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The effects of multi-distributed generator on distribution system reliability
(2018-06-08)
Ngaopitakkul, A.
;
Jettanasen, C.
The paper investigates on the effects of multi- distributed generators (multi-DG) integrated to distribution system in terms of reliability indices. The distributed generators (DGs) under this study are solar photovoltaic (PV) connected to a 22 kV distribution system. In addition, it presents to determine the system average interruption frequency index (SAIFI), the system average interruption duration index (SAIDI) and outage cost as reliability indices by comparing the SAIFI, SAIDI and outage cost (ECOST) of the cases that multi-DG is connected to a distribution system. The reliability indices will be calculated using data obtaining from simulation and analysis of power distribution system model created in DIgSILENT PowerFactory. The overall results can be summarized by focusing on the capacity of DGs and the location of DGs, which are important factors capable of affecting the reliability indices.
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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.
;
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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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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Analysis of interturn fault characteristics in single phase transformer using experimental setup
(2017-01-30)
Bunjongjit, S.
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Klomjit, J.
;
Ngaopitakkul, A.
This paper aims to study characteristics of interturn fault in a single-phase transformer using an experimental setup. Conventional dry-type single-phase transformer rated of 15 kVA and voltage of 220/440 V has been used in the experiment. The winding of transformer was separated as three sub-coils and to evaluate characteristics of interturn fault, the short-circuit between the sub-coil of high voltage side has been performed as the interturn fault. The obtained results show that the behavior of the winding fault is important for developing a fault detection scheme.
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The Analysis of Lightning Strikes to MEA's Distribution Lines on Different Impact Positions
(2017-01-01)
Sestasombut, P.
;
Ngaopitakkul, A.
This paper focuses on behaviour of voltage across insulator when the lightning strikes on different impact positions of Metropolitan Electricity Authority (MEA) 24 kV distribution lines in Thailand. The simulations and analysis are performed using Alternative Transients Program/Electromagnetic Transients Program (ATP/EMTP) to investigate the voltage across insulator. The results indicate that when the lightning strikes to phase conductor or shielding failure occurs, the voltage across insulator where the terminal point is more than the middle point is about 1.5 times. This case, the ground resistance and grounding distance of overhead ground wire (OHGW) is not influential on the voltage across insulator. However, in case the lightning strikes to OHGW, the voltage across insulator where the terminal point is more than the middle point is about 1.2 times and the ground resistance as well as grounding distance of OHGW plays an important role for the voltage across insulator. The analysis shows that when the lightning strikes to the terminal line are considerably more severe than the middle line. Therefore, the lightning protection should be specially considered at the terminal point. The peak current magnitude and the front time lightning current waveform are essential parameters when observing the voltage across insulator. However, the tail time is not an important parameter with regard to the voltage across insulator.
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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.
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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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Characteristics and behaviour of transient current during lightning strikes on transmission tower
(2015-01-01)
Lertwanitrot, P.
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Kettranan, P.
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Itthisathienkul, P.
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Ngaopitakkul, A.
This paper investigates on the characteristics of current when lightning strikes on the conductor of transmission lines. The impedance of multistory model based on the 115 kV transmission tower is employed to simulate in EMTP/ATPDraw program. The location of lightning strikes on the conductor on transmission lines and the ground resistance is varied. The characteristics of the peak amplitudes and the first peak time of current waveform are observed. The obtained results show that when lightning striking occurs near the substation, the peak amplitudes of current tend to increase with decreasing distance between the substation and the lightning location. In addition, the first peak time tends to decrease with decreasing distance between the substation and the lightning location, and its change will be very useful in the development of lightning location scheme.
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An experimental setup investigation to study characteristics of fault on transmission system
(2015-01-01)
Yindeesap, P.
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Ngaopitakkul, A.
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Pothisarn, C.
;
Jettanasen, C.
This paper proposes the experimental setup for studying the characteristics of fault caused by balance and unbalance on a transmission system. The parameters of transmission system (inductance and capacitance) are calculated based on forms of transmission tower, size of conductor, types of conductor and arrangement of transmission line and, they normalized to obtain the values in the π- equivalent circuit model at voltage level of 400 V. In addition, the ATP/EMTP is used to compare the simulated results with the experimental setup in order to show the advantage of the experimental setup. The obtained results show that the similarity between the two waveforms. The experimental setup will be useful in the development of short-circuit protection system in laboratory.
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A study an impact of daylight with period time on illuminance and uniformity for building
(2015-01-01)
Sripramong, S.
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Ananwattanaporn, S.
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Ngaopitakkul, A.
;
Jettanasen, C.
The daylight can be applied for lighting system in building to reduce energy consumption. Although the illuminance on the task area can be increased using the daylight but various factors must be taken into account. This research aims to study an impact of illuminance with daylight in term of each time period. The illuminance is calculated with daylight function in DIALux program. In addition, the fluorescent T5 tube lamp is used in simulation. The case study room without daylight (base case) is compared, in term of illuminance, with the case study room with daylight of each time period. The obtained results show that the daylight can increase the illuminance in the building so the lighting system in many modern buildings has applied daylight in order to achieve specific result of energy savings. The obtained results are useful for design of the interior lighting system.
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Impact of multi-distributed generation on key parameter in distribution system
(2015-01-01)
Ananwattanaporn, S.
;
Ngaopitakkul, A.
In recent year Distributed generation (DG) has become a point of interest in many countries due to several advantages such as improvement in power reliability, reduction of loss in transmission system, improved efficiency in network and lower environment impact. With this much benefit many networks working on integrate renewable energy source DG to the grid connection. Although it has many advantages, installation of DG in distribution network create several effect on the system. One of major effect is the fault current during a grid disturbance because DG changes the grid contribution to the fault current depending on the penetration level, locations and type of DGs, the operation of the protective system can be affected. In network that already has DG connected installing a new DG in network result in significant chance in fault current. Many research has been done such as effect of connecting DG in distribution network. This paper proposes an impact of multi-DG on distribution system characteristic when fault occur. System under studied is 22-kv distribution network with photovoltaic (PV) array and Wind Power Generation using PSCAD/EMTP program. Key parameter such as System current, voltage were obtained in simulation. Result from simulation reveal that DG has an effect on distribution system characteristic. Obtaining data from research can be used to design protection system for distribution system in the future.

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