Browsing by Author "Seker, S"

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    Spectral and statistical analysis for ferroresonance phenomenon in electric power systems
    Seker, S; Akinci, TC; Taskin, S
    This study presents our findings on the ferroresonance phenomenon for the Seyitomer-Isiklar part of the Electric Power System of 380 kV in Turkey. In this context, the power spectral density approach and Short-Time Fourier Transforms are applied to the voltage variations for phase R of the sample power network. The findings show that the ferroresonance event can be represented by the interharmonics between 50 and 250 Hz, as well as statistical properties. In addition, a histogram of the ferroresonance region shows a different characteristic from the overall data and the non-ferroresonance region. This different characteristic can be defined by an asymmetrical distribution characteristic, and its numerical measure is given by the Noise to Signal Ratio of 0.624.
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    Reverse Power Data Analysis and Feature Extraction Based Upon Continuous Wavelet Transform for Electric Power Plants
    Taskin, S; Seker, S; Irgen, B; Akinci, TC
    This study is focused on the investigating of a power plant generator in reverse power condition. For this purpose, reverse power data were collected from a Combined Heat and Power Plant generator protection relay. The reverse power conditions were evaluated by means of the time-frequency and time-scale methods. As a result of this evaluation, it can be said that the time-frequency and lime-scale properties of the signals like current, voltage, frequency, active and reactive powers were extracted with all details. Copyright (C) 2010 Praise Worthy Prize S.r.l. - All rights reserved.
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    A neural network based approach to estimate of power system harmonics for an induction furnace under the different load conditions
    Gokozan, H; Taskin, S; Seker, S; Ekiz, H
    This study presents an artificial neural network based intelligent monitoring algorithm to detect of a power system harmonics. The proposed approach was tested on the current and voltage data of an induction furnace power system, which was collected by using a LabVIEW based measurement system under different load conditions. The collected data was analyzed with MATLAB program using the short-time Fourier transform and power spectral density estimation methods to find the dominant harmonics of the power system. After determination of the operational region in terms of the harmonic levels under the full-load condition, the power spectral density algorithm was used for determining the stationary intervals of the power system data. Identified harmonic frequencies were used to train the artificial neural network algorithm, which was then tested for harmonic estimation at different load conditions. Hence, the neural network topology was used as a artificial follower. Results demonstrate that harmonic state estimation of a power system can be achieved by an error variation at the output of the auto-associative neural network.
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    INVESTIGATING THE EFFECT OF JOINT BEHAVIOR ON THE OPTIMUM DESIGN OF STEEL FRAMES VIA HUNTING SEARCH ALGORITHM
    Dogan, E; Seker, S; Saka, MP; Kozanoglu, C
    This study aims to carry out the effect of beam-to-column connections on the minimum weight design of steel plane frames In the practical analysis of steel frames, end connections are assumed to be either fully restrained or pin-connected. However, experiments reveal that the real behavior is between these extremes and should be taken into account for the realistic design of structures. Hunting search algorithm is used for the automation of optimum design process. It is a numerical optimization method inspired by group hunting of animals such as wolves and lions. It is proven that it is a reliable and efficient technique for obtaining the solution of discrete structural optimization problems. Present design algorithm developed on the basis of hunting search algorithm selects w- sections for the members of semi rigid steel frame from the complete list of w- sections given in LRFD- AISC (Load and Resistance Factor Design, American Institute of Steel Construction). The design constraints are implemented from the specifications of the same code which covers serviceability and strength limitations. The selection of w-sections is carried out such that the design limitations are satisfied and the weight of semirigid frame is the minimum. In order to demonstrate its efficiency, three different steel frames are designed by the optimum design algorithm presented. The designs obtained by use of this algorithm are also compared with the ones produced by particle swarm optimization method.
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    Numerical analysis on corrosion resistance of mild steel structures
    Erdem, RT; Seker, S; Ozturk, AU; Gucuyen, E
    Corrosion resistances of mild steel specimens according to artificial neural network (ANN) analysis were investigated in the scope of this study. Corrosion rate values were taken into numerical analysis as a result of experimental studies under corrosive aggressive media. Mild steel specimens were selected according to the section type varieties such as box, tube and cornier. All steel specimens were subjected to the aggressive media formed using sodium chloride (NaCl with 99.8 % purity) solutions with 3.5, 5.0 and 7.0 % ratios per one liter distilled water and only distilled water. The reduction in corrosion rate has been observed and considered according to some corrosion loss respects. Corrosion rate prediction models were established between corrosion rate and parameters such as mass loss obtained by experimental studies using ANN. ANNs are computing systems that simulate the biological neural systems of the human brain. In this study, ANN analysis was generated to predict the corrosion rate values after experimental studies. Experimental and predicted values were compared by each other and it is seen that a strong relationship was established between them.
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    Early age corrosion of mild steel in aggressive media
    Ozturk, AU; Gucuyen, E; Erdem, RT; Seker, S
    Effects of the time of holding, type of section, and concentration of the solution on the early age corrosion of mild steel are studied. Section types for steel specimens were box, tube, and corner. They were subjected to 3.5%, 5.0%, and 7.0% NaCl solutions. It was established that the concentration of the solution affects the corrosion until reaching the saturation value.
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    Computer - Aided Learning in Engineering Education
    Seker, S
    This paper discusses the role of computer-aided learning (CAL) in engineering education. In this study, some descriptions about computer aided learning were explained. Existing engineering education are handled and definition, importance and quality of education was expressed. In recent years, the positive results seen that the use of computer aided learning in engineering education. Computer-aided design (CAD), computer aided manufacturing (CAM) and computer aided engineering (CAE) is becoming increasingly popular. Therefore, computer's have become very essential for applications in engineering and in engineering education. Computer training and computer assisted instruction should be expanded. Visual thinking and design before you build the object as a tool available to perform by computer. Thus, experiments that cannot be done in the laboratory, it is possible to make with the virtual laboratory that was generated by computer. Engineering educations goal is to develop design capabilities and computer-based training is the best tool for this purpose. (C) 2013 The Authors. Published by Elsevier Ltd.
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    Detection of static eccentricity for permanent magnet synchronous motors using the coherence analysis
    Akar, M; Taskin, S; Seker, S; Çankaya, I
    This paper reports on work to detect the static eccentricity faults for permanent magnet synchronous motor (PMSM) using spectral analysis methods. Measurements are carried out by collecting the stator current and voltage, torque and speed for healthy and faulty cases of the motor. Static eccentricity case is formed by changing the rotor position in the manner of sliding the shaft on a horizontal axis. As a result of the spectral analysis for the motor currents, side band effects appeared at around the fundamental frequency are determined as a most important indicator of the eccentricity. In addition to this determination, the eccentricity problem is observed from the torque and rotor speed data comparing with each others as well as current and voltage variations.
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    Spectral Analysis for Current and Temperature Measurements in Power Cables
    Taskin, S; Seker, S; Karahan, M; Akinci, TC
    This research aims to detect spectral properties under thermal and current variations for power cables. Therefore, spectral diversities are exposed under current unbalances and different load conditions through the spectral analysis techniques. Also, huge load variations are easily detected from the current signals in the time-frequency plane using the short-time frequency analysis. Hence, this study presents the determination of the frequency characteristics and spectral similarities between the phase currents and thermal variations.
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    AN APPLICATION OF DENOISING BASED ON WAVELET TRANSFORM FOR TEMPERATURE SIGNALS OF THE ALTERNATORS IN A PASSENGER COACH
    Taskin, S; Akinci, TÇ; Seker, S
    This paper deals with a passenger coach alternators. In this study, temperature variations, which are depended on load conditions of alternators in a passenger coach, have been investigated using the wavelet transform based denoising and statistical methods. To obtain real road data from the bus alternators, the bus was driven 456 km on the roadway in Turkey. During the collecting alternators data, interior lighting lambs on/off locations, air conditioner operation position, bus headlights situations and other electrical/electronic devices on/off positions have been considered. MATLAB program was used for the signal analysis of the alternators.