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A Novel Protective Logic for Optimal Coordination of Overcurrent Relays
Sajad Samadinasab;
Farhad Namdari;
Nader Shojaei
Indonesian Journal of Electrical Engineering and Computer Science Vol 16, No 3: December 2015
Publisher : Institute of Advanced Engineering and Science
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DOI: 10.11591/ijeecs.v16.i3.pp439-453
Usually coordination of overcurrent relays is done by taking into account the specific structure of the system which does not show the real state of the system. On the other hand, dynamic changes in network can occur due to short circuit conditions, the malfunctioning relays, development, operation and repairs on any part of the power system. Also the most of the new protective schemes are based on a communication channel, which cannot be guaranteed in practice. Therefore, solving the problem of relay coordination is extremely difficult in case of dynamic changes in the network structure and the absence of communication links between some relays. In this article, a novel protective logic based on phasor measurement units (PMUs) data is proposed for optimal coordination of overcurrent relays. In this method, by using the PMU measurements, phasor information can be obtained continuously at any node where PMUs are installed in the power grid. For this purpose, in the first the Optimal PMU placement is determined for full network observability. Then, the dynamic changes of network will be observe by using wide area measurements based on PMUs data. Finally this information is sent via communication links PMUs for the optimal coordination of overcurrent relays. The use of PMU for the coordination of overcurrent relays improve the decision making capability and performance of protective relays and help them to form a reliable and robust protection system. The proposed method is tested on IEEE 8-bus and 14-bus standard networks.
Nodes Deployment Scheme of Heterogeneous Wireless Sensor Network Based on Organic Small Molecule Model
Juwei Zhang;
Yu Wang;
Yachuang Liu;
Qiangyi Li
Indonesian Journal of Electrical Engineering and Computer Science Vol 16, No 3: December 2015
Publisher : Institute of Advanced Engineering and Science
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DOI: 10.11591/ijeecs.v16.i3.pp574-582
For nodes deployment of heterogeneous sensor network, based on different probability sensing models of heterogeneous nodes, refer to organic small molecule model, ‘class molecule’ sensing model of heterogeneous nodes is proposed. Combined with DSmT data fusion model, the changes of network coverage ratio after using the new sensing model and data fusion algorithm is studied. According to the research results, the node-deployment strategy of heterogeneous sensor networks based on organic small molecule model (NHOS) is proposed. Sensor network simulation model is established using MATLAB software, the results show the effectiveness of the algorithm, the coverage of network and detection efficiency of nodes are improved, the lifetime of network is prolonged, energy consumption and the number of deployment nodes is reduced, and the scope of perceiving is expanded. As a result, NHOS can improve the detection performance of the network.
Optimized Operation-Planning of a Microgrid with Renewable Sources and Vehicle to Grid
Asad Waqar;
Shaorong Wang;
Qasim Kamil Mohsin;
Muhammad Zahid
Indonesian Journal of Electrical Engineering and Computer Science Vol 16, No 3: December 2015
Publisher : Institute of Advanced Engineering and Science
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DOI: 10.11591/ijeecs.v16.i3.pp401-408
The microgrid with renewable sources possess stability issues. During the grid-connected mode, these issues are taken care by the external grid. However in case of islanding, the distributed generators within the microgrid, have to take care of these issues independently. It needs additional backup like diesel generation or battery storage, which increases the overall capital and operation costs. With the intervention of the V2G storage, these costs can be saved to some extent. However similar to the renewable sources like wind and solar, the power from V2G is also fluctuating which may lead the microgrid towards an uneconomical operation. Therefore an extensive operation-planning is needed to deal with these uncertainties, for the microgrid to be economically viable. In this context, the stochastic programming has been applied to achieve the optimum results. The stochastic scenarios for wind speed, solar radiation, V2G power and load fluctuation have been generated using the Markov chain Monte Carlo method. The optimized operation-planning aims to minimize the total net present cost, size of the fixed storage and fossil fuel emissions subject to constraints. The simulations have been performed using Matlab/Simulink, HOMER and Excel. The simulation results show that the V2G technology substantially decrease the total net present cost. Moreover for such a microgrid the total net present cost and fossil fuel emissions conflict with each other.
A Hybrid the Nonsubsampled Contourlet Transform and Homomorphic Filtering for Enhancing Mammograms
Khaddouj Taifi;
Rachid Ahdid;
Mohamed Fakir;
Said Safi
Indonesian Journal of Electrical Engineering and Computer Science Vol 16, No 3: December 2015
Publisher : Institute of Advanced Engineering and Science
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DOI: 10.11591/ijeecs.v16.i3.pp539-545
Mammogram is important for early breast cancer detection. But due to the low contrast of microcalcifications and noise, it is difficult to detect microcalcification. This paper presents a comparative study in digital mammography image enhancement based on three different algorithms: homomorphic filtering, unsharp masking and our proposed methods. This latter use a hybrid method Combining contourlet and homomorphic filtering. Performance of the given technique has been measured in terms of distribution separation measure (DSM), target-to-background enhancement measure based on standard deviation (TBES) and target-to-background enhancement measure based on entropy (TBEE). The proposed methods were tested with the referents mammography data Base MiniMIAS. Experimental results show that the proposed method improves the visibility of microcalcification.
Effect of Thermal Annealing Temperatures on MSM Photo Detector Based on Ge-like Micro Flowers in the Dark Mode
M.J. Jawad;
Haider Y. Hammod;
Amer B. Dheyab
Indonesian Journal of Electrical Engineering and Computer Science Vol 16, No 3: December 2015
Publisher : Institute of Advanced Engineering and Science
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DOI: 10.11591/ijeecs.v16.i3.pp502-508
In this research , a current density of J = 7.5 mA/cm2 was applied over a constant duration of 2 h to grow Ge-like microflowers on Si. To fabricate a photodetector, Pd was deposited by RF-sputtering as metal contact with Ge. The samples were subjected to rapid thermal annealing (RTA) in ambient N2 at 100,200° and 300°C for 10 min. By screening the samples from electrical noise, the electrical characteristics through current-voltage measurements were carried out at room temperature before and after annealing. The measurements were performed in the dark, white light and UV illuminations. The forward I-V characteristics were analyzed using standard thermionic emission relation for electron transport from Metal-semiconductor-metal(MSM)with low doping concentration .The saturation current was obtained as the intercept from the straight line of ln I versus V, T. It was found that at 5V, these currents were 2.45 × 10-5, 5.77× 10-5, 6.12× 10-4 A, respectively. Also characteristics of the MSM photodetector, linear and logarithmic forward and reverse bias, at different annealing temperatures: as-deposited, 100°C, 200°C and 300°C in the dark mode.
A New Algorithm for Protection of Small Scale Synchronous Generators Against Transient Instability
Zinat Khosravi;
Alireza Saffarian
Indonesian Journal of Electrical Engineering and Computer Science Vol 16, No 3: December 2015
Publisher : Institute of Advanced Engineering and Science
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DOI: 10.11591/ijeecs.v16.i3.pp454-462
Today, installation of small generators has been increased because of their considerable benefits in distribution systems in distributed generation. One of the most important problems for transient stability is the effects of the faults of system. Small scale generators have low constant inertia and protection relays have slow performance in distribution systems. Therefore transient instability is a probable phenomenon for the systems with these generators. In this paper, dynamic response of generator has been studied in different fault conditions and then by introducing the concept of " critical fault clearing time ", the sensitivity of this time to the fault type and also fault location parameters have been studied. Then a new protection scheme has been proposed to prevent of transient instability for small scale generator. This protection scheme uses a new evolutionary algorithm based on the active power of generator and critical fault clearing time. The proposed relay can prevent of wrong and unwanted performance. Furthermore it can disconnect the generator from the system in three phase fault near of the bus-bar before its instability. Simulation results show reliable performance of the proposed relay against system transients.
Combining Fuzzy Logic and Dempster-Shafer Theory
Andino Maseleno;
Md. Mahmud Hasan;
Norjaidi Tuah
Indonesian Journal of Electrical Engineering and Computer Science Vol 16, No 3: December 2015
Publisher : Institute of Advanced Engineering and Science
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DOI: 10.11591/ijeecs.v16.i3.pp583-590
This research aims to combine the mathematical theory of evidence with the rule based logics to refine the predictable output. Integrating Fuzzy Logic and Dempster-Shafer theory by calculating the similarity between Fuzzy membership function. The novelty aspect of this work is that basic probability assignment is proposed based on the similarity measure between membership function. The similarity between Fuzzy membership function is calculated to get a basic probability assignment. The Dempster-Shafer mathematical theory of evidence has attracted considerable attention as a promising method of dealing with some of the basic problems arising in combination of evidence and data fusion. Dempster-Shafer theory provides the ability to deal with ignorance and missing information. The foundation of Fuzzy logic is natural language which can help to make full use of expert information.
Analysis of Amplify-and-Forward Cooperative Networks with Nakagami-m fading Channels For MRC Diversity Combining
Ali Abdulwahhab Mohammed;
Li Yu;
Manar Al-Kali;
Desheng Wang
Indonesian Journal of Electrical Engineering and Computer Science Vol 16, No 3: December 2015
Publisher : Institute of Advanced Engineering and Science
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DOI: 10.11591/ijeecs.v16.i3.pp546-552
In this paper we study the effect of diversity combining for Nakagami -m fading Channels in the amplify-and-forward cooperative networks.We derive the cumulative density function (CDF), probability density function (PDF) and moment generating function (MGF) for the multiple relay amplify-and-forward network with single half duplex channel maximal ratio combiner (MRC). In this network we investigate the cases of MRC at the destination, as well derive the exact Symbol Error Rate (SER) of M-ary phase-shift keying (M-PSK), and quadrature amplitude modulation (M-QAM) in Nakagami -m fading environment. We present a comparison between M-PSK and M-QAM modulation schemes in some representative scenarios where an arbitrary number of cooperative relays is considered.
Power Transformer Incipient Faults Diagnosis Based on Dissolved Gas Analysis
Osama E. Gouda;
Saber M. Saleh;
Salah Hamdy EL-Hoshy
Indonesian Journal of Electrical Engineering and Computer Science Vol 16, No 3: December 2015
Publisher : Institute of Advanced Engineering and Science
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DOI: 10.11591/ijeecs.v16.i3.pp409-416
Incipient fault diagnosis of a power transformer is greatly influenced by the condition assessment of its insulation system oil and/or paper insulation. Dissolved gas-in-oil analysis (DGA) is one of the most powerfull techniques for the detection of incipient fault condition within oil-immersed transformers. The transformer data has been analyzed using key gases, Doernenburg, Roger, IEC and Duval triangle techniques. This paper introduce a MATLAB program to help in unification DGA interpretation techniques to investigate the accuracy of these techniques in interpreting the transformer condition and to provide the best suggestion for the type of the fault within the transformer based on fault percentage. It proposes a proper maintenance action based on DGA results which is useful for planning an appropriate maintenance strategy to keep the power transformer in acceptable condition. The evaluation is carried out on DGA data obtained from 352 oil samples has been summarized into 46 samples that have been collected from a 38 different transformers of different rating and different life span.
Prototyping a Dedicated Photovoltaic System Datalogger
Benabed Khadidja;
Boudghene Stambouli Amine;
Benabadji Noureddine
Indonesian Journal of Electrical Engineering and Computer Science Vol 16, No 3: December 2015
Publisher : Institute of Advanced Engineering and Science
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DOI: 10.11591/ijeecs.v16.i3.pp488-494
Solar power is a renewable energy seen as one of the primary sources for electricity production in order to meet our daily needs. The conversion operation is sensitive and non-fault tolerant that can occur during operation of the system that affects its overall performance. We propose in this present paper a compact, low power and low-cost datalogger for the control and the monitoring based on a survey measures of five important physical parameters in the management and monitoring of the functioning of an electric system based on solar panels. These measures will be carried out at regular intervals, configurable through a PIC18F4520 microcontroller and stored in a large capacity memory type SD card.