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28,593 Article Results

Comparison of FACTS Devices for Two Area Power System Stability Enhancement using MATLAB Modelling

10.11591/ijape.v3.i2.pp130-139
J. N. Rai , Naimul Hasan , B. B. Arora
Modern Power Transmission networks are becoming increasingly stressed due to growing demand and restrictions on building new lines. Losing stability is one of the major threat of such a stressed system following a disturbance. Flexible ac transmission system (FACTS) devices are found to be very effective in a transmission network for better utilization of its existing facilities without sacrificing the desired stability margin. The static synchronous compensator (STATCOM) and Static Var Compensator (SVC) are the shunt devices of the flexible AC transmission systems (FACTS) family. When system voltage is low, STATCOM generates reactive power and when system voltage is high it absorbs reactive power whereas the Static Var compensator provides the fast acting dynamic compensation in case of severe faults. In this Paper, the performance of SVC is compared with the performance of STATCOM. Proposed controllers are implemented using MATLAB/SIMULINK. Simulation results indicate that the STATCOM controller installed with two machine systems provides better damping characteristics in rotor angle as compared to two machine system installed with SVC. Thus, transient stability enhancement of the two machine system installed with STATCOM is better than that installed with SVC.
Volume: 3
Issue: 2
Page: 130-139
Publish at: 2014-08-01

Cognitive Sensor Platform

https://ijece.iaescore.com/index.php/IJECE/article/view/5521
Mark McDermott
This paper describes a platform that is used to build embedded sensor systems for low energy implantable applications. One of the key characteristics of the platform is the ability to reason about the environment and dynamically modify the operational parameters of the system. Additionally the platform provides to ability to compose application specific sensor systems using a novel computational element that directly supports a synchronous-dataflow (SDF) programming paradigm. Cognition in the context of a sensor platform is defined as the “process of knowing, including aspects of awareness, perception, reasoning, and judgment”.DOI:http://dx.doi.org/10.11591/ijece.v4i4.5680
Volume: 4
Issue: 4
Page: 520-531
Publish at: 2014-08-01

Towards An Accurate Modeling of Frequency-dependent Wind Farm Components Under Transient Conditions

10.11591/ijape.v3.i2.pp90-104
M. A. Abd-Allah , Mahmoud N. Ali , A. Said
Frequency dependence complete model is set up for describing the lightning transient behavior of the wind turbines (WTs).To get an appropriate wind turbine model, a high frequency models of surge arrester protecting the boost transformer, transformer and ground electrode soil ionization are implemented. The transient responses and Ground Potential Rise (GPR) can be obtained at different locations in the WTs and connected grid in the time domain as well as in the frequency domain using Fast Fourier Transform (FFT). To check the validity of the model, Surge arresters protection level at different locations, at i.e. LV, MV and HV, is compared with ABB manufacture data sheet, Also a comparison has been made between simple and frequency dependence model of overall wind farm components using ATP/EMTP. This paper provides an accurate simulation of wind farm components under transient condition.
Volume: 3
Issue: 2
Page: 90-104
Publish at: 2014-08-01

Modeling and Simulation of SVPWM Based Application

10.11591/ijape.v3.i2.pp140-148
Ashish Porwal , Ketan Baria , Anuradha Deshpande
Recent developments in power electronics and semiconductor technology have lead to widespread use of power electronic converters in the power electronic systems. A number of Pulse width modulation (PWM) schemes are used to obtain variable voltage and frequency supply from a three-phase voltage source inverter. Among the different PWM techniques proposed for voltage fed inverters, the sinusoidal PWM technique has been popularly accepted. But there is an increasing trend of using space vector PWM (SVPWM) because of their easier digital realization, reduced harmonics, reduced switching losses and better dc bus utilization. This project focuses on step by step development of SVPWM technique. Simulation results are obtained using MATLAB/Simulink software for effectiveness of the study.
Volume: 3
Issue: 2
Page: 140-148
Publish at: 2014-08-01

Ash Cooler Heat Recovery Under Energy Conservation Scheme

10.11591/ijape.v3.i2.pp105-114
Vikash R Gupta , Lalatendu Pattanayak
A healthy fluidization state in circulating fluidized-bed combustion (CFBC) combustor is attributed to proper quantity of hot bed material (ash), which acts as a thermal fly-wheel. It receives & stores thermal energy from the burning of fuel (lignite) & distributes uniformly throughout the combustor & helps in maintaining a sustained combustion. The quantity of bed ash inside the combustor or size of the bed, depends upon boiler load & subsequently upon combustor temperature, lignite feed rate and ash % in lignite. As these parameters varies during process continuously, sometimes it becomes necessary to drain out the ash from the combustor. As & when differential pressure across the bed is increased from a justified level, draining of hot bed ash starts into Ash Coolers. Bed ash is drained at very high temperature of 850 oC & it also contains burning particles of lignite. This paper describes the heat recovery from bed ash, unloaded from the combustor into ash cooler, by pre-heating the condensate water of turbine cycle in a 125 MW CFB boiler of Surat Lignite Power Plant in India. The thermal performance of ash cooler was derived by doing a heat balance calculation based on the measured temperature of ash and cooling water with different load. From the heat balance calculation influence of ash temperature and ash amount on heat transfer coefficient is determined. Simulation is carried out around main turbine cycle indicates improved thermal economy of the unit, higher plant thermal efficiency, lower plant heat rate and reduce fuel consumption rate. Also simulation result shows that the heat transfer coefficient increase with ash amount and decreases with increase in ash temperature.
Volume: 3
Issue: 2
Page: 105-114
Publish at: 2014-08-01

The Comparative Study between Twisted and Non-Twisted Distribution Line for Photovoltaic System Subjected to Induced Voltage Generated by Impulse Voltage

10.11591/ijeecs.v12.i8.pp5774-5778
Nur Hidayu Abdul Rahim , Zikri Abadi Baharudin , Md Nazri Othman , Puteri Nur Suhaila Ab Rahman
The recent advancement of renewable energy sources and specifically photovoltaic system has resulted in outdoor installations of large power stations. A photovoltaic system is exposed to extreme ambient conditions due to the lightning strike activity that generated induced overvoltage which have a high tendency to affect the electrical apparatus especially renewable energy plant that directly exposed to this source. This study is performed through experimental work by comparing the effect of induced overvoltage propagation upon between the twisted and non-twisted distribution line for photovoltaic system. The induced voltage is performed by using lightning impulse generator. It is found that the maximum voltage of the unwanted signal is proportional with the distant of the specimen. The closer distant between solar panel material and spark discharge, the more serious effect would occur due to the induced overvoltage.
Volume: 12
Issue: 8
Page: 5774-5778
Publish at: 2014-08-01

Assessment of Electric Field Distribution Inside 500/220 kV Open Distribution Substations During Working Conditions

10.11591/ijape.v3.i2.pp115-123
Sayed A. Ward , Samy M. Ghania , Essam M. Shaalan
The high level electric field intensity produced by high voltage (HV) equipments inside 500/220 kV substations is harmful for the human (staff) health. Therefore the minimum health and safety requirements regarding the exposure of workers to the risk arising from electric fields produced inside these substations is still considered as a competitive topic for utility designers, world health organization (WHO) and biomedical field researchers. It is very important to have knowledge about levels distribution of electric field intensity within these high voltage substations as early stage in the process of substation design. This paper presents results of investigation 50Hz electric field intensity distribution inside 500/220 kV power transmission substations in Cairo, Egypt. This paper presents a method for assessment the distribution of 50HZ electric field intensity distribution inside this substation, this method of analysis is based on the charge simulation technique (CSM). This study will serve for planning service works or for inspection of equipment on HV power transmission substations.
Volume: 3
Issue: 2
Page: 115-123
Publish at: 2014-08-01

Implementation of Hybrid Generation Power System in Pakistan

10.11591/ijape.v3.i2.pp75-81
Qazi Waqar Ali , Muhammad Aamir , Arshad Nawaz , Zaki Udin , Shahid Ullah
A solar-wind hybrid power generation system has been presented here. The application based system illustrated in this paper is designed on the basis of the solar and wind data for Pakistan. The power generated by the system is intended for domestic use. The most common source of unconventional power in homes is battery based UPS (Uninterrupted power supply) inverter. The UPS inverter charges the battery with conventional grid power. This system will charge the battery of UPS inverter by using only wind and solar power, which will make the system cost effective and more reliable. The reason for using both solar and wind is that recent studies have proven that combined system can be more productive and consistent and other thing is that neither of them can be used for continuous power generation. In the system illustrated in this paper the solar-wind system provides power periodically which is controlled by electronic methods and a microcontroller is used to monitor the power from both the inputs. The switching action is provided from the microcontroller to the battery charging based on the power received from solar photovoltaic panel and wind generators. In this paper, an efficient system has been presented comprising of solar panel, wind generator, charge controller and charge storage unit (battery). Solar panel is selected as the main input and the wind resource will be used only in the absence of the solar photovoltaic (PV) output.
Volume: 3
Issue: 2
Page: 75-81
Publish at: 2014-08-01

Nonuniform Defect Detection of Cell Phone TFT-LCD Display

10.11591/ijeecs.v12.i8.pp6036-6046
Jahangir Alam S.M. , Hu Guoqing
Uneven and Nonuniformity (Mura) of Thin Film Transistor Liquid Crystal Display (TFT-LCD) is a major problem of cell phone display. The different types of uneven and nonuniformity are decreased the performance of TFT-LCD. To economize and increase its performance, it is necessary to detect these kinds of defects. The cause of these types of noisy defects can be stimulated by the material of TFT, intensity of back light, total internal reflection, mirror form of others materials, internal light, and external light. The energy loss and gain in LCD display is another issue to make these uneven and nonuniformity. The objective of this study is to investigate and detect the defects of cell phone display considering some parameters with image analysis. The back side and the front side of the defects have been observed to find the uniqueness of that defects and its model.
Volume: 12
Issue: 8
Page: 6036-6046
Publish at: 2014-08-01

A Complete Combinatorial Solution for a Coins Change Puzzle and Its Computer Implementation

10.11591/ijeecs.v12.i8.pp6338-6345
Daxin Zhu , Xiaodong Wang
In this paper, we study a combinatorial problem encountered in monetary systems. The problem concerned is to find an optimal solution R(k; n) of a combinatorial problem for some positive integers k and n. To the authors' knowledge, there is no eficient solutions for this problem in the literatures so far. We first show how to find an eficient recursive construction algorithm based on the backtracking search strategy. Furthermore, we can give an explicit formula for finding the maximal elements of the solution. Our new techniques have improved the time complexities of the search algorithm dramatically.
Volume: 12
Issue: 8
Page: 6338-6345
Publish at: 2014-08-01

Evolution Process of a Broadband Coplanar- Waveguide-fed Monopole Antenna for Wireless Customer Premises Equipment

10.11591/ijeecs.v12.i8.pp6238-6242
Alishir Moradikordalivand , Tharek A. Rahman , Ali N. Obadiah , Mursyidul Idzam Sabran
In this paper a design process of a broadband printed monopole antenna using stepped cut at four corners (CSFC) technique is proposed. The CSFC is a technique that four corners a patch (rectangular/square) of planar monopole antennas are cut in order to enhance the impedance bandwidth. The technique can be used to design any different types of planar monopole antenna in specific frequency ranges. Therefore, to become more acquaintance with the CSFC technique an evolution process of single band to broadband antenna is represented. However, the proposed antenna is designed for wireless indoor customer premises equipment (CPE) using the coplanar waveguide (CPW) feeding technique. Moreover, the antenna is simulated using CST software and also fabricated and tested so as to validate the results. The simulated and measured -10 dB reflection bandwidth is 104% (850MHz to 2.7 GHz) to cover GSM (900 and 1800 MHz), WiFi (2.4 GHz) and LTE (2.6 GHz) applications. High efficiency and gain as well as omnidirectional and quasi-omnidirectional of radiation pattern at lower and upper frequencies have been achieved.
Volume: 12
Issue: 8
Page: 6238-6242
Publish at: 2014-08-01

Three-Stage Amplifier Adopting Dual-Miller with Nulling-Resistor and Dual-Feedforward Techniques

10.11591/ijeecs.v12.i8.pp6055-6062
Zhou Qianneng , Li Qi , Li Chen , Lin Jinzhao , Li Hongjuan , Li Yunsong , Pang Yu , Li Guoquan , Cai Xuemei
A high-gain wide-bandwidth three-stage amplifier, which employs dual-miller compensation with nulling-resistor and dual-feedforward compensation (DMCNR-DFC), is designed and analyzed in this paper. By adopting the technique of DMCNR-DFC, the designed three-stage amplifier achieves well performance including gain-bandwidth product (GBW) and slew rate (SR). The improved DMCNR-DFC three-stage amplifier is designed and simulated in 0.5μm BCD process. Simulation results show that DMCNR-DFC three-stage amplifier achieves a dc gain of about 121.1dB and GBW of about 6.1MHz with 52º phase margin using a 5-V power supply voltage.
Volume: 12
Issue: 8
Page: 6055-6062
Publish at: 2014-08-01

A Grey Relation Analysis Method to Vibration Fault Diagnosis of Hydroelectric Generating Set

10.11591/ijeecs.v12.i8.pp5729-5735
Wang Ruilian , Gao Shengjian
Aiming to the complexity of vibration fault cause, the great many of fault parameters in hydroelectric generating set, and the superiority of grey relation analysis for its no strict requirement to fault sample capacity and regularity, the weighted grey relation model is built to look for the vibration fault type. The fuzzy matrix's transformation arithmetic is used to obtain the weight vectors of the grey relation coefficient, thus the weighted coefficient is the weighted grey relation model. The relation coefficient between reference sequence and compare sequence in vibration fault sample is provided by synthetic arithmetic of fuzzy weight to diagnose the vibration fault type. The grey relation coefficient weighted by fuzzy synthetic arithmetic, which is not only made the established weight be a scientific basis, but also can “sensitive” highlight the vibration fault type of hydroelectric generating set. Thus the problem of looking for every fault types is better resolved. By analyzing the practical example, it proved that the weighted grey relation model in the paper can effectively diagnose the vibration fault type of hydroelectric generating set and it has definite applicability.
Volume: 12
Issue: 8
Page: 5729-5735
Publish at: 2014-08-01

Simulation of Cascaded H-Bridge Multilevel Inverter Based DSTATCOM

10.11591/ijeecs.v12.i8.pp5720-5728
Rammohan Rao Makineni , C.N. Bhaskar
This paper presents an investigation of five-Level Cascaded H – bridge (CHB) Inverter as Distribution Static Compensator (DSTATCOM) in Power System (PS) for compensation of reactive power and harmonics. The advantages of CHB inverter are low harmonic distortion, reduced number of switches and suppression of switching losses. The DSTATCOM helps to improve the power factor and eliminate the Total Harmonics Distortion (THD) drawn from a Non-Liner Diode Rectifier Load (NLDRL). The D-Q reference frame theory is used to generate the reference compensating currents for DSTATCOM while Proportional and Integral (PI) control is used for capacitor dc voltage regulation. A CHB Inverter is considered for shunt compensation of a 11 kV distribution system. Finally a level shifted PWM (LSPWM) and phase shifted PWM (PSPWM) techniques are adopted to investigate the performance of CHB Inverter. The results are obtained through Mat lab / Simulink software package.
Volume: 12
Issue: 8
Page: 5720-5728
Publish at: 2014-08-01

SVC Placement for Voltage Profile Enhancement Using Self-Adaptive Firefly Algorithm

10.11591/ijeecs.v12.i8.pp5976-5984
Selvarasu Ranganathan , Surya Kalavathi. M
Static VAR Compensator (SVC) is one of the shunt type FACTS devices for providing reactive power support in power systems network and its placement representing the location and size has significant influence on enhancement of voltage profile. This paper presents a firefly algorithm based optimization strategy for placement of SVC in power systems with a view of minimizing voltage deviation at the load buses to enhance the load bus voltages. This method uses a self-adaptive scheme for tuning the firefly parameters. The proposed strategy is tested on three IEEE test systems. The obtained results are promising and show the effectiveness of the proposed approach.
Volume: 12
Issue: 8
Page: 5976-5984
Publish at: 2014-08-01
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