Özgül SALOR-DURNA

Proceedings Paper | 2023 | IEEE Industry Applications Society Annual Meeting

The research work presented in this paper proposes a method for modeling the behavior of the Electric Arc Furnace (EAF) currents for a tap-to-tap time based on the DFT amplitude histograms of the EAF current waves. The method is used to model the EAF current behavior separately for each phase of the EAF operation: boring, melting and refining. The model is verified by comparing the THD histograms and the flicker measurements of the original and modeled EAF current waveforms. The proposed model can be used as an EAF model in the simulation environment for various purposes before the installation of an EAF. The method has low computat . . .ional load compared to various other techniques, since it utilizes only the amplitude distribution parameters of the first 13 frequency components and the one-cycle signal representing the higher order harmonics. The model is novel in the sense that every time the EAF current signal is generated, a unique waveform reflecting the corresponding distributions is generated, which is compatible with the random behavior of the EAF operation. Keyword: EAF current; EAF modeling; electric arc furnace (EAF); power quality; steel makin More less

Mirbek TURDUEV

Article | 2023 | Physica Scripta98 ( 1 )

With the discovery of self-accelerating beams, possibility of obtaining curved light beams in free space has been realized. These special beams paved the way for many new applications as well as the exploration of novel beam types. Recently, great research effort has been conducted to realize different types of curved beams such as photonic hook and airy beam. These curved types of beams are obtained by introducing structural asymmetry or applying non-uniform dielectric distribution to the input and output face of the structure. With this regard, we propose specially designed asymmetric structure with polynomial back surface which g . . .enerates curved light beams. Proposed lossless dielectric structure can generate curved beams at frequencies varying from 15.78 GHz to 20.09 GHz and corresponding curvature angles of minimum 41.34 degrees and maximum 57.58 degrees, respectively. The physical background of the curved beam formation is based on interference of the exiting light waves that diffract on upper and bottom polynomial surfaces which provides phase modulation leading to the curved trajectory of the propagating light. In addition, the observed beam steering effect is further investigated and the experimental verification in microwave region is conducted to verify our design's operation principle More less

Mehmet ERTUĞRUL

Article | 2023 | APL Materials11 ( 7 )

New fluorescent materials with a low cost, hypotoxicity, and concealment are desired for the application of anti-counterfeiting. Herein, we report a CsCu2I3@Cs3Cu2I5 composite with a triple-mode photoluminescence (PL) feature by simply adjusting the excitation wavelengths, which are ascribed to the multiple excited states of different phases in the CsCu2I3@Cs3Cu2I5 composite. The broadband emission and high quantum yield (∼51) of the composite originate from the structure-oriented self-trapped excitons effect of Cs3Cu2I5 and CsCu2I3 phases. Moreover, the incorporation of polyethylene oxide (PEO) into this composite improves the stab . . .ility of CsCu2I3@Cs3Cu2I5@PEO against harsh environments. The CsCu2I3@Cs3Cu2I5@PEO composite has a slight decay of ∼5 of its initial PL intensity and only a 3.5 shift of the corresponding color coordinate after 30 days of storage. More importantly, its initial PL intensity shows only 10.3 decay under ultraviolet exposure for 200 h. Our work provides a promising approach to design materials for advanced anti-counterfeiting applications. Keyword: excitons; fluorescent materials; photoluminescence; band emission; solid state chemistry; photochemical reaction More less

Özgül SALOR-DURNA

Proceedings Paper | 2023 | IEEE Industry Applications Society Annual Meeting

In this paper, utilization strategies for battery energy storage systems (BESS) are assessed in order to reduce the unscheduled power flows in the interconnection lines caused by multiple electric arc furnace operations in Turkey. Turkish electricity network is synchronously connected to the European Network of Transmission System Operators for Electricity (ENTSO-E) via 3 EHV transmission lines. Extensive amount of intermittent loads like electric arc furnaces (EAF) in the electricity network cause unscheduled power deviations at the intertie lines hence Area Control Error (ACE) performance decreases. Therefore, automatic generation . . . control (AGC) operated by the Transmission System Operator (TSO) requires more automatic Frequency Restoration Reserve (aFRR or Secondary Reserves) capacity to counteract the intermittent EAF loads. Nevertheless, the fast nature of EAF loads cannot be followed by the traditional generators participating in aFRR to keep the ACE between required performance limits. In order to mitigate the effects of these highly fluctuating loads on ACE, different AGC models incorporating BESS as secondary reserves in AGC is investigated. Time synchronized measurements collected for 17 major EAFs are used as disturbance to the power system. A two area dynamic simulation model comprising IEEE 14 bus and IEEE 118 bus models with AGC models are used to simulate the ACE variation between ENTSO-E and Turkey. Since batteries will be in high cyclic aging stress due to fast control signals, battery aging performance is also investigated. It is shown that BESS systems are effective in mitigating the unscheduled power flows due to the multiple EAF operations. Keyword: automatic generation controller (AGC); battery energy storage systems(BESS); electric arc furnace (EAF); state of charge (SOC); unscheduled power flows. dynamic simulatio More less

Özgül SALOR-DURNA

Proceedings Paper | 2021 | IEEE Industry Applications Society Annual Meeting

In this research work, deep machine learning based methods together with a novel data augmentation are developed for predicting flicker, voltage dip, harmonics and interharmonics originating from highly time-varying electric arc furnace (EAF) currents and voltage. The aim with the prediction is to counteract both the response time delays and reaction time delays of active power filters (APFs) specifically designed for electric arc furnaces (EAF). Multiple synchronous Reference frame (MSRF) analysis is used to decompose the frequency components of the EAF current and voltage waveforms into dqo components. Then using low pass filters . . .and prediction of the future values of these dqo components, reference signals for APFs are generated. Three different methods have been developed. In two of them, a low pass Butterworth filter is used together with a linear FIR based prediction or long short term memory network (LSTM) for prediction. In the third method, a deep convolutional neural network (CNN) combined with and LSTM network is used to filter and predict at the same time. For a 40 ms prediction horizon, the proposed methods provide 2.06, 0.31, 0.99 prediction errors of the dqo components for the Butterworth and linear prediction, Butterworth and LSTM and CNN with LSTM, respectively. The error of the predicted reconstructed waveforms of flicker, harmonics, and interharmonics resulted in 8.5, 1.90, and 3.2 reconstruction errors for the above-mentioned methods More less

Özgül SALOR-DURNA

Proceedings Paper | 2023 | Proceedings

This paper presents a deep-learning based method for the classification of transient events of the power system using the data collected by a standard Phasor Measurement Unit (PMU). Although transient power system events are high-frequency variations of the voltages and currents, it leaves a trace in the PMU time-series data, which are collected at relatively much lower-frequencies. The main motivation of this study is to use low-frequency data recorded by PMU devices, widely used in the industry, for the classification of transient events, which would normally require the use of high-cost power quality analyzers. In the proposed me . . .thod, PMU data are converted into 2D data by Gramian Angular Field (GAF) image transformation method to increase the classification performance. Then, the GAF matrices corresponding to PMU time-series data are classified by a Convolutional Neural Network (CNN) based deep learning method. Transient event data used in this research work includes different numbers of frequency and angle time series of three different events, Line Trip, Generation Trip and Load Shedding, obtained from the Frequency Disturbance Recorders (FDR) developed at Virginia Tech. FDRs are connected to the FNET/GridEye network hosted by the University of Tennessee. Classification performances on the three power system events show that using only the frequency data gives the best performance results compared to that using angle only and both frequency and angle. Impact of the training data amount is examined for all cases and future work is proposed. Although there are similar studies in the literature, contribution of this research work is revealing the effect of PMU data type and size of training set in detail. Keyword: convolutional neural network; frequency disturbance recorder; gramian angular field; phasor measurement unit; power quality; power system transient; transient event classificatio More less

Mehmet ERTUĞRUL

Article | 2021 | IEEE Transactions on Geoscience and Remote Sensing60 ( Published online: 02 July 2021 )

A free-space time-domain method is proposed to retrieve dielectric constant (epsilon r), conductivity (sigma e), and thickness (d) of metal-backed low-loss dielectric samples using calibration-independent reflected power peak measurements. Its algorithm is validated by numerical calculations and simulations (CST Microwave Studio) using a sine-modulated Gaussian window. A sensitivity analysis is followed to examine its performance considering the dependencies of reflected power peaks with respect to epsilon r and sigma e. Free-space time-domain measurements have been implemented after transforming frequency-domain measurements into t . . .ime-domain ones to extract epsilon r, sigma e, and d of polypropylene, polyethylene, and polyoxymethylene samples More less

Özgül SALOR-DURNA

Article | 2021 | IEEE Transactions on Industry Applications57 ( 6 )

In this research work, a deep learning (DL)-based method for the fast and accurate analysis of current harmonics of electric arc furnaces (EAF) is proposed. For such a system, a large amount of EAF current data is required for the training phase of the DL-based structure, which is not only a thorny but also an expensive procedure. Hence, the second focus of this research work is to gain the ability to generate EAF currents with realistic harmonic contents based on a much smaller amount of field data of EAF currents. For this purpose, EAF current data, recorded at a transformer substation supplying an EAF plant during a tap-to-tap ti . . .me of the EAF operation, are examined in terms of harmonic component amplitudes and phases. Then, a significantly larger amount of EAF current data is regenerated based on the statistics of current harmonics mimicking the real EAF behavior and this synthetic data are used to train the DL-based harmonic estimator. This estimator is able to estimate both amplitudes and phases of the harmonics without computing any time- or frequency-domain features during the estimation process. Hence, the outcomes of this research work are twofold: First, detailed analysis of the EAF current harmonic behavior is achieved, which reveals the operation principles of the EAF. Second, a DL-based harmonic estimator is trained, which is able to output the amplitude and phase estimations directly out of waveform samples without any feature extraction. The proposed system aims to serve the needs of active power filters of the EAF installations in the electricity system, since it has been shown that fast and accurate harmonic amplitude and phase estimations are obtained. Ключев More less

Mehmet ERTUĞRUL

Article | 2021 | Waves in Random and Complex Media ( Published online: 22 Jul 2021 )

A feasible extraction procedure is proposed to retrieve the diagonal tensor elements of the permittivity and permeability, and the magnetoelectric coupling coefficient of Omega-type biansiotropic metamaterials (MMs). The procedure is based on the state transition matrix approach and uses non-iterative closed-form expressions between constitutive parameters and scattering (S-) parameters to achieve such determination using S-parameters for normal incidence and oblique incidence of TE and TM modes (a desirable feature from practical point of view). S-parameter simulations of a bianisotropic MM slab constructed by edge-coupled resonato . . .rs are performed using a 3D electromagnetic simulator program and used to validate the proposed procedure and compare its accuracy against previously developed extraction procedures. The effects of incidence angle, S-parameter More less

Mirbek TURDUEV

Article | 2022 | Journal of Physics D: Applied Physics55 ( 21 )

Logic gates have great importance in realization of rapid data transmission as well as low loss transfers. In this paper, a multi-objective inverse-design approach is implemented by using objective-first algorithm to design optical AND, OR, NAND and NOT logic gates on Si-platform at the design wavelength of 1.30 mu m. For all gates, the design area is fixed to 2.24 mu m x 2.24 mu m. The optical logic '1' output is accepted to be optical power values greater than 0.8 times of the input optical power. By implementing a Bias waveguide as well as two input ports, we made it possible to achieve logic '1' output for logic operations havin . . .g no inputs such as '0 NAND 0 1' and '0 NOT 1'. We binarized the proposed logic gates, and then numerically analyzed them by using finite-difference time-domain method. Proposed AND gate yields 1.20 times of input power for '1 AND 1 1' logic operation and highest logic '0' is obtained for logic operation of '1 AND 0 0' as 0.40 times of the input power at the operating wavelength. It is also observed that proposed logic gates can operate not only at the design wavelength of 1.30 mu m but also at broad wavelength regions as well. Finally, we demonstrate that it is possible to carry out complex logic operations by combining the proposed logic AND, OR and NAND gates to construct an XOR gate in the same platform More less

Özgül SALOR-DURNA

Article | 2020 | IET Generation, Transmission & Distribution14 ( 19 )

In this study, a new method for the analysis of harmonic components in the power system based on a deep learning (DL) framework is introduced. In the proposed method, both amplitudes and phases of the harmonic components can be estimated accurately, unlike most of the research work in the literature, which usually focus on estimating amplitudes only. A convolutional neural network (CNN) structure is used to estimate the phases and amplitudes of harmonics, although CNN is usually used for classification. It has been shown that the proposed DL-based method can satisfactorily estimate both amplitudes and phases of the power system harm . . .onics inside a 20-ms window and this makes the proposed method suitable for possible real-time applications, such as active power filtering of the harmonics. It has also been shown that the proposed method is robust to fundamental frequency changes. Experiments on carefully-generated data sets to reflect the power system behaviour show that the proposed method demonstrates remarkably good performance in terms of estimation accuracy, especially for time-varying frequency cases. Average error for the amplitude estimation is obtained as 0.21% and that for the phase is 9 degrees, which outperforms the other compared analyses methods in cases of fundamental frequency variations More less

Mehmet ERTUĞRUL

Article | 2021 | Measurement182

Metamaterial (MM) slabs in close proximity can couple with one another. This coupling can modify the electromagnetic response of the overall MM structure involving individual MM resonators. The signal flow graph technique along with the ABCD parameters are applied to quantitatively and qualitatively examine this coupling from simulated/measured scattering parameters of cascade connection of closely or largely separated MM slabs. S-parameter measurements of a MM slab constructed by split-ring-resonators were carried out at X-band (8.2-12.4 GHz) to validate our theoretical analysis.