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2014

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Articles 7051 - 7080 of 7238

Full-Text Articles in Engineering

Control Of Svc Based On The Sliding Mode Control Method, Ercan Köse, Hakan Kizmaz, Kadi̇r Abaci, Saadetti̇n Aksoy Jan 2014

Control Of Svc Based On The Sliding Mode Control Method, Ercan Köse, Hakan Kizmaz, Kadi̇r Abaci, Saadetti̇n Aksoy

Turkish Journal of Electrical Engineering and Computer Sciences

A genetic algorithm (GA)-based sliding mode controller is proposed to improve the voltage stability of a power system with a static var compensator. The proposed controller is examined for improving the load bus voltage, which changes under different demanding powers, and its performance for transient analysis is compared with the Ziegler--Nichols proportional-integral (ZNPI), Lyapunov-based sliding mode control (LASMC), and GA-based proportional-integral-derivative (GAPID) controllers. The dynamic equations, consisting of a 2-bus nonlinear system, are converted to a mathematical description of sliding mode techniques. The optimum values of the sliding mode controller and proportional-integral-derivative (PID) coefficients that are required are calculated using …

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Multiple-Global-Best Guided Artificial Bee Colony Algorithm For Induction Motor Parameter Estimation, Abdul Ghani Abro, Junita Mohamad Saleh Jan 2014

Multiple-Global-Best Guided Artificial Bee Colony Algorithm For Induction Motor Parameter Estimation, Abdul Ghani Abro, Junita Mohamad Saleh

Turkish Journal of Electrical Engineering and Computer Sciences

An induction motor is the most commonly used motor in industry today. Motor circuit parameters are essential for designing, evaluating performance, and controlling the applications of the motor. However, it is difficult to measure the electric parameters, e.g., resistance and reactance, of induction motors accurately. Therefore, researchers have noted the parameter estimation of induction motors as an essential optimization problem. The artificial bee colony (ABC) algorithm is an efficient element of bioinspired optimization algorithms and has been successfully applied in numerous engineering applications. However, the ABC algorithm suffers from slow convergence and poor exploitation. Additionally, there are bleak chances of …

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Removing Random-Valued Impulse Noise In Images Using A Neural Network Detector, İlke Türkmen Jan 2014

Removing Random-Valued Impulse Noise In Images Using A Neural Network Detector, İlke Türkmen

Turkish Journal of Electrical Engineering and Computer Sciences

This paper proposes a new method using an artificial neural network to remove random-valued impulse noise (RVIN) in images. The inputs of the neural model used to detect the RVIN are formed using basic and related gradient values. The detection of the noisy pixels is realized in 3 phases using the proposed neural detector. In order to obtain a more robust detector, 2 different networks, which are trained with an artificial training image corrupted with high and low clutter densities, are used. The extensive simulation results show that the proposed method is significantly better than the compared filters in terms …

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Robust Stability Of Linear Uncertain Discrete-Time Systems With Interval Time-Varying Delay, Mehmet Nur Alpaslan Parlakçi Jan 2014

Robust Stability Of Linear Uncertain Discrete-Time Systems With Interval Time-Varying Delay, Mehmet Nur Alpaslan Parlakçi

Turkish Journal of Electrical Engineering and Computer Sciences

This paper presents a robust stability problem for linear uncertain discrete-time systems with interval time-varying delay and norm-bounded uncertainties. First, a necessary and sufficient stability condition is obtained by employing a well-known lifting method and switched system approach for nominal discrete-time delay systems. Both the stability method of checking the characteristic values inside the unit circle and a Lyapunov function-based stability result are taken into consideration. Second, a simple Lyapunov--Krasovskii functional (LKF) is selected, and utilizing a generalized Jensen sum inequality, a sufficient stability condition is presented in the form of linear matrix inequalities. Third, a novel LKF is proposed …

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Perceptual Quality Evaluation Of Asymmetric Stereo Video Coding For Efficient 3d Rate Scaling, Nükhet Özbek, Gi̇zem Ertan, Oktay Karakuş Jan 2014

Perceptual Quality Evaluation Of Asymmetric Stereo Video Coding For Efficient 3d Rate Scaling, Nükhet Özbek, Gi̇zem Ertan, Oktay Karakuş

Turkish Journal of Electrical Engineering and Computer Sciences

In 3D perception, the binocular suppression of the human vision, perceiving high quality 3D video in the case of a view in higher quality, can be exploited in asymmetric stereo video coding for efficient 3D rate scaling. Hence, the best stereo rate-visual distortion performance may be gained by asymmetric coding, which is the reduction of the spatial and/or quantization resolution of the low-quality view, while keeping the high-quality view in full resolution. However, how to determine the level of asymmetry and what type of scaling should be chosen are still in question. In this work, we try to assess the …

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Optimal Operation Management Of Microgrids Using The Point Estimate Method And Firefly Algorithm While Considering Uncertainty, Sirus Mohammadi, Babak Mozafari, Soodabeh Solimani Jan 2014

Optimal Operation Management Of Microgrids Using The Point Estimate Method And Firefly Algorithm While Considering Uncertainty, Sirus Mohammadi, Babak Mozafari, Soodabeh Solimani

Turkish Journal of Electrical Engineering and Computer Sciences

This paper analyzes the behavior of Hong's point estimate method to account for uncertainties in probabilistic energy management systems to optimize the operation of a microgrid (MG). These uncertainties may arise from different sources, such as the market prices, load demands, and electric power generation of wind farms and photovoltaic systems. Point estimate methods constitute a remarkable tool to handle stochastic power system problems because good results can be achieved using the same routines as those corresponding to deterministic problems, while keeping the computational burden low. The problem is formulated as a nonlinear constraint optimization problem to minimize the total …

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Source Microphone Identification From Speech Recordings Based On A Gaussian Mixture Model, Ömer Eski̇dere Jan 2014

Source Microphone Identification From Speech Recordings Based On A Gaussian Mixture Model, Ömer Eski̇dere

Turkish Journal of Electrical Engineering and Computer Sciences

Microphone identification is a specific type of media forensics that investigates whether it is possible to identify the source microphone from speech recordings. The main aim of this study is to find out which of the several feature extraction techniques are best suited to the source microphone identification systems. We perform microphone identification experiments with 16 different microphones using 3 datasets. In order to improve the results on the datasets, we also investigate the important parameters that may affect the microphone identification performance. Our experimental results show that the proposed method is comparable to the existing studies in a closed-set …

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Retinal Image Analysis Using Multidirectional Functors Based On Geodesic Conversions, Saleh Shahbeig Jan 2014

Retinal Image Analysis Using Multidirectional Functors Based On Geodesic Conversions, Saleh Shahbeig

Turkish Journal of Electrical Engineering and Computer Sciences

A retinal image contains vital information. Extracting these features is the first and most important step in the analysis of retinal images for various applications of medical or human recognition. In this study, a morphological-based blood vessel extraction algorithm using adaptive-local analysis from colored retinal images is proposed. In this algorithm, by applying the appropriate morphology functors and local histogram stretching on the retinal images, the brightness of the images is considerably uniformed. Furthermore, curvelet transform (CT) is used to enhance the retinal images by highlighting the edges of the images in various scales and directions and by the adaptive …

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Recurrent Wavelet Neural Network Control Of A Pmsg System Based On A Pmsm Wind Turbine Emulator, Chih Hong Lin Jan 2014

Recurrent Wavelet Neural Network Control Of A Pmsg System Based On A Pmsm Wind Turbine Emulator, Chih Hong Lin

Turkish Journal of Electrical Engineering and Computer Sciences

A recurrent wavelet neural network (NN)-controlled 3-phase permanent magnet synchronous generator system (PMSG), which is direct-driven by a permanent magnet synchronous motor (PMSM) based on a wind turbine emulator, is proposed to control the output values of a rectifier (or AC to DC power converter) and inverter (or DC to AC power converter) in this study. First, a closed-loop PMSM drive control based on a wind turbine emulator is designed to generate the maximum power for the PM synchronous generator (PMSG) system according to different wind speeds. Next, the rotor speed of the PMSG, the DC bus voltage, and the …

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Impact Of Plug-In Hybrid Electric Vehicle Charging/Discharging Management On A Microgrid, Kiamars Kaveh, Seyed Mehdi Hakimi, Seyed Masoud Moghaddas-Tafreshi, Fazllolah Naseri Jan 2014

Impact Of Plug-In Hybrid Electric Vehicle Charging/Discharging Management On A Microgrid, Kiamars Kaveh, Seyed Mehdi Hakimi, Seyed Masoud Moghaddas-Tafreshi, Fazllolah Naseri

Turkish Journal of Electrical Engineering and Computer Sciences

Plug-in hybrid electric vehicles (PHEVs) may replace conventional vehicles in most urban areas and populated cities due to their lower levels of air pollution compared to internal combustion engine (ICE) vehicles. PHEVs can increase the ability of residential complexes to participate in demand-side management, as well. This paper explores the potential of PHEVs as a flexible load in order to satisfy 2 main issues: increasing the penetration rate of renewable energy in a microgrid and increasing the load factor. In this study, 3 scenarios for managing PHEV charging and discharging are considered. The first scenario connects PHEVs to the grid …

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Discovery Of Hydrometeorological Patterns, Mete Çeli̇k, Fi̇li̇z Dadaşer Çeli̇k, Ahmet Şaki̇r Dokuz Jan 2014

Discovery Of Hydrometeorological Patterns, Mete Çeli̇k, Fi̇li̇z Dadaşer Çeli̇k, Ahmet Şaki̇r Dokuz

Turkish Journal of Electrical Engineering and Computer Sciences

Hydrometeorological patterns can be defined as meaningful and nontrivial associations between hydrological and meteorological parameters over a region. Discovering hydrometeorological patterns is important for many applications, including forecasting hydrometeorological hazards (floods and droughts), predicting the hydrological responses of ungauged basins, and filling in missing hydrological or meteorological records. However, discovering these patterns is challenging due to the special characteristics of hydrological and meteorological data, and is computationally complex due to the archival history of the datasets. Moreover, defining monotonic interest measures to quantify these patterns is difficult. In this study, we propose a new monotonic interest measure, called the hydrometeorological …

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Simultaneous Identification And Correction Of Measurement And Branch Parameter Errors, Mehdi Ahmadi Jirdehi, Mehrdad Tarafdar Hagh, Kazem Zare Jan 2014

Simultaneous Identification And Correction Of Measurement And Branch Parameter Errors, Mehdi Ahmadi Jirdehi, Mehrdad Tarafdar Hagh, Kazem Zare

Turkish Journal of Electrical Engineering and Computer Sciences

The performance of the state estimation (SE) depends on the accuracy of the received measured data, as well as the parameter data of the power system. In this paper, a new algorithm is proposed for the simultaneous identification and correction of measurement and branch parameter errors (series and shunt admittances) in the power system SE problem. The proposed method uses Lagrange multipliers for the identification and correction of branch parameter errors without the need for a-priori specification of suspect parameter vectors. Erroneous measurements and branch parameter values can be corrected using the proposed method to estimate the measurement and branch …

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Shuffled Frog Leaping Algorithm Optimization For Ac--Dc Optimal Power Flow Dispatch, Abolfazl Rahiminejad, Arash Alimardani, Behrooz Vahidi, Seyed Hossein Hosseinian Jan 2014

Shuffled Frog Leaping Algorithm Optimization For Ac--Dc Optimal Power Flow Dispatch, Abolfazl Rahiminejad, Arash Alimardani, Behrooz Vahidi, Seyed Hossein Hosseinian

Turkish Journal of Electrical Engineering and Computer Sciences

In this paper, a simple-implemented and reliable AC--DC optimal power flow (OPF) is proposed. Although high-voltage direct current (HVDC) transmission lines are being increasingly used in power systems, new optimization algorithms such as evolutionary and memetic algorithms, which never stick in local minimum, so far have not been implemented in the AC--DC OPF problem. An evolutionary algorithm known as the shuffled frog leaping algorithm (SFLA) is proposed in this paper to solve the OPF dispatch in an AC--DC power system (including both high-voltage alternating current and HVDC transmission lines). The implementation of the AC--DC OPF with these kinds of methods …

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Multifunction Converter Based On Lyapunov Function Used In A Photovoltaic System, Trung Nhan Nguyen, An Luo Jan 2014

Multifunction Converter Based On Lyapunov Function Used In A Photovoltaic System, Trung Nhan Nguyen, An Luo

Turkish Journal of Electrical Engineering and Computer Sciences

The development of distributed generations (DGs) is essential to help solve energy crises and improve the reliability of electricity supplies. However, the involvement of a DG in a grid along with an increase of the nonlinear load will reduce the power quality. To solve this problem, we want the converter used in the DG to work flexibly, intelligently, and more accurately. To contribute to the improvement of quality of the DG, this paper proposes a multifunction converter (MFC) model. With the proposed model, the photovoltaic generator, which can be operated at harmonic suppression, and the power injection are more flexible …

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Fuzzy Impedance And Force Control Of A Stewart Platform, Selçuk Ki̇zi̇r, Zafer Bi̇ngül Jan 2014

Fuzzy Impedance And Force Control Of A Stewart Platform, Selçuk Ki̇zi̇r, Zafer Bi̇ngül

Turkish Journal of Electrical Engineering and Computer Sciences

A new, simple, and effective control method is proposed for the position-based impedance and force control of a Stewart platform (SP). The control approach can be divided into 3 parts, namely position control in free space, impedance control in contact, and force control. An impedance filter is developed to achieve the desired behavior between the position and force. The gain of the filter is modified by a fuzzy logic proportional-integral-derivative controller. Kinematic and dynamic models of the SP are simulated in a MATLAB/Simulink environment. Several real-time experiments are conducted with the SP developed in our laboratory. The results of the …

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Fuzzy Logic Approach To Henry Factor For Distributed Feedback Laser Case, Abdullah Çavuşoğlu Jan 2014

Fuzzy Logic Approach To Henry Factor For Distributed Feedback Laser Case, Abdullah Çavuşoğlu

Turkish Journal of Electrical Engineering and Computer Sciences

In this study, a simple approach for intelligent modeling of the Henry factor (\alpha-alpha parameter, antiguiding factor, phase-amplitude coupling factor) or the so-called linewidth enhancement factor, which is an actual analysis and design parameter for semiconductor laser diodes and optical communication systems, is proposed based on the fuzzy logic (FL) phenomenon. The proposed FL-based model easily computes the Henry factor in terms of different wavelengths and injection current levels (i.e. the inputs of the model). The experimental data belong to a distributed feedback laser, obtained from amplified spontaneous emission spectra, which is among the techniques required for the characterization of …

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Model-Based Robust Chaotification Using Sliding Mode Control, Aykut Kocaoğlu, Cüneyt Güzeli̇ş Jan 2014

Model-Based Robust Chaotification Using Sliding Mode Control, Aykut Kocaoğlu, Cüneyt Güzeli̇ş

Turkish Journal of Electrical Engineering and Computer Sciences

Chaos is a complex behavior of dynamical nonlinear systems that is undesirable in most applications and should be controlled; however, it is desirable in some situations and should be generated. In this paper, a robust chaotification scheme based on sliding mode control is proposed for model based chaotification. A continuous time single input observable system is considered such that it is subject to parameter uncertainties, nonlinearities, noises, and disturbances, which are all additive to the input and can be modeled as an unknown function but bounded by a known function. The designed dynamical state feedback control law forces the system …

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Performance Evaluation Of The Wave Atom Algorithm To Classify Mammographic Images, Nebi̇ Gedi̇k, Ayten Atasoy Jan 2014

Performance Evaluation Of The Wave Atom Algorithm To Classify Mammographic Images, Nebi̇ Gedi̇k, Ayten Atasoy

Turkish Journal of Electrical Engineering and Computer Sciences

The most common type of cancer seen in women is breast cancer. To enable recovery from this severe disease, monitoring and early detection must be provided, and related precautions must be taken as a first step. During diagnosis, some cases may be overlooked due to fatigue and eyestrain, because the determination of abnormalities is a repetitive procedure. In this study, a computer-aided diagnosis (CAD) system, using the wave atom transform (WAT) algorithm and support vector machine (SVM), is proposed to evaluate mammography images. During the process, the region of interest (ROI) is defined before applying the method. The system includes …

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A New Edge-Preserving Algorithm Based On The Cie- Lu'v' Color Space For Color Contrast Enhancement, Mohammad Zolfaghari, Mehran Yazdi Jan 2014

A New Edge-Preserving Algorithm Based On The Cie- Lu'v' Color Space For Color Contrast Enhancement, Mohammad Zolfaghari, Mehran Yazdi

Turkish Journal of Electrical Engineering and Computer Sciences

Image segmentation and edge detection are the most important presteps in machine vision, and their successfulness can affect the success of the next steps. In this paper, the performance of the Trahanias edge detector in different color spaces, such as RGB, YCbCr, HSI, and CIE Lu'v', is compared in order to find the best color space for image segmentation and edge detection. We then offer an efficient edge-preserving algorithm for color contrast enhancement in the CIE Lu'v' space. The proposed algorithm can increase the color contrast, which causes a remarkable improvement in image segmentation and edge detection in the CIE …

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New Throughput-Based Antenna Selection Scheme, Mohammad Lari, Abbas Mohammadi, Abdolali Abdipour Jan 2014

New Throughput-Based Antenna Selection Scheme, Mohammad Lari, Abbas Mohammadi, Abdolali Abdipour

Turkish Journal of Electrical Engineering and Computer Sciences

In this paper, a new throughput-based transmit antenna selection (AS) scheme is evaluated. First, a closed-form solution for the throughput rate of a multiple-input multiple-output (MIMO) system, with a truncated selective repeat automatic repeat request (TSR-ARQ) or selective repeat plus go-back-N automatic repeat request (SR+GBN-ARQ) protocol at the data link layer, is proposed. In addition, a throughput-based AS technique with adaptive modulation is also investigated. For this purpose, the throughput and packet error rates of a MIMO system with a transmit AS and TSR-ARQ protocol at the data link layer are analyzed. This study is conducted in 2 different cases. …

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A Low-Order Nonlinear Amplifier Model With Distributed Delay Terms, Ahmet Hayretti̇n Yüzer, Şi̇mşek Demi̇r Jan 2014

A Low-Order Nonlinear Amplifier Model With Distributed Delay Terms, Ahmet Hayretti̇n Yüzer, Şi̇mşek Demi̇r

Turkish Journal of Electrical Engineering and Computer Sciences

In this paper, a novel behavioral modeling technique for the characterization of memory effects of amplifiers is proposed. This characterization utilizes asymmetric intermodulation distortion (IMD) components, which are the result of a 2-tone excitation of a nonlinear amplifier. These asymmetric IMD components are represented basically by a power series, where each term in the series has its own time delay term. These time delay terms successfully justify the presence of asymmetry in the intermodulation components, which leads to the prediction of amplitude-to-amplitude and amplitude-to-phase distortions. The parameters of the model are extracted using 2-tone measurements. A 100-W peak power amplifier …

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Expert Doctor Verdis: Integrated Medical Expert System, Aytürk Keleş Jan 2014

Expert Doctor Verdis: Integrated Medical Expert System, Aytürk Keleş

Turkish Journal of Electrical Engineering and Computer Sciences

Innovative medical technologies are developing day by day, as there is an important need for integrated medical expert systems (ESs) that will help to effectively manage and control diagnosis and treatment processes. These systems, with new approaches, have improved the experiences and capabilities of physicians to make the diagnosis of diseases. In this work, an integrated medical ES called Expert Doctor Verdis (Ex-Dr Verdis) is developed, which combines an advanced medical information system containing various medical services supported by information technologies, with ES capabilities in a single system. This system is also one kind of decision support system. Implementation of …

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Comparison Of Different Methods For Determining Diabetes, Mehmet Recep Bozkurt, Ni̇lüfer Yurtay, Zi̇ynet Yilmaz, Cengi̇z Sertkaya Jan 2014

Comparison Of Different Methods For Determining Diabetes, Mehmet Recep Bozkurt, Ni̇lüfer Yurtay, Zi̇ynet Yilmaz, Cengi̇z Sertkaya

Turkish Journal of Electrical Engineering and Computer Sciences

In this study, the Pima Indian Diabetes dataset was categorized with 8 different classifiers. The data were taken from the University of California Irvine Machine Learning Repository's web site. As a classifier, 6 different neural networks [probabilistic neural network (PNN), learning vector quantization, feedforward networks, cascade-forward networks, distributed time delay networks (DTDN), and time delay networks], the artificial immune system, and the Gini algorithm from decision trees were used. The classifier's performance ratios were studied separately as accuracy, sensitivity, and specificity and the success rates of all of the classifiers are presented. Among these 8 classifiers, the best accuracy and …

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A Novel Hybrid Recurrent Wavelet Neural Network Control Of Permanent Magnet Synchronous Motor Drive For Electric Scooter, Chih Hong Lin Jan 2014

A Novel Hybrid Recurrent Wavelet Neural Network Control Of Permanent Magnet Synchronous Motor Drive For Electric Scooter, Chih Hong Lin

Turkish Journal of Electrical Engineering and Computer Sciences

Due to the electric scooter with nonlinear uncertainties, e.g., nonlinear friction force of the transmission belt, the linear controller was made to disable speed tracking control. In order to overcome this problem, a novel hybrid recurrent wavelet neural network (NHRWNN) control system is proposed to control for a permanent-magnet synchronous motor-driven electric scooter in this study. The NHRWNN control system consists of a supervised control, a recurrent wavelet neural network (RWNN), and a compensated control with adaptive law. According to the Lyapunov stability theorem and the gradient descent method, the on-line parameter training methodology of the RWNN can be derived …

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An Artificial Neural Network Approach For Sensorless Speed Estimation Via Rotor Slot Harmonics, Hayri̇ Arabaci Jan 2014

An Artificial Neural Network Approach For Sensorless Speed Estimation Via Rotor Slot Harmonics, Hayri̇ Arabaci

Turkish Journal of Electrical Engineering and Computer Sciences

In this paper, a sensorless speed estimation method with an artificial neural network for squirrel cage induction motors is presented. Motor current is generally used for sensorless speed estimation. Rotor slot harmonics are available in the frequency spectrum of the current. The frequency components of these determined harmonics are used to estimate the speed of the motor in which the number of rotor slots is given. In the literature, individual algorithms have been used to calculate the speed from the slot harmonics. Unlike the literature, in the proposed method, an artificial neural network is used to extract the speed from …

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A Control Scheme Employing An Adaptive Hysteresis Current Controller And An Uncomplicated Reference Current Generator For A Single-Phase Shunt Active Power Filter, Hüseyi̇n Doğan, Ramazan Akkaya Jan 2014

A Control Scheme Employing An Adaptive Hysteresis Current Controller And An Uncomplicated Reference Current Generator For A Single-Phase Shunt Active Power Filter, Hüseyi̇n Doğan, Ramazan Akkaya

Turkish Journal of Electrical Engineering and Computer Sciences

In recent years, active power filters (APFs) have become popular because of their excellent current harmonics and reactive power mitigation ability. The performance of the APF is directly related to the selected control strategy, which is mainly divided into 2, the reference current generation and current control. Most of the reference current generation methods are very complicated and require precise mathematical expressions. Moreover, being the most preferred current control method, conventional hysteresis controllers have a fixed bandwidth, which causes different total demand distortion values under different load conditions. In this study, a novel control scheme for a single-phase shunt APF …

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Stability Analysis Of Multimachine Thermal Power Systems Using The Nature-Inspired Modified Cuckoo Search Algorithm, Shivakumar Rangasamy, Panneerselvam Manickam Jan 2014

Stability Analysis Of Multimachine Thermal Power Systems Using The Nature-Inspired Modified Cuckoo Search Algorithm, Shivakumar Rangasamy, Panneerselvam Manickam

Turkish Journal of Electrical Engineering and Computer Sciences

The stability of modern interconnected thermal power systems is greatly affected by the presence of low-frequency inertial oscillations in the system, due to various forms of disturbances experienced. This paper provides an efficient damping solution to these oscillations based on nature-inspired modified cuckoo search algorithm-based controller design. The proposed controller design is formulated as a parameter optimization problem based on damping ratio and time-domain error deviations. The effectiveness of the proposed damping controller design is illustrated by performing the nonlinear time domain simulations of the test multimachine power systems under various operating conditions and disturbances. Moreover, an exhaustive comparative stability …

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Application Of Hilbert--Huang Transform And Support Vector Machine For Detection And Classification Of Voltage Sag Sources, Alireza Foroughi, Ebrahim Mohammadi, Saeid Esmaeili Jan 2014

Application Of Hilbert--Huang Transform And Support Vector Machine For Detection And Classification Of Voltage Sag Sources, Alireza Foroughi, Ebrahim Mohammadi, Saeid Esmaeili

Turkish Journal of Electrical Engineering and Computer Sciences

Power quality disturbances, including voltage sag, swell, harmonics, flicker, and notch, are one of the main concerns for industries and electrical equipment. Among these disturbances, voltage sag, due to its irrecoverable economic effects on industries, is particularly important. In this paper, the detection and classification of voltage sag sources containing motor starting, short circuit, transformer energizing, and the reacceleration of motors after fault clearance using the Hilbert--Huang transform (HHT) and support vector machine (SVM) are studied. A voltage sag waveform includes several oscillating modes; for separating these oscillating modes, which are called intrinsic mode functions (IMFs), empirical mode decomposition is …

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New Approach Using Structure-Based Modeling For The Simulation Of Real Power/Frequency Dynamics In Deregulated Power Systems, Mostafa Eidiani, Hossein Zeynal Jan 2014

New Approach Using Structure-Based Modeling For The Simulation Of Real Power/Frequency Dynamics In Deregulated Power Systems, Mostafa Eidiani, Hossein Zeynal

Turkish Journal of Electrical Engineering and Computer Sciences

Load frequency control (LFC) is one of the significant ancillary services in the electricity markets. The major concerns with LFC models have long been their dynamic response and complexity, as well as market price sensitivity. To cater to the complexity of the dynamic model that is introduced by the LFC and algebraic constraints by the transmission network, the differential-algebraic equation is transformed into a set of ordinary differential equations. This is done by differentiating the network constraints under a certain assumption that can be held throughout the system. To make the model suitable in a market environment, the real power …

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Reliability-Based Maintenance Scheduling Of Generating Units In Restructured Power Systems, Mahmud Fotuhi Firuzabad, Farrokh Aminifar, Abbas Shahzadeh Jan 2014

Reliability-Based Maintenance Scheduling Of Generating Units In Restructured Power Systems, Mahmud Fotuhi Firuzabad, Farrokh Aminifar, Abbas Shahzadeh

Turkish Journal of Electrical Engineering and Computer Sciences

Maintenance scheduling of generating units in restructured power systems is a collaborative and interactive process between independent system operators (ISOs) and generating companies (GENCOs). The ISO should comply with GENCO maintenance preferences subject to targeted system reliability levels. This process might be multistage since the admission of all initial unit outage requests may threaten system reliability. Hence, the ISO accepts some proposals and determines alternatives for the remaining units. The GENCOs are then allowed to confirm the alternatives or revise them. In this paper the ISO problem of generating unit maintenance scheduling is tackled. The objective function is to minimize …

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