Authors:Umair Shahzad First page: 33 Abstract: Transient stability assessment is an integral part of dynamic security assessment of power systems. Traditional methods of transient stability assessment, such as time domain simulation approach and direct methods, are appropriate for offline studies and thus, cannot be applied for online transient stability prediction, which is a major requirement in modern power systems. This motivated the requirement to apply an artificial intelligence-based approach. In this regard, supervised machine learning is beneficial for predicting transient stability status, in the presence of uncertainties. Therefore, this paper examines the application of a binary support vector machine-based supervised machine learning, for predicting the transient stability status of a power system, considering uncertainties of various factors, such as load, faulted line, fault type, fault location and fault clearing time. The support vector machine is trained using a Gaussian Radial Basis function kernel and its hyperparameters are optimized using Bayesian optimization. Results obtained for the IEEE 14-bus test system demonstrated that the proposed method offers a fast technique for probabilistic transient stability status prediction, with an excellent accuracy. DIgSILENT PowerFactory and MATLAB was utilized for transient stability time-domain simulations (for obtaining training data for support vector machine) and for applying support vector machine, respectively. PubDate: 2022-01-06 DOI: 10.22149/teee.v4i1.144 Issue No:Vol. 4, No. 1 (2022)
Authors:Luís Fabiano Barone Martins, Ricardo Breganon, Uiliam Nelson Lendzion Tomaz Alves, João Paulo Lima Silva Almeida, Elenilson de Vargas Fortes Pages: 25 - 32 Abstract: In this work, a state-space model and control of a DC-DC Buck converter, considering a continuous operating, are presented. A PID controller is considered in the strategy, that considers a low pass filter in the derivative term. The proposed model is validated by comparing it with a switched model. The PID gains are obtained by the Ziegler-Nichols method. In order to improve the system’s performance considering an environment containing high-frequency noises, the modified PID controller is implemented with several configurations. PubDate: 2021-06-27 DOI: 10.22149/teee.v4i1.141 Issue No:Vol. 4, No. 1 (2021)
Authors:Turgay Gucukoglu, Haluk Sarı, Koray Erhan Pages: 7 - 11 Abstract: Today, climate change is a significant effect on population growth, especially in big cities. Transport in metropolitan cities is the most important reason for climate change with the contribution of CO2 pollution that threatens human health and the environment. Electrified transport systems can, therefore, provide a suitable solution to air pollution and health problems. This study investigates the feasibility of applying electric buses to the Metrobus line in Istanbul. Initially, Metrobus line data regarding the number of vehicles, number of stops, route length is gathered from the official Istanbul transportation system to define how much energy is needed for the routes. Then, it is analyzed how to re-charge proposed batteries for the allocation of chargers on the stations where it is applicable. It is observed that the electrification of each line is not possible. PubDate: 2020-02-13 DOI: 10.22149/teee.v4i1.137 Issue No:Vol. 4, No. 1 (2020)
Authors:Vinícius Henrique Farias Brito, José Carlos de Oliveira, Fabricio Parra Santilio Pages: 12 - 17 Abstract: Although there currently exists a wide range of voltage regulators that are commercially available, the search for devices with a simpler physical design remains the focus of research studies. Following this line, an electromagnetic voltage regulator (EVR) arrangement has been proposed. The EVR is constituted of an autotransformer that supplies, via discrete taps, a series transformer that injects voltage for regulating the feeder voltage. Even though its operating principle is shown as being similar to that of other devices on the market, the physical arrangement and operating strategy of EVR show novelties which result in properties such as: economic attractiveness, constructive simplicity, and operational reliability. Moreover, when installing voltage regulators, efficacy studies must be carried out to optimize equipment design. In this context, this paper aims at evaluating the factors that influence the effectiveness of the EVR in restoring voltage variations according to the determinations imposed by regulatory agencies. The ultimate goal of this study is to determine the voltage deviation range that the EVR is able to restore. To achieve this goal, a mathematical modeling of the EVR is given and study cases are computationally carried out to investigate its performance when connected to a typical distribution feeder. PubDate: 2020-06-14 DOI: 10.22149/teee.v4i1.138 Issue No:Vol. 4, No. 1 (2020)
Authors:Kinde Anlay Fante, Fetulhak Abdurahman, Mulugeta Tegegn Gemeda Pages: 18 - 24 Abstract: Image quality assessment methods are used in different image processing applications. Among them, image compression and image super-resolution can be mentioned in wireless capsule endoscopy (WCE) applications. The existing image compression algorithms for WCE employ the generalpurpose image quality assessment (IQA) methods to evaluate the quality of the compressed image. Due to the specific nature of the images captured by WCE, the general-purpose IQA methods are not optimal and give less correlated results to that of subjective IQA (visual perception). This paper presents improved image quality assessment techniques for wireless capsule endoscopy applications. The proposed objective IQA methods are obtained by modifying the existing full-reference image quality assessment techniques. The modification is done by excluding the noninformative regions, in endoscopic images, in the computation of IQA metrics. The experimental results demonstrate that the proposed IQA method gives an improved peak signal-tonoise ratio (PSNR) and structural similarity index (SSIM). The proposed image quality assessment methods are more reliable for compressed endoscopic capsule images. PubDate: 2020-10-24 DOI: 10.22149/teee.v4i1.139 Issue No:Vol. 4, No. 1 (2020)
Authors:Murat Kubilay Ozguc, Eymen Ipek, Kadir Aras, Koray Erhan Pages: 1 - 6 Abstract: Electric vehicles (EV) have brought promising technologies for future mobility solutions. As one of the key components of EVs, battery systems have fundamental functions which disconnect the battery during parking and in case of failure. To provide a safe system, specialized high voltage (HV) electromechanical switches are used to perform these major functions such as switch on, switch off or pre-charging. Due to these components can be easily damaged, expensive, heavy and bulky, a solution based on pure semiconductors may be desired to accomplish these operations. Many studies were exhibited on EV battery systems regarding developing solid-state systems for HV switchgear. Developing technology on semiconductor devices allows to make a safety concept based on only solidstate components. This study presents a comprehensive analysis off pre-charge sequences between conventional and semiconductor switchgear to be used in electric vehicle battery systems. Spice simulations are presented to investigate advantages and drawbacks of these systems. PubDate: 2019-12-25 DOI: 10.22149/teee.v4i1.136 Issue No:Vol. 4, No. 1 (2019)
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