Articles

Access the latest knowledge in applied science, electrical engineering, computer science and information technology, education, and health.

Advanced Search
Filter Icon

Filters article

Years

FAQ Arrow
Single Year
Range Year
0
0

Source Title

FAQ Arrow

Authors

FAQ Arrow

28,451 Article Results

Wide Area Oscillation Damping using Utility-Scale PV Power Plants Capabilities

10.11591/.v7i2.pp681-691
Mehrdad Moradi , Pouria Maghouli
With increasing implementation of Wide Area Measurement Systems (WAMS) in power grids, application of wide area damping controllers (WADCs) to damp power system oscillations is of interest. On the other hand it is well known that rapidly increasing integration of renewable energy sources into the grid can dangerously reduce the inertia of the system and degrade the stability of power systems. This paper aimed to design a novel WADC for a utility-scale PV solar farm to damp out inter area oscillations while the main focus of the work is to eliminate the impact of communication delays of wide-area signals from the WAMS. Moreover the PV farm impact on inter area oscillation mitigation is investigated in various case studies, namely, with WADC on the active power control loop and with WADC on the reactive power control loop. The Quantum Particle Swarm Optimization (QPSO) technique is applied to normalize and optimize the parameters of WADC for inter-area oscillations damping and continuous compensation of time-varying latencies. The proposed method is prosperously applied in a 16-bus six-machine test system and various case studies are conducted to demonstrate the potential of the proposed structure.
Volume: 7
Issue: 2
Page: 681-691
Publish at: 2017-04-01

Fault Identification of In-Service Power Transformer using Depolarization Current Analysis

10.11591/ijece.v7i2.pp559-567
M.A. Talib , N.A. Muhamad , Z.A. Malek , B.T. Phung
Preventive diagnostic testing of in-service power transformers require system outage and expert’s knowledge and experiences in interpreting the measurement results. The chemical oil analysis may cause significant variance to measurement results due to the different practices in oil sampling, storage, handling and transportation. Thus, a cost effective measuring technique by means of a simpler method that is able provide an accurate measurement results is highly required. The extended application of Polarization and Depolarization Current (PDC) measurement for characterization of different faults conditions on in-service power transformer has been presented in this paper. The oil sample from in-service power transformers with normal and 3 different faults type conditions were sampled and tested for Dissolved Gases Analysis (DGA) and PDC measurement. The DGA results was used to confirm type of faults inside the transformer while the PDC pattern of oil with normal, partial discharge, overheating and arcing were correlated to the oil sample conditions. The analysis result shows that depolarization current provides significant information to defferenciate fault types in power transformer. Thus this finding provides a new alternative in identifying incipient faults and such knowledge can be used to avoid catastrophic failures of power transformers.
Volume: 7
Issue: 2
Page: 559-567
Publish at: 2017-04-01

The Weights Detection of Multi-criteria by using Solver

10.11591/.v7i2.pp858-868
Fachrurrazi Fachrurrazi , Yuwaldi Away , Saiful Husin
Multi criteria, which are generally used for decision analysis, have certain characteristics that relate to the purpose of the decision. Multi criteria have complex structures and have different weights depending upon the consideration of assessors and the purpose of the decision also. Expert’s judgment will be used to detect the criteria weights that applied by assessors. The aim of this study is a model to detect the criteria weights and biases on the subcontractor selection and detecting the significant weights, as decisive criteria. A method, which is used to modeling the weights detection, is the Solver Application. Data, totaling 40 sets, has been collected that consist of the assessor’s assessment and the expert’s judgment. The result is a pattern of weights and biases detection. The proposed model have been able to detect of 20 criteria weights and biases, that consist of 4 criteria in  the total weights of 60% (as decisive criteria) and 16 criteria in the total weights of 40%. A model has been built by training process performed by the Solver, which the result for MSE training is 9.73711e-08 and for MSE validation is 0.00900528. Novelty in the study is a model to detect pattern of weights criteria and biases on subcontractor selection by transferring the expert's judgment using Solver Application.
Volume: 7
Issue: 2
Page: 858-868
Publish at: 2017-04-01

Lyot-based Multi-wavelength Fiber Laser

10.11591/.v7i2.pp981-985
Suhairie Saleh , N. A. Cholan , A. H. Sulaiman , M. A. Mahdi
A multi-wavelength fiber laser which is based on a Lyot filter is experimentally demonstrated. A combination of four-wave mixing in a highly nonlinear fiber and Lyot filter mechanism in the laser cavity is able to generate multi-wavelength with relatively high extinction ratio (ER). At the input current of 100mA, six laser lines with ER more than 5 dB are successfully generated. The wavelength spacing for the multi-wavelength is 0.15nm, corresponding to the characteristics of the Lyot filter used.
Volume: 7
Issue: 2
Page: 981-985
Publish at: 2017-04-01

Enhanced Time of Use Electricity Pricing for Industrial Customers in Malaysia

10.11591/ijeecs.v6.i1.pp155-159
Nur Azrina Mohd Azman , Md Pauzi Abdullah , Mohammad Yusri hasan , Dalila Mat Said , Faridah Hussin
New Time of Use (ToU) tariff scheme known as Enhanced ToU (EToU) has been introduced on 1st January 2016 for industrial customers in Malaysia. EToU scheme is the advanced version of current ToU where the daily time frame is divided into six period blocks, as compared to only two in the existing ToU. Mid-peak tariff is introduced on top of peak-hour and off-peak tariff. The new scheme is designed to reduce Malaysia’s peak hour electricity demand. On customer side, they could be benefited from the low off-peak tariff by simply shifting their consumption. However, it depends on their consumption profile and their flexibility in shifting their consumption. Since EToU scheme is voluntary, each customer needs to perform cost-benefit analysis before deciding to switch into the scheme. This paper analyzes this problem by considering EToU tariff scheme for industry and customer’s electricity consumption profile. Case studies using different practical data from different industries are presented and discussed in this paper.
Volume: 6
Issue: 1
Page: 155-159
Publish at: 2017-04-01

Improved Timing Estimation Using Iterative Normalization Technique for OFDM Systems

10.11591/.v7i2.pp905-911
Suyoto Suyoto , Iskandar Iskandar , Sugihartono Sugihartono , Adit Kurniawan
Conventional timing estimation schemes based on autocorrelation experience performance degradation in the multipath channel environment with high delay spread. To overcome this problem, we proposed an improvement of the timing estimation for the OFDM system based on statistical change of symmetrical correlator. The new method uses iterative normalization technique to the correlator output before the detection based on statistical change of symmetric correlator is applied. Thus, it increases the detection probability and achieves better performance than previously published methods in the multipath environment. Computer simulation shows that our method is very robust in the fading multipath channel
Volume: 7
Issue: 2
Page: 905-911
Publish at: 2017-04-01

Generator Assessment of Hydro Power Station Adequacy after Reconstruction from Classical to HIS SF6 Substation

10.11591/.v7i2.pp729-740
Srete Nikolovski , Goran Slipac , Emir Alibašić
Reliability analysis of substations and generator assessment of power plant stations are very important elements in a design and maintenance process. This paper presents a generator adequacy assessment of a classical “H” scheme for an open conventional substation, which is often used, and a new HIS - High Integrated Switchgear with SF6 gas isolation. Generator adequacy indices of both types of classical and HIS switchgear were compared and the results showed a high level of reliability and availability of the HIS presented substation. The input data were the annual reports of Croatian TSO-Transmission System Operator (HOPS) and statistics of operation events of Croatian National Electricity (HEP Inc.). For the HIS substation, the input reliability data were used from relevant international literature since only few of HIS substations are installed in Croatia. The generator is modelled with a three-state Markov state space model and Monte Carlo simulations were used for the generator assessment analysis. Adequacy indices LOLP and EDNS were obtained using DIgSILENT software.
Volume: 7
Issue: 2
Page: 729-740
Publish at: 2017-04-01

Novel 9-Steps Automatic AC Voltage Regulator based on Two Step-down Transformers

10.11591/.v7i2.pp576-583
Hussain Attia
A novel design and simulation results of 9-steps automatic AC voltage regulator based on one step-down transformer is presented in this paper. Avoiding the problem of surge at the AC load during controlling jump steps is done through the proposed design. Accurate and smooth controlling function is achieved as well. Instead of the necessity of increasing the number of taps of the used multi tap transformer for wide controlling range of fluctuated AC  supply voltage, the proposed designed adopts using only two step down transformers with 10 Vrms, and 30 Vrms secondary voltages respectively. Through the controlling of the proposed design of AV voltage regulator, the resultant load voltage is equal the AC supply voltage as well as the suitable voltage step which may one of the following voltages; +40V, +30V, +20V, +10V, 0V, -10V, -20V, -30V, -40V. The electronic design is done Multisim software while the electrical circuit connection of step down transformers and relays contacts that is made by using PSIM software for power circuit design.
Volume: 7
Issue: 2
Page: 576-583
Publish at: 2017-04-01

The Correlation between Surface Tracking and Partial Discharge Characteristics on Pressboard Surface Immersed in MIDEL eN

10.11591/.v7i2.pp631-640
Nur Amirah Othman , Hidayat Zainuddin , Aminuddin Aman , Sharin Abd Ghani , Imran Sutan Chairul
This paper presents the investigation of the surface tracking on pressboard surface immersed in MIDEL eN oil.  In this work, the development of surface discharge was analyzed by correlating the visual records of surface tracking on impregnated pressboard and the partial discharge (PD) activities.  The PD activities during the surface tracking process were analyzed in terms of Phase Resolved Partial Discharge (PRPD) patterns.  Throughout the experiment, surface discharge is found as the development of tree-like patterns in the form of white marks occurring on the oil-pressboard interface.  This phenomenon is generally accepted as the drying out process that involves evaporation and decomposition of the oil molecules in the pressboard pores due to the surface discharge activities on the pressboard surface layer.  The development of surface discharge on the pressboard surface can continue from minutes to months or even years until failure.  Thus, condition monitoring system is important to characterize this type of faulty condition.  The experimental results show that there is the decreasing trend of PD magnitude during the development of white mark hallway of a gap distance which is eventually suffered from an unexpected fault.
Volume: 7
Issue: 2
Page: 631-640
Publish at: 2017-04-01

Implementation of Algorithm for Vehicle Anti-Collision Alert System in FPGA

10.11591/.v7i2.pp775-783
Aiman Zakwan Jidin , Lim Siau Li , Ahmad Fauzan Kadmin
Vehicle safety has becoming one of the important issues nowadays, due to the fact the number of road accidents, which cause injuries, deaths and also damages, keeps on increasing. One of the main factors which contribute to these accidents are human's lack of awareness and also carelessness. This paper presents the development and implementation of an algorithm to be utilized for vehicle anti-collision alert system, which may be useful to reduce the occurrence of accidents. This algorithm, which is to be deployed with the front sensors of the vehicle, is capable of alerting any occurrence of sudden slowing or static vehicles ahead, by sensing the rate of distance change. Furthermore, it also triggers an alert if the driver is breaching the safe distance from the vehicle ahead. This algorithm has been successfully implemented in Altera DE0 FPGA and its functionality was validated via hardware experimental tests.
Volume: 7
Issue: 2
Page: 775-783
Publish at: 2017-04-01

Game-Theoretic Channel Allocation in Cognitive Radio Networks

10.11591/.v7i2.pp986-991
Sangsoon Lim
Cognitive radio networks provide dynamic spectrum access techniques to support the increase in spectrum demand. In particular, the spectrum sharing among primary and secondary users can improve spectrum utilization in unused spectrum by primary users. In this paper, we propose a novel game theoretic channel allocation framework to maximize channel utilization in cognitive radio networks. We degisn the utility function based on the co-channel interference among primary and secondary users. In addition, we embed the property of the adjacent channel intererence to consider real wireless environment. The results show that the utility function converges quickly to Nash equilibrium and achieves channel gain by up to 25 dB compared to initial assignment.
Volume: 7
Issue: 2
Page: 986-991
Publish at: 2017-04-01

Characterization of Acrylonitrile Butadiene Styrene for 3D Printed Patch Antenna

10.11591/ijeecs.v6.i1.pp116-123
Norun Abdul Malek , Athirah Mohd Ramly , Atiah Sidek , Sarah Yasmin Mohamad
3D printing is one of the additive manufacturing technology that has gain popularity for time saving and complex design. This technology increases a degree of flexibility for potential 3D RF applications such as wearable and conformal antennas. This paper demonstrates a circular patch antenna fabricated on 3D printed Acrylonitrile Butadiene Styrene (ABS) filament. The main reason of using a 3D printer is that it is accurate, easy to fabricate of a complex geometry and the ability to create new antennas that cannot be made using conventional fabrication techniques. The ABS material has a tangent loss of 0.0051 and the relative permittivity is 2.74. The thickness of the substrate is 1.25 mm. The simulation has been performed using Computer Simulation Technology (CST). The return loss from simulation software is in good match with measurement which is 12.5dB at 2.44GHz. Hence, from the results obtained, the ABS could be used as a substrate for an antenna.
Volume: 6
Issue: 1
Page: 116-123
Publish at: 2017-04-01

Hybrid Low Complex near Optimal Detector for Spatial Modulation

10.11591/.v7i2.pp818-822
P. Rajani Kumari , K. Chenna Kesava Reddy , K.S. Ramesh
In our previous work maximum throughput in multi stream MIMO is analyzed by overcoming the inter antenna interference. To mitigate the Inter antenna interference spatial modulation can be used. Spatial Modulation(SM) aided MIMO systems are the emerging MIMO systems which are low complex and energy efficient. These systems additionally use spatial dimensions for transmitting information. In this paper a low complex detector based on matched filter is proposed for spatial modulation to achieve near maximum likelihood performance while avoiding exhaustive ML search since MF based detector exhibits a considerable reduced complexity since activated transmitting antenna and modulated amplitude phase modulation constellation are estimated separately. Simulation results show the performance of the proposed method with optimal ML detector, MRC and conventional matched filter methods.
Volume: 7
Issue: 2
Page: 818-822
Publish at: 2017-04-01

Focusing Properties of a Modified Retarding Structure for Linear Electron Accelerators

10.11591/.v7i2.pp741-747
Vladimir Kuz'mich Shilov , Aleksandr Nikolaevich Filatov , Aleksandr Evgen'evich Novozhilov
When using accelerators in industry and medicine, important are the dimensions of the device used, especially the radial ones. In the linear electron accelerators based on a biperiodic retarding structure, which operates in the standing wave mode, there is a possibility to provide focusing of the accelerated particles with the help of high-frequency fields without the use of external focusing elements. In the accelerating cell, due to the presence of the far protruding drift sleeves, the electric field lines become strongly curved, which leads to the appearance in the regions adjacent to these sleeves of a substantial in magnitude radial component of the electric field. The particles entering the accelerating gap experience the action of a force directed toward the axis of the system, and at the exit, of a force directed away from the axis. Under certain conditions, alternation of the focusing and defocusing fields can lead to a general focusing effect. In the paper we study the focusing properties of a modified biperiodic structure with standing wave. The main attention is paid to the possibility of using the focusing properties of the electromagnetic accelerating field for guiding the electron beam through the aperture of the accelerating system, which will lead to a significant reduction in the accelerator sizes. The proposed method can be applied in the calculation and design of linear electron accelerators.
Volume: 7
Issue: 2
Page: 741-747
Publish at: 2017-04-01

Modeling and Simulation of VSI Fed Induction Motor Drive in Matlab/Simulink

10.11591/.v7i2.pp584-595
D. Uma , K. Vijayarekha
The theory of reference frames and switching functions are effective in analyzing the performance of the induction motor fed from VSI (Voltage Source Inverter). In this work, mathematical model of Adjustable Speed Drive (ASD) is developed by taking synchronous reference frame equations for induction motor, switching function concept for VSI and non-switching concept for diode bridge rectifier.  The developed model is implemented using MATLAB/Simulink as it is an important tool for the validation of the proposed model. The performance of induction motor is analysed for different frequencies. The developed model is tested for the steady state behavior of machine drive. The proposed mathematical model is validated by the simulation results.
Volume: 7
Issue: 2
Page: 584-595
Publish at: 2017-04-01
1 2 3
...
1896 1897
Show 1471 of 1897

Discover Our Library

Embark on a journey through our expansive collection of articles and let curiosity lead your path to innovation.

Explore Now
Library 3D Ilustration