regression model to classify partial discharge (PD) patterns into four categories in corona: high voltage side in air, corona at low voltage side in air, surface in air, and internal discharge. There are nine independent variables from fingerprint analysis which mainly are skewness, kurtosis, asymmetry and cross correlation following φ - q - n PD patterns. The variable independent data are divided into two group: the forms for training the model and the pattern for test the model. The created algorithm investigates the best of parameter group from all of independence variables for creating the regression model. In this work, the group of five best parameters for classification are selected. The results show, that only five parameters in the model has a good performance to classify PD pattern with the classification accuracy of 100%. © 2008 IEEE.
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Design optimization of wind power planning for a country of low-medium wind speed profile
(2007-12-01)
Chompoo-inwai, Chai
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Banjongjit, S.
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Leelajindakrairerk, M.
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Faungfoo, P.
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Lee, Wei Jen
the emerging energy crisis results from a high-price of crude-oil has drawn attention about renewable energy all over the world. Thailand is a developing country located at the heart of Southeast Asia with about 66 million of population as of 2006. The ESI structure under the government of Thailand has been managed by the Electricity Generating Authority of Thailand (EGAT), Metropolitan Electricity Authority (MEA), and Provincial Electricity Authority (PEA) for almost 50 years. According to the 2004 Power Development Plan (PDP), the country would have generation reserve at a marginal of 15 percent. Due to the rapid economic growth and difficulty in building new centralized generating facilities, this has the potential to create a security issue of electricity energy shortage and may develop a severe system blackout. Renewable energy issues have been widely discussed and debated over the country. Although solar energy is the most prominent renewable energy source due to the appropriated geographic of Thailand, it still considered as a low-density energy source which requires a large area of installation. Therefore, for the long term investment, wind power seem to be a good candidacy since it is quick to get permission, need no fuel cost, and environmental friendly. Therefore, this paper investigates the impact of penetration level of wind powered generation to be integrated into Thailand system. System stability has been observed in various system configurations change due to different control strategies of wind farms. The economics analysis of wind farm investment has been also considered. © 2007 IEEE.
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Design and construction of a Rogowski's coil with compensated RC integrators for measuring impulse current
(2007-12-01)
Yutthagowith, P.
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Pattanadech, N.
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Kunakorn, A.
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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.
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Single phase and three phase PWM inverter supply optimum selection for core losses reduction
(2006-12-01)
Suechoey, B.
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Thammarat, C.
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Tadsuan, S.
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Leelajindakrairerk, M.
This paper presents the comparison of core loss with 1-phase bipolar inverter supply to 3-phase inverter supply (2- line). In the experiment, by using 0.30 mm.-thick grain oriented magnetic steel(M5) and by setting equal maximum magnetic density for each test procedure, with 0.3, 0.6, 0.9- modulation index and 1, 2, 3, 4, 5 kHz.- inverter switching frequency, the voltage and current are saved to data file. By using the function FFT program to analyze the data file, the test results shown that the core loss by 3-phase inverter supply (2-line) is less than that by 1-phase bipolar inverter supply, so this study is useful for selecting the PWM inverter to get the lower core loss.
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An analysis of temperature and pressure on loading oil-immersed distribution transformer
(2005-01-01)
Suechoey, B.
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Tadsuan, S.
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Thammarat, C.
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Leelajindakrairerk, M.
This paper presents the analysis of temperature and pressure on loading oil-immersed distribution transformer at rated load. The tested transformer is sealed type oil-immersed distribution transformer of 400 kVA 3ph 50Hz 22000-400/230V Dyn 11. The results will be useful for developing the design, correction, protection, load specification and temperature estimation of transformer with efficiency, in order to improve better cooling and transformer tank's strengthen. And these will increase transformer aging and stability of distribution system.

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