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Analysis of power quality issue in arc furnace capacitor bank system
(2017-01-30)
Sreewirote, B.
;
Ngaopitakkul, A.
In large furnace industry in Thailand, power factor has become a concerned issue due to electric utility department that charges extra money from factory causing low power factor. Many factories have been using capacitor bank to compensate reactive power, thus, increasing power factor in factory. With the capacitor bank, power quality in terms of harmonic current has become problem due to the switching transient that magnifies current harmonics and causes severe damage to capacitor bank and other nearby sensitive equipment. This paper aims to study power quality issue in terms of harmonics in steel furnace factory and its effect when switching capacitor bank into system. The study is done by using data from furnace plant in Phetchaburi province, Thailand as case study. The result reveals that after switching capacitor bank, harmonics have been significantly increased, thus, protection scheme must be implemented to ensure safety and reliability of the plant.
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Investigation of skew effect on the behavior and performance of grid connected induction generators
(2017-01-30)
Sawetsakulanond, B.
;
Kinnares, V.
This paper proposes the investigation of skew effect on the behavior and performance of three phase, 2.2 kW, 220/380 V, Δ / Y connected, 1420 rpm, 4 poles grid connected induction generators with skewed squirrel cage rotor for supplying electric power to utility grid. Skewed rotor with angle of 0°, 5° and 10° for grid connected induction generators are employed. Analysis and comparative study on operating of induction generators under transient and steady state conditions have been performed. Research results will be guidelines for an application of wind induction generator for electricity generation.
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Fast, simple, accurate fundamental frequency estimation
(2016-01-01)
Yutthagowith, P.
;
Kunakorn, A.
This paper presents a simple, fast, accurate fundamental frequency estimation method with good resistance to harmonics and noise. In the proposed method named the accumulated sum method (ASM), a new data sample of a measured signal is constructed using the summation of the samples in the original sampling data. The effects of harmonics and noise are mitigated by the proposed algorithm. Performance comparison of the proposed method, the method based on the discrete Fourier, and the accurate method named shifting window average method (SWAM) is demonstrated by using simulated signals with varied fundamental frequency from 45 Hz to 65 Hz and with additive harmonics and noise. In the simulation, the sampling frequency and the number of samples is fixed to 5000 samples/s and 100, respectively. From the simulation results, the proposed method exhibits good immunity to harmonics and noise. Due to its low required processing effort and high precision, this method is a good candidate for online frequency estimation in the presence of harmonics and noise signals.
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Energy savings analysis and harmonics reduction for the electronic ballast of T5 fluorescent lamp in a building's lighting system
(2015-06-15)
Chiradeja, P.
;
Ngaopitakkul, A.
;
Jettanasen, C.
Lighting is one of the major energy end uses, which accounts for approximately 20-30% of electricity consumption in buildings. In fact, the fluorescent lamp is the most employed lamp in a lighting system for both inside and outside the building. The ballast is one of the major components of fluorescent lamps; it exists commercially as an electromagnetic ballast, a low loss ballast and an electronic ballast. To reduce energy consumption in a lighting system, the electronic ballast has already been introduced for profit in terms of its peak demand reduction and energy conservation in the building. However, when the electronic ballast functions, harmonics will be generated. Hence, this paper investigates energy savings and the generation of harmonics when using a fluorescent T5 lamp with electronic ballast in a building. The efficiency indices in terms of illumination, energy savings, and harmonics are also evaluated and compared with the fluorescent T8 lamp operating with a low watt loss electromagnetic ballast, which is also widely used. The obtained results are useful for the design and decision to install a fluorescent T5 lamp with electronic ballast in building lighting system to conserve energy and/or reduce energy consumption for the future of the country.
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Study of harmonics issued from electronic ballast used to reduce energy consumption in Thailand's building
(2014-01-01)
Jettanasen, C.
;
Ngaopitakkul, A.
In 2009, the T5 fluorescent tube lamp with electronic ballast was launched by the Electricity Generating Authority of Thailand (EGAT) in order to reduce energy consumption in building. The ballast is one of major components of fluorescent lamp. The installation of T5 fluorescent lamp in building has the effect of harmonics. This paper investigated the impact of harmonics from various electronic ballasts existing commercially, and compared with conventional ballast. The obtained results show that the T5 fluorescent tube lamp functioning with electronic ballast is a promising candidate to replace the T8 fluorescent tube lamp with electromagnetic and low watt loss ballast in building. © 2014 IEEE.
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The result analysis of the power loss 3-phase induction motor with PWM inverter supply
(2005-01-01)
Thammarat, C.
;
Tadsuan, S.
;
Suechoey, B.
;
Bunjongjit, S.
The purpose of this research is to study the power loss generating of the PWM inverter and the 1 HP 380V 3-phase squirrel cage induction motor. In the test procedure was performed by varying fundamental frequency in the range 25-50Hz and at constant 1.5 kHz - PWM Inverter switching frequency, as a source to the 3-phase 380V squirrel cage induction motor in star connection with 5.1 N.m constant torque load. The test analysis was to record the input/output voltage/current waveforms by using YOKOGAWA DL1640 Storage Oscilloscope. Then, using the function FFT program was to determine the variety parameters at each harmonic from those waveforms. The total power loss and efficiency a were calculated by those parameters. The results show the input power is minimum at 25 Hz fundamental frequency and maximum at 50 Hz. But the efficiency is minimum at 25 Hz fundamental frequency and maximum at 50 Hz. The minimum motor power loss is at 35-40Hz fundamental frequency and the maximum inverter power loss at 81-85% efficiency is around 25-50 Hz fundamental frequency. And also, this is the useful information in designed inverter process to extend the motor' life due to the overheat from power loss.
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Analysis of harmonic for 12-pulse converter under unbalanced voltage operation due to lightning related voltage sags and short interruption
(2001-12-01)
Boonseng, C.
;
Kinnares, V.
This paper presents a summary of power quality related concerns associated with the applications of 12-pulse converter with dc motor drives in the industrial plants. These concerns include power system harmonic and harmonic distortion under unbalance voltage condition during voltage sags occurrence. The definition proposed focuses on system faults due to lightning. The voltage unbalance causes large unbalance source currents resulting in excessive input current and high distortion. The percentage of total harmonic distortion of input current (THD<inf>i</inf>) increased approximately 47% at 6 per unit of normal peak current. The measurement and analysis of such events has been performed. Finally, the new phase-angle jump concept based on measured techniques is introduced.
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Nonsinusoidal voltage source using the technique of brushless synchronous reluctance generator
(2000-01-01)
Lumyong, Pichit
;
Chat-Uthai, Chaiwut
This paper presents a preliminary study of the technique of Brushless ,synchronous Reluctance Generator (BSRG) combined with the utility power supply for generating a nonsinusoidal three-phase voltage waveform. The PAM techniques have still faced a few problem of how to control the amplitude and the kth order harmonic voltage wave. The harmonic generator using BSRG technique can be used as source and sink power characteristics in any kind of load in the power system. Therefore, the frequency and amplitude of the waveform obtained from this harmonic generator can be independently controlled in order to use, for a study of how the harmonics affect three-phase induction motors or transformers. Finally, the nonsinusoidal voltage waveforms of the fundamental with the 3rd, 5th, 7th and 10th order harmonics at various voltage distortion factors (KDF) obtained from BSRG technique are illustrated and discussed.
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Harmonic analysis of corona discharge ozone generator using brush electrode configuration
(2000-01-01)
Boonseng, C.
;
Kinnares, V.
;
Apriratikul, P.
This paper describes a new method of ozone generation particularly suited to use in water treatment. The authors present harmonic analysis and the ozone concentration generated by a new type of ozone generation. Relative harmonic distortions in line input have been investigated experimentally. The experimental results were obtained using a concentric cylinder with brush electrode separated by a glass tube. This configuration can avoid breakdown. Essentially AC high voltage is derived from a high voltage transformer, which is controlled by a flyback converter. The ozone generator can produce 64 ppm ozone at 15 kV output and switching frequency approximately 20 kHz. Finally, the effects of corona discharge power on the corona surrounding temperature and its relationship with ozone concentration have also been investigated.

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