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An approach for the integration of renewable distributed generation in hybrid DC/AC microgrids
(Pergamon-Elsevier Science Ltd, 2013) Karabiber, Abdulkerim; Keles, Cemal; Kaygusuz, Asim; Alagoz, B. Baykant
This paper presents an investigation of a hybrid DC/AC integration paradigm to establish microgrids (MGs) by using a conventional three-phase local power delivery system. This approach adds an additional DC power line to the local power distribution system in order to collect energy generated by distributed domestic renewable sources. The local renewable distributed generation (DG) works in conjunction with the conventional grid utility to reduce the power draw from the grid. Researchers designed an energy conversion station to mix energy from the local DGs with energy from the grid utility. This approach, therefore, uses a continuous energy mixing strategy for DC integration of local generation and grid energy to supply energy to MG consumers via the conventional three-phase power distribution system. Thus, local distributed renewable generators do not have to contend with AC integration problems, such as AC stability and line synchronization. This approach can facilitate the transformation of conventional local power distribution systems into reliable MGs in an affordable way for stakeholders and it is a step towards construction of future smart grids. (C) 2012 Elsevier Ltd. All rights reserved.
Communication Opportunities in Smart Grids
(Ieee, 2015) Keles, Cemal; Kaygusuz, Asim
The studies concentrate on the new generation electric power systems called smart grid for solution of energy management issues. An essential characteristic of the smart grid is the integration of efficient, reliable and secure communication networks to manage the complex power systems. In this paper, the communication architectures in the power systems, including the communication technologies, network requirements, advantages and application challenges are studied. This study summarizes the current state of the communication networks in the smart grid.
Design of Fractional-Order PI Controllers for Disturbance Rejection Using RDR Measure
(Ieee, 2014) Deniz, Furkan Nur; Alagoz, Baris Baykant; Keles, Cemal; Tan, Nusret
Parameter uncertainties and unpredictable environmental disturbances reduce control performance of real control systems. For a robust control performance, stability and disturbance rejection are two main concerns that should be addressed in practical controller design problems. This paper presents an analysis to deal with system stability and disturbance rejection control for fractional-order PI (FOPI) controllers. Stability Boundary Locus (SBL) is calculated for an example with FOPI control system and Reference to Disturbance Rate (RDR) performance is investigated for the chosen stable FOPI designs from the stability region obtained using SBL. MATLAB/Simulink simulation examples are used to demonstrate stable and Disturbance Rejection Control (DRC) of FOPI control systems and presents comparisons for various designs of FOPI controllers.
Disturbance rejection performance analyses of closed loop control systems by reference to disturbance ratio
(Elsevier Science Inc, 2015) Alagoz, Bans Baykant; Deniz, Furkan Nur; Keles, Cemal; Tan, Nusret
This study investigates disturbance rejection capacity of closed loop control systems by means of reference to disturbance ratio (RDR). The RDR analysis calculates the ratio of reference signal energy to disturbance signal energy at the system output and provides a quantitative evaluation of disturbance rejection performance of control systems on the bases of communication channel limitations. Essentially, RDR provides a straightforward analytical method for the comparison and improvement of implicit disturbance rejection capacity of closed loop control systems. Theoretical analyses demonstrate us that RDR of the negative feedback closed loop control systems are determined by energy spectral density of controller transfer function. In this manner, authors derived design criteria for specifications of disturbance rejection performances of PID and fractional order PID (FOPID) controller structures. RDR spectra are calculated for investigation of frequency dependence of disturbance rejection capacity and spectral RDR analyses are carried out for PID and FOPID controllers. For the validation of theoretical results, simulation examples are presented. (C) 2014 ISA. Published by Elsevier Ltd. All rights reserved.
Frequency Deviation Indicators for Estimation of Energy Balance State in Smart AC Grids
(Ieee, 2016) Alagoz, Baris Baykant; Keles, Cemal; Kaygusuz, Asim; Akcin, Murat
Due to increasing intermittent renewable energy utilization in smart grids, smart management of energy balance is becoming major concern of research studies. In the case of highly volatile generation and demand conditions, it is very important to estimate instant energy balance state of electricity grid to preserve energy balance automatically and avoid from the cases of generation deficiency and overloading. The utility frequency deviation is commonly used to restore power imbalance in AC grids. This study gives a discussion on the utilization of frequency deviation of AC power system as an indicator of energy balance state in smart grids. We consider two approaches to estimate instant AC frequency deviation of power systems under serious harmonic and noise conditions. The first one is based on frequency to amplitude conversion technique, which use band-pass ramp filtering of AC signal. The other method is based on the sinusoidal to pulse waveform conversion, and it uses measurement of pulse periods of the resulting square waveforms. We compare these two methods and discuss their advantages and disadvantages to generate a balance error signal for smart grid applications. A brief discussion on application of these signals for smart grid energy management is given.
Implementation of Demand Side Load Management by Domestic Load Shedding Algorithm for Conventional Electricity Meters
(Ieee, 2019) Keles, Cemal; Yigit, Yusuf
Load management, an application of demand side management, plays a key role in the implementation of smart grid applications. Specifically, demand side load management (DSLM) applications improve the grid flexibility. Recent developments in power electronics, communication and automation technologies facilitate implementation of domestic load management methods. This study suggests a residential load shedding method to perform DSLM under time-of-use (ToU) tariff in real system. To perform this operation, a circuit connected to the output of conventional electricity meters is designed. Arduino has been used as microcontroller system in this circuit and the developed load shedding algorithm is embedded in microcontroller. The relay system also performs the load shedding algorithm by controlling the lines at the output of the electricity meter with the signals generated by the microcontroller. Thus, demand side load management applications, which are an important part of smart grid applications, are realized with the designed circuit and without any electricity meter change.
Implicit disturbance rejection performance analysis of closed loop control systems according to communication channel limitations
(Inst Engineering Technology-Iet, 2015) Alagoz, Baris Baykant; Tan, Nusret; Deniz, Furkan Nur; Keles, Cemal
This study investigates limits of implicit disturbance rejection capacity of negative feedback control systems on the basis of communication channel limitations. Disturbance rejection performance of closed loop control structure is evaluated by using reference to disturbance ratio (RDR). Boundaries of RDR performance for stable control system are investigated by using stability boundary locus analyses. For computer-aided system design problems, a graphical design method for disturbance rejection PID control system is presented and illustrative examples are shown. Numerical examples show that disturbance rejection control with improved step response performance is obtainable by two-degree-of-freedom design combining high gain PID control and input prefiltering.
Lightning surge analysis of Faraday cage using alternative transient program-electromagnetic transients program
(Inst Engineering Technology-Iet, 2016) Mamis, Mehmet Salih; Keles, Cemal; Arkan, Muslum; Kaya, Ramazan
Lightning surge analysis of protective structures is significant for the design of system. However, simulation models are limited. In this study, a Faraday cage with four air terminals and 2 x 6 grounding rods built to protect a switchyard control building in a 380 kV substation is simulated in alternative transient program for the analysis of lightning surges. Distributed line modelling is used for cage conductors. Down conductors are represented by considering non-uniform variation of the conductor parameters. Current waveforms through the system and voltages at some critical points after a lightning stroke are computed. The traditional lightning parameters needed in structural protection such as lightning peak current, maximum current derivative, current rise time and current duration are determined. The effects of mesh size and some system parameters such as grounding resistance and lightning surge impedance are investigated.
Modeling of the Particle Build-Up Evolution on a Single-Wire Magnetic Capture from Axial Stream Flow
(Mdpi, 2022) Bilgili, Hatice; Keles, Cemal; Abbasov, Teymuraz
The kinetic equation of the accumulation of magnetic particles from axial flow on a magnetized ferromagnetic wire in an external homogeneous magnetic field has been developed in this study. A new differential equation of the evolution of the accumulation radius over time, which considers both the capture and the detachment of the particles in the accumulation profile on the wire, has been formulated. The evolution of the radius of the accumulation profile over time was obtained from both the differential kinetic equation based on population theory and from the stochastic Fokker-Planck equation. In the limit approach (t & RARR;& INFIN;), it was observed that the expressions of the saturation radius of the accumulation radius on the magnetized wire of the particles obtained from both models were the same. It is emphasized that the obtained results are valid for both the initial and steady-state build-up of the particle capture process. These results were compared with the experimental results from the literature, and it was observed that the theoretical and experimental results were in good agreement. The effects of both capture and detachment events on the accumulation of particles on the magnetized wire were evaluated.
Multi-source Energy Mixing by Time Rate Multiple PWM for Microgrids
(Ieee, 2016) Keles, Cemal; Kaygusuz, Asim; Alagoz, Baris Baykant
Smart grid applications aims to employ many optimization and artificial intelligence methods for optimal energy management. Results of these algorithms need to be implemented by power systems in practice. This study presents Time Rate Multiple Pulse Width Modulation (TRM-PWM) methods for multi-source energy mixing for DC microgrids, which is integrating several renewable energy resources. In the paper, we implement TRM-PWM multi- source energy mixer component for integration of energy flow coming from solar and wind energy systems, battery system and grid in MATLAB simulink. Simulation results show that proposed energy mixer component can adjust rate of energy mixing from different sources. By using this component, optimal energy mixing, which can be adjusted by optimization and artificial intelligence methods, can be realized in smart grid applications.
Multi-Source Energy Mixing for Renewable Energy Microgrids by Particle Swarm Optimization
(Ieee, 2017) Keles, Cemal; Alagoz, Baris Baykant; Kaygusuz, Asim
Distributed intelligence is one of the prominent prospects of future smart grids besides distributed generation, distributed storage and demand side load management. This study illustrates utilization of particle swarm optimization (PSO) method for cost-efficient energy management in multi-source renewable energy microgrids. PSO algorithm is used to find out optimal energy mixing rates that can minimize daily energy cost of a renewable microgrids under energy balance and antiislanding constraints. The optimal energy mixing rates can be used by multi-pulse width modulation (M-PWM) energy mixer units. In our numerical analyses, we consider a multi-source renewable energy grid scenario that includes solar energy system, wind energy system, battery system and utility grid connection. We assume that variable energy pricing is used in utility grid to control energy dispatches between microgrids. This numerical analysis shows that the proposed scheme can adjust energy mixing rates for M-PWM energy mixers to achieve the cost-efficient and energy balanced management of microgrid under varying generation, demand and price conditions. The proposed method illustrates an implementation of distributed intelligence in smart grids.
A Note On Demand Side Load Management by Maximum Power Limited Load Shedding Algorithm For Smart Grids
(Ieee, 2015) Keles, Cemal; Alagoz, Baris Baykant; Kaygusuz, Asim
Demand side load management (DSLM) applications improve grid flexibility and support intermittent renewable energy utilization. In this study, we discuss role of power limited load shedding algorithm for DSLM applications in domestic scales. By using this algorithm, domestic power consumption is limited with respect to dynamic electricity price signal and renewable energy generation level by switching off the low prior home electronics appliances (HEAs). The proposed load shedding scheme performs depending on power requirements of HEAs and their user priority presetting. In this study, power limited load shedding algorithm is improved to consider operation modes, which are grid mode, islanded mode and grid+renewable energy (RE) mode and effects of the proposed scheme on domestic consumption is discussed by using simulation results.
Opportunities for Energy Efficiency in Smart Cities
(Ieee, 2016) Akcin, Murat; Kaygusuz, Asim; Karabiber, Abdulkerim; Alagoz, Serkan; Alagoz, Baris Baykant; Keles, Cemal
Rapid migration from rural to urban areas leads to the emergence of urbanization and sustainability problems. Management and monitoring of resources and infrastructures are getting more important today in crowded cities. Energy consumption is increasing with the growing population and intensified in highly populated parts of cities. This increased energy consumption results in high energy demand as well as the production of more pollutants and heat in these city parts. The management of pollution and heat problems leads to an additional energy demand. Therefore, energy efficiency is becoming central challenge for urban life similar to energy efficient structuring of living organisms. Practically, all activities arranging city life require energy. For instance, job activities, transportation, security, climate, catering, entertainment, commerce etc. In this study, we review active and passive approaches, which can be utilized for improvement of energy efficiency and thus sustainability of urbanization in today's cities. We give a discussion to present a vision for future smart cities in term of improvement of energy utilization and efficiency, and relieve of environmental issues. These approaches can be helpful for future cities for relieving issues originating from population increase.
Possible Contributions of Smart Grids to Regional Development of Countries
(Ieee, 2018) Kaygusuz, Asim; Tuttokmagi, Ozge; Keles, Cemal; Alagoz, Baris Baykant
Although smart grid concept has recently become a subject of academic studies; impacts of this concept appear in many areas of engineering. Today, the smart grid concept involves many subjects from the efficient use of electrical energy resources to the planned and programmed consumption of energy, from the integration of distributed renewable energy sources into the system to the domestic productive consumers (prosumers), which are much related to local or regional development. Smart grid concept, which emerges a product of interdisciplinary studies ranging to many fields of engineering such as power systems, control, artificial intelligence and communication, can be briefly viewed as a development process towards the internet of energy. Especially in recent years, the decrease in reserves of fossil-fueled energy sources has led researchers to find out new energy sources, more efficient and ecological production and distribution methods. In these studies, the energy sources, which are renewable, sustainable, and economical have become major priorities due to reducing carbon emissions. However, the scope of smart grid studies has been continuously enriched and it has begun to include the fundamental components of production-centered sustainable development models, which are the providing of low-cost production supplies, continuity of these supplies, efficiency in production and consumption, generation based on renewable or recyclable resources, and applications of ecological generation and consumption methods. In this context, the positive effects of smart grids on the regional development are expected to occur in the following topics: Smart city applications, intelligent transportation, renewable and local energy generation, smart homes and building concepts, energy efficient cities, control of carbon footprint, automated electricity, gas, water and waste networks, loss and leakage control, application of demand side energy management system to reduce power consumption, self-healing electricity distribution, smart energy pricing, smart energy storage are some emergent topics that can contribute to sustainable regional development models. Because, modern grid components developed within the scope of smart grid are expected to support sustainable production models via smart energy management and increasing efficiency, reducing the energy costs, improving energy continuity. In this study, a projection for possible contributions of smart grid concept with its continuously expanding scope to the sustainable regional development is discussed under several major headings.
Power Converters Modeling in Matlab/Simulink for Microgrid Simulations
(Ieee, 2016) Karabiber, Abdulkerim; Keles, Cemal; Kaygusuz, Asim; Alagoz, Bans Baykant; Akcin, Murat
Smart grid is a developing field for energy researchers. It offers technological improvements to have more controllable, reliable and sustainable power grids. Especially, the decreasing trend of fuels has pressurized to pay researchers' attention to renewable energy sources such as solar systems and wind turbines. The renewable energy sources generate electric power in different characteristics. Therefore, power converters are needed to integrate these sources in a grid to provide power flows among the sources and loads. This study presents Matlab/Simulink models of power converters and dynamic load structure, which are useful for smart grid simulations. These simulations can be used for research and educational purposes. Characteristic parameters of the models are suitable for existing devices. For power converters, Pulse-width Modulation technique is utilized that it is widely used in industry. The designed power converters and dynamic load models are tested in a microgrid application. The simulation results show that the designed power components are useful for smart grid simulation studies.
Power regulated DC/DC driver design by hierarchical control
(Tubıtak scıentıfıc & technıcal research councıl turkey, ataturk bulvarı no 221, kavaklıdere, ankara, 00000, turkey, 2016) Alagoz, Baris Baykant; Keles, Cemal; Kaygusuz, Asim; Kaplan, Yusuf; Karabiber, Abdulkerim
As a result of advances in solid-state power electronics, DC power distribution has found widespread usage due to its advantages. DC/DC converters, which are mainly used for voltage regulation, are fundamental components of DC power distribution systems. This paper presents a peak power controlled DC/DC converter design based on a two layer hierarchical closed-loop control strategy for active DC power management. The proposed DC/DC converter design, called a power regulated DC/DC driver, limits output power according to current-voltage characteristic of a modified sigmoid function and it allows more secure and controllable power delivery in DC distribution buses. As a design example, we illustrate use of these DC/DC drivers in an active power distribution management application for electric vehicles. The MATLAB/Simulink simulation environment was used for the design and simulation of the proposed DC power distribution system. Simulation results indicate that the active power distribution management system composed of the power regulated DC/DC driver nodes can allow more reliable power distribution for electric vehicles.
Renewable energy integration for smart sites
(Elsevier Science Sa, 2013) Kaygusuz, Asim; Keles, Cemal; Alagoz, Baris Baykant; Karabiber, Abdulkerim
Use of distributed renewable energy sources for domestic energy consumption will increase in the near future, due to its advantages as being clean and infinite energy generation possibility. This trend allows more efficient energy consumption because of reducing transmission loses and dependence of domestic appliances to grid distribution. This study investigates potentials of a smart site concept based on domestic renewable energy generation. The study addresses site scale integration of hybrid renewable sources and grid energies as well as investigates possible advantages of the use of hybrid renewable energy systems based on solar and wind power. A continuous energy mixing strategy is used for DC integration of hybrid renewable energy (wind + solar) and the grid energy to meet site power demand. The proposed case study demonstrates that the smart site with hybrid renewable sources considerably reduces energy dependence of the house appliances to the grid which in turn presents a feasible solution for implementation of distributed generation provision for future smart grids. (C) 2013 Elsevier BM. All rights reserved.
A smart building power management concept: Smart socket applications with DC distribution
(Elsevier Sci Ltd, 2015) Keles, Cemal; Karabiber, Abdulkerim; Akcin, Murat; Kaygusuz, Asim; Alagoz, Bads Baykant; Gul, Ozan
Recent developments in power electronics increase DC bus utilization in electrical distribution systems due to its numerous advantages compared to AC distribution system in term of energy efficiency, safety, electromagnetic compatibility and renewable energy integration. This study presents a power management system concept based on domestic DC distribution with smart sockets for future smart houses. Energy efficient smart buildings are possible by integrating smart meter, smart sockets, domestic renewable energy generation and energy storage systems for integrated energy management, and this integrated system supports demand side load management, distributed generation and distributed storage provisions of future smart grids. Coming era of smart grids has implications for domestic DC distribution concepts with smarts sockets. Paper describes use of smart DC sockets as an integral part of building power management automation and presents a load shedding algorithm for plug load control for buildings. Simulations show performance of the proposed system components. (C) 2014 Elsevier Ltd. All rights reserved.
Towards Energy Webs: Hierarchical Tree Topology for Future Smart Grids
(Ieee, 2015) Alagoz, Baris Baykant; Keles, Cemal; Kaygusuz, Asim
Digital era of technology transforms communication and information systems in a revolutionarily way, which makes our applications more integrated, more connected and smarter. However, conventional energy systems do not adequately benefit from opportunities of digital revolution, yet. Interdisciplinary works in the scope of smart grids grow our expectations from electricity grids such as increase of domestic renewable energy utilization, application of active load management in residences. One of challenging tasks for the digital era of energy systems is the transforming traditional static consumer concept to the active user concept, namely prosumers, who exhibit renewable energy generation potential and share own generation by the energy webs. A major problem for the implementation of practical energy webs is the management of energy balance in grid due to the fact that prosumers lead to the high uncertainty and volatility in generation and demand. Authors suggest that hierarchical tree topology as grid architecture can facilitate energy balance management and energy dispatching mechanisms for future energy webs. Because, acyclic structure and scalability of hierarchical tree (HT) topology present advantages of defining family relationships on the node hierarchy of grids. This property can improve accessibility and controllability of the smart grid and facilitates energy dispatches on the grid. This study gives a discussion on advantages of HT topology for smart grid applications and projects for some opportunities on the way of future energy webs.
Transmission lines fault location using transient signal spectrum
(Elsevier Sci Ltd, 2013) Mamis, Mehmet Salih; Arkan, Muslum; Keles, Cemal
This paper proposes a method for fault location on transmission lines, which is based on time to frequency domain transformation of transient signals of the fault instant measured at one end. Fast Fourier Transform (FFT) is used for time to frequency domain transformation and frequency of the first fault generated harmonic is utilised for determination of the fault location using the travelling wave theory of the transmission line. The accuracy of the method has been tested using the simulations carried out in Alternative Transients Program (ATP/EMTP) with frequency-dependent distributed parameter transmission line model by considering several cases and various types of faults, different values of fault resistance and phase angle at fault instant. The method has good accuracy and the simulation results show that the accuracy of the method is insensitive to the fault resistance and phase angle of the fault instant. Reactive elements may affect the resolution but, it can be removed by applying the correction procedure proposed. (C) 2013 Elsevier Ltd. All rights reserved.

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