Elektrik-Elektronik Mühendisliği Bölümü Makale Koleksiyonuhttps://hdl.handle.net/20.500.12418/5932024-03-28T20:45:16Z2024-03-28T20:45:16ZTap Staggering Analysis and Effects on the Adaptive Protection System in Networks With Renewable Energy SourcesKasap, HakanPürlü, MikailEmre Türkay, BelginGanjavi, Rezahttps://hdl.handle.net/20.500.12418/147462024-03-06T21:47:28Z0005-01-01T00:00:00ZTap Staggering Analysis and Effects on the Adaptive Protection System in Networks With Renewable Energy Sources
Kasap, Hakan; Pürlü, Mikail; Emre Türkay, Belgin; Ganjavi, Reza
Increasing the penetration of renewable energy sources as distributed generation in modern power grids presents several challenges, including voltage level issues and protection system failures resulting from bidirectional power flow and changing network dynamics. Voltage limit violations could potentially damage the utility equipment and lead to power quality problems. Innovative Volt/VAr control methods, such as tap staggering, can be used to overcome these problems. Tap staggering utilizes circulating current between parallel transformers to provide reactive power absorption from the network. However, the absorption of reactive power by the primary substation using tap staggering poses a potential risk to the protection system, particularly the Directional Overcurrent protection scheme with Load Blinder. This could lead to failures or nuisance trips during normal load conditions. In this study, a real power system is modeled using real data in PSS CAPE with 120 scenarios generated through tap staggering application, all based on 24-hour demand/wind generation data. The Tap Staggering Macro and Adaptation Protection Macro were developed for the purpose of analyzing these scenarios. The study demonstrates that tap staggering effectively mitigates overvoltage issues on the transmission system by absorbing reactive power. Although
there is an increase in active power losses when tap staggering level is increased on the parallel transformers, the power loss remains within reasonable limits. Despite its benefits, tap staggering has been found to affect the Directional Overcurrent with Load Blinder protection scheme, limiting power transfer generated through wind turbines in the distribution network. This results in changes to the protection scheme’s Directional Overcurrent Pickup, Load Blinder Resistance, and Load Blinder Alpha parameters, requiring adaptation in all scenarios. After adaptation, the protection system operates reliably, guaranteeing efficient and unrestricted transmission of distributed generation power to the grid.
0005-01-01T00:00:00ZNext-Generation Application-Based Artificial Intelligence in Modeling and Estimation for Ni/n-GaAs/In Schottky Barrier DiodeDoğan, HülyaKoçkanat,Serdarhttps://hdl.handle.net/20.500.12418/147272024-03-06T21:47:28Z0014-01-01T00:00:00ZNext-Generation Application-Based Artificial Intelligence in Modeling and Estimation for Ni/n-GaAs/In Schottky Barrier Diode
Doğan, Hülya; Koçkanat,Serdar
Herein, for Ni/n-GaAs/In Schottky barrier diode, experimental measurement, modeling, data generation from the model, and parameter estimation processes are simultaneously carried out. In the experimental step, Ni/n-GaAs/In Schottky barrier diodes are fabricated and annealed from the temperature of 200 °C up to 600 °C with 100 °C steps. Current values are recorded by applying voltage to the diode contacts from −1 V up to 0.5 V. In the modeling step, 1503 experimental current–voltage data are used for 19 different regression models. For Adaptive Neuro Fuzzy System (ANFIS), when root mean square error, mean square error, mean absolute error, and coefficient of determination are calculated 6.0341e-07, 3.6410e-13, 2.3873e-07, and 0.9999 for training, they are obtained 5.8904e-07, 3.4697e-13, 2.3083e-07, and 0.9999 for testing. In the estimation step, the values of electrical parameters are estimated by using Mayfly algorithm. Estimations are performed for all annealing temperatures. In addition, current–voltage data for the annealing temperature of 350 °C are produced by the ANFIS model. Thus, a new-generation artificial intelligence application, that includes measurement, modeling, and estimation for the Ni/n-GaAs/In Schottky barrier diode with varying annealing temperatures, is realized and a new perspective is provided to researchers and practitioners.
0014-01-01T00:00:00ZFDTD-based SAR calculation of a wearable antenna for wireless body area network devicesKaburcuk, FatihSavcı, Hüseyin Şerifhttps://hdl.handle.net/20.500.12418/145222024-03-01T21:47:20Z2023-01-01T00:00:00ZFDTD-based SAR calculation of a wearable antenna for wireless body area network devices
Kaburcuk, Fatih; Savcı, Hüseyin Şerif
Wireless-connected wearable electronics are finding extensive usage for diagnostic and therapeutic purposes after the globally spread pandemic disease of COVID-19. Although they are undoubtedly helpful for keeping physical distance, their health effects are still under investigation from different aspects and are still a concern for the end-users. In this study, a custom M-shaped wearable antenna covering the wireless body area network and wireless local area network frequencies is designed, built, and measured. A beret cap made from a 2 mm thick textile is used as a substrate. The specific absorption rate (SAR) in a realistic human-head model due to electromagnetic energy produced by the antenna is evaluated using the finite-difference time-domain method. The SAR distributions for 1-g and 10-g tissues are calculated at 2.4 and 5.8 GHz. It is shown that the obtained maximum SAR values for 1-g and 10-g tissues at each frequency of interest were less than the limits determined by IEEE RF exposure guidelines and standards.
2023-01-01T00:00:00ZEffect of Change of Reluctance Launcher Parameters on Projectile VelocitySari, Vekilhttps://hdl.handle.net/20.500.12418/142432024-01-10T06:22:15Z2023-01-01T00:00:00ZEffect of Change of Reluctance Launcher Parameters on Projectile Velocity
Sari, Vekil
In this study, it is aimed to increase the projectile velocity by changing some parameters of the reluctance launcher. Studied parameters are the initial position of the projectile, the coating of the coil with ferrite, the coil length and the barrel outer diameter. A 3D Maxwell model of the reluctance launcher was generated to examine the effect of the change of these parameters on the projectile velocity. After the 3D model of the launcher was generated, analysis was done for each parameter. During the analysis for a parameter, the other parameters were kept constant. As a result of the analysis of the projectile position, it was determined that the projectile velocity is the highest when the projectile position is −2. It has been determined that the velocity of the projectile increases if the coil is coated with ferrite. It has been determined that the projectile velocity is the highest when the coil length is 7 cm. It has been determined that the highest projectile velocity is obtained when the barrel outer diameter is 18 mm. Using these results, the Maxwell model of the improved launcher was generated. The projectile velocity in the Maxwell model of the initial launcher is 19.24 m/sec. The projectile velocity of the improved launcher in the Maxwell model is 25.8 m/sec. By improving the launcher, a velocity increase of 34.09% was achieved. Later, this launcher was built and the parameters were investigated experimentally. In the experimental work, the projectile velocity of the initial launcher was measured as 19.11 m/sec, and the projectile velocity of the improved launcher was measured as 24.9 m/sec. As a result of the experimental work, a velocity increase of 30.29% was obtained by improving the launcher.
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