Browsing by Author "Özdemir, Aydoğan"

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Citation Count: 0
Akıllı Şebekeler Ve Akıllı Toplum İçin Gelişmiş Evrimsel Hesaplamalar
(2020) Özdemir, Aydoğan; Ahmadı, Bahman; Ceylan, Oğuzhan; Younesı, Soheıl
Elektrik ve enformasyon altyapılarının birleşimi ile oluşan akıllı şebekelerin (AŞ), geleceğin elektrik üretim, iletim ve dağıtım sistemlerinin, daha az karbon salınımı ile daha ekonomik ve güvenilir bir hizmet sağlamasında kilit rol oynaması beklenmektedir. Diğer yandan, dağılmış enerji kaynaklarının (DEK) yaygın bir şekilde elektrik dağıtım sistemlerine bağlanması ve serbestleştirme olguları, yeni işletim ve kontrol felsefeleri geliştirilmesini zorunlu kılmıştır. Bu projenin amacı, AŞ?nin belirtilen hesaplama ihtiyacını karşılamak üzere, gelişmiş evrimsel algoritma tabanlı çözümler sunmaktır. Bu kapsamda, iki temel göreve odaklanılması düşünülmüştür. ? Dağıtık enerji ve depolama kaynakları ve talep gelişimi dikkate alınarak dağıtım şebekesi geliştirme ve genişleme planları, ? Dağıtık enerji kaynakları ve depolama birimleri dikkate alınarak bara gerilim profillerinin iyileştirilmesi, yatırım ve işletme giderlerinin minimizasyonu, dağıtım şebeke kayıplarının azaltılması, güvenilirliğin arttırılması, gerilim ve reaktif güç kontrolü, uzun süreli arıza sonrası yeniden yapılandırma ve şebeke restorasyonu. Yukarıda belirtilen problemler, uygun amaç fonksiyonları ile modellenerek birer eniyileme (optimizasyon) problemi olarak ifade edilerek, çeşitli gelişmiş evrimsel algoritmalarla çözülmüşlerdir. Burada önerilen gelişmiş evrimsel hesaplamaların, alışılagelmiş çözüm tekniklerine göre şu temel farklılıkları içermektedir. ? Bu projede henüz daha çok yeni geliştirilen evrimsel algoritmalar ve bunların gelişmiş halleri olup, yerel arama destekleri ile birlikte, hızla ve yeteri doğrulukta çözüm veren tekniklerdir. ? Söz konusu algoritmalar, tüm yarı-optimal çözüm seçeneklerini veren güvenilir çözümler sağlamaktadır. ? Paralel/dağıtık hesaplama teknikleri ve/veya karma (memtic) algoritmalarla birlikte uygulanarak, gelişmiş evrimsel algoritma tabanlı çözümleri gerçekleşmiştir. Geliştirilen algoritmaların performansı, 33 bara, 69 bara ve 141 baralı test sisteminde denenmiş; fakat pandemi dönemi kısıtları nedeniyle BEDAŞ Elektrik şebekesinde uygulaması henüz tamamlanamamıştır.
Citation Count: 2
Branch outage simulation based contingency screening by gravitational search algorithm
(Praise Worthy Prize Srl, 2012) Ceylan, Oğuzhan; Dağ, Hasan; Dağ, Hasan
Power systems contingency analysis is an important issue for electric power system operators. This paper performs branch outage simulation based contingency screening using a bounded network approach. Local constrained optimization problem representing the branch outage phenomena is solved by the gravitational search algorithm. The proposed method is applied to IEEE 14 30 57 and 118 Bus Test systems and its performance from the point of capturing violations is evaluated. In addition false alarms and the computational accuracy of the proposed method are also analyzed by using scattering diagrams. Finally the proposed gravitational search based contingency screening is compared with full AC load flow solutions from the point of computational speed. Copyright (C) 2012 Praise Worthy Prize S.r.l. - All rights reserved.
Citation Count: 12
Comparison of post outage bus voltage magnitudes estimated by harmony search and differential evolution methods
(2009) Ceylan, Oğuzhan; Dağ, Hasan; Dağ, Hasan
Contingency studies are indispensable tools of both the power system planning and operational studies. Real time implementation of operational problems makes necessary the use of high speed computational methods while requiring reasonable accuracies. On the other hand, accuracy of the results and the speed of calculation depend on branch outage modeling as well as solution algorithm used. This paper presents a comparison of post outage bus voltage magnitudes calculated by two meta-heuristic approaches; namely differential evolution (DE) and harmony search (HS) methods. The methods are tested on IEEE 14, IEEE 30, IEEE 57, and IEEE 118 bus test systems and the results are compared both in terms of accuracy and calculation speed.
Citation Count: 2
Double branch outage modeling and simulation: Bounded network approach
(Elsevier Science, 2015) Dağ, Hasan; Ceylan, Oğuzhan; Dağ, Hasan
Energy management system operators perform regular outage simulations in order to ensure secure operation of power systems. AC power flow based outage simulations are not preferred because of insufficient computational speed. Hence several outage models and computational methods providing acceptable accuracy have been developed. On the other hand double branch outages are critical rare events which can result in cascading outages and system collapse. This paper presents a double branch outage model and formulation of the phenomena as a constrained optimization problem. Optimization problem is then solved by using differential evolution method and particle swarm optimization algorithm. The proposed algorithm is applied to IEEE test systems. Computational accuracies of differential evolution based solutions and particle swarm optimization based solutions are discussed for IEEE 30 Bus Test System and IEEE 118 Bus Test System applications. IEEE 14 Bus Test System IEEE 30 Bus Test System IEEE 57 Bus Test System IEEE 118 Bus Test System and IEEE 300 Bus Test System simulation results are compared to AC load flows in terms of computational speed. Finally the performance of the proposed method is analyzed for different outage configurations. (C) 2015 Elsevier Ltd. All rights reserved.
Citation Count: 19
Grey Wolf optimizer for allocation and sizing of distributed renewable generation
(Institute of Electrical and Electronics Engineers Inc., 2019) Ceylan, Oğuzhan; Ceylan, Oğuzhan; Özdemir, Aydoğan
Increasing penetration of distributed energy resources (DERs) have brought operational and control philosophy changes in Smart Grids (SGs). Renewable energy based technologies are becoming more important due to their economic and environmental impacts. Distributed generations (DGs) in the form of small renewable energy resources such as solar photovoltaics (PVs) and Wind Turbines (WTs) are connected in radial distribution networks near to the loads. This paper presents optimal siting and sizing of distributed renewable energy resource to maintain voltage magnitude profiles. Bus voltage magnitude differences for each hour in a day of a distribution system are formulated as an objective function. Three consecutive days are taken into account representing the three seasons of a year. A new nature inspired algorithm Grey Wolf Optimizer (GWO) is used as a solution tool. The proposed formulation is applied to 33 bus and 69 bus radial distribution networks. MATLAB simulations are performed to validate the performance of the approach. Simulation results are discussed and compared with of the several available ones'.
Citation Count: 0
Impacts of Load and Generation Volatilities on the Voltage Profiles Improved by Distributed Energy Resources
(Institute of Electrical and Electronics Engineers Inc., 2020) Ceylan, Oğuzhan; Ceylan, Oğuzhan; Özdemir, Aydoğan
Weather-dependent distributed renewable energy sources such as photovoltaics (PVs) and wind turbines (WT) are increasingly being connected to distribution networks (DNs). Increased penetration of these intermittent sources brought the necessity of using energy storage systems (ESSs) to achieve the intended benefits. This study presents an optimization process to determine optimal numbers, sizes, locations and distributed energy resources (DERs) as well as to determine the optimal operating strategy of ESSs in a distribution network. The objective is to improve the voltage profile and to minimize the installation costs. The proposed multi-objective formulation problem is solved by using ant lion multi-objective optimization algorithm. At the second part of the study, optimal values are tested with monthly extreme distributions and the impacts of load and distributed generation volatilies on the voltage profiles which were determined by Pareto-optimal solution candidates are analysed. Simulations were performed on 33 bus radial distribution system using Matlab. Finally the benefits obtained by the optimal solutions with less risk are compared.
Citation Count: 11
Optimal Allocation Of Multi-Type Distributed Generators For Minimization Of Power Losses In Distribution Systems
(Institute of Electrical and Electronics Engineers Inc., 2019) Ceylan, Oğuzhan; Ceylan, Oğuzhan; Özdemir, Aydoğan
Distributed generation (DG), including photovoltaics (PVs), wind turbines (WTs) are becoming vital for Active Distribution Networks (ADN). Therefore, optimal sizing and allocation of these units can improve voltage profiles and reduce active power losses. This study concentrates on optimal allocation and sizing of two kinds of DG units (PVs and WTs) with 1 MW maximum size limits, due to the regulations in Turkey. The Whale optimization algorithm (WOA) and Grey wolf optimization algorithm (GWO) are used as optimization tools to minimize active power losses of 33 and 69 Bus Test Systems. The performance analysis of the methods are performed through simulations and the numerical results are compared in terms of optimal OF values and convergence characteristics.
Citation Count: 0
Parallel Contingency Analysis Using Differential Evolution Based Solution For Branch Outage Problem
(IEEE, 2010) Dağ, Hasan; Ceylan, Oğuzhan; Özdemir, Aydoğan
Contingency analysis is one of the most fundamental work an electricity management center operator has to perform regularly. If both bus voltage magnitudes and reactive power flowing on the branches during any type of outages are within the acceptable limits the system is called secure. In this paper we solve the contingency problem using a recently developed local constrained optimization based branch outage problem. The optimization problem resulted from the formulation of branch outage is solved by differential evolution method. Using Matlab's parallel computing toolbox contingency analysis for IEEE 300 test system is performed and the results are presented. The study shows that it is straight forward to implement contingency analysis on the Matlab's parallel environment and obtain near linear speedups.
Citation Count: 0
Towards Faster Branch Outage Simulations Using Simulated Annealing and Parallel Programming
(IEEE, 2009) Dağ, Hasan; Ceylan, Oğuzhan; Dağ, Hasan
Contingency studies such as branch outage and generator outage are among important studies of energy management centers operations. Branch outage modeling on the other hand is one of the basic steps of post-outage state estimation of an electrical power system. Real time implementation of the problem brings the necessity of using high speed methods while providing a reasonable accuracy. This paper presents simulated annealing based solution of the branch outage event which is formulated as a local optimization problem. To speed up the solution procedure the distributed computing toolbox of Matlab is used as a parallel programming tool. The results of the proposed method are compared to those of full AC method and are discussed both from the point of accuracy and solution speed.
Citation Count: 8
Voltage Profile Improving and Peak Shaving Using Multi-type Distributed Generators and Battery Energy Storage Systems in Distribution Networks
(Institute of Electrical and Electronics Engineers Inc., 2020) Ceylan, Oğuzhan; Ceylan, Oğuzhan; Özdemir, Aydoğan
Optimal sizing and siting of distributed generation (DG) units play an important role for improving voltage profile and reducing power losses. Moreover, battery energy storage system (BESS) units may help peak shaving. This paper presents a two stage approach, first of which aims optimal DG unit allocation, and second aims to determine optimal location and operation of BESS units. The problem formulation adopted due to the regulations in Turkey that supports DG units (Photovoltaics-PVs and Wind Turbines-WTs) with maximum unit size of 1 MW. A recently developed heuristic optimization method named as Harris hawks optimization (HHO) algorithm is used for obtaining near optimal solutions. We tested the developed model by using 33 and 141 bus distribution test systems.