Fleksibilnost elektroenergetskih sustava

Modern power systems rely on power generation from renewable sources, predominantly from wind and solar. However, the intermittency and variability of these sources require additional power system flexibility. Due to retirement of conventional thermal generation, the need for flexibility is increased, while the flexible resources are reduced. Thus, new flexibility resources are sought. This paper examines real-world examples of the increased flexibility requirements, identifies the new sources of flexibility in the form of batteries and demand response, presents relevant mathematical models, and provides guidelines on future research needs in this area.Moderni elektroenergetski sustavi oslanjaju se na proizvodnju električne energije iz obnovljivih izvora energije, prvenstveno vjetra i Sunca. Međutim, nepravilnost i promjenjivost njihove proizvodnje električne energije uzrokuje povećane zahtjeve za fleksibilnošću sustava. Nadalje, uslijed prestanka rada konvencionalnih termalnih elektrana, koje su i same bile izvor fleksibilnosti, nedostatak iste sve je više izražen. Stoga su potrebni novi izvori fleksibilnosti. Članak izučava stvarne primjere povećanih zahtijeva za fleksibilnošću, identificira nove izvore fleksibilnosti (baterije i odaziv potrošnje), te predstavlja relevantne matematičke modele i daje preporuke za buduća istraživanja u ovom području

PHASE SHIFTING AUTOTRANSFORMER, TRANSMISSION SWITCHING AND BATTERY ENERGY STORAGE SYSTEMS TO ENSURE N-1 CRITERION OF STABILITY

Since the portion of non-dispatchable renewable generators in the system is increasing, several challenges to the safety and stability of the power system have arisen. The focus of this paper is analyzing local congestion effects in the system by using three distinct methods: phase shifting autotransformer, transmission switching and battery energy storage system. This work includes a review of the congestion management techniques and the results of simulations that utilize phase shifting autotransformer to reduce power flows in the network, and transmission switching and battery energy storage system in order to ensure N-1 stability criterion in case of malfunction of the integrated autotransformer. Power system is modelled and simulated using Power Transmission System Planning Software, a software tool for electric transmission system analysis and planning. Results of Z. Zbunjak, H. Bašić, H. Pandžić, I. Kuzle, Phase shifting autotransformer, transmission switching and battery energy storage systems to ensure n-1 criterion of stability, Journal of Energy, vol. 64 (2015) Special Issue, p. 285-298 simulations are presented, a thorough analysis of the results is performed and justification of investments in proposed methods is elaborated

PHASE SHIFTING AUTOTRANSFORMER, TRANSMISSION SWITCHING AND BATTERY ENERGY STORAGE SYSTEMS TO ENSURE N-1 CRITERION OF STABILITY

Since the portion of non-dispatchable renewable generators in the system is increasing, several challenges to the safety and stability of the power system have arisen. The focus of this paper is analyzing local congestion effects in the system by using three distinct methods: phase shifting autotransformer, transmission switching and battery energy storage system. This work includes a review of the congestion management techniques and the results of simulations that utilize phase shifting autotransformer to reduce power flows in the network, and transmission switching and battery energy storage system in order to ensure N-1 stability criterion in case of malfunction of the integrated autotransformer. Power system is modelled and simulated using Power Transmission System Planning Software, a software tool for electric transmission system analysis and planning. Results of Z. Zbunjak, H. Bašić, H. Pandžić, I. Kuzle, Phase shifting autotransformer, transmission switching and battery energy storage systems to ensure n-1 criterion of stability, Journal of Energy, vol. 64 (2015) Special Issue, p. 285-298 simulations are presented, a thorough analysis of the results is performed and justification of investments in proposed methods is elaborated

Hydro generating units maintenance scheduling using Benders decomposition

Pravovremeno održavanje proizvodnih postrojenja od iznimne je važnosti za pouzdan i siguran pogon elektroenergetskog sustava. U uvjetima liberaliziranog tržišta električne energije ekonomski aspekti, orijentirani na najveću moguću dobit, moraju biti zadovoljeni. S druge strane, i tehnički aspekti, kojima je cilj održati elektroenergetski sustav iznad željenih granica sigurnosti i pouzdanosti, odnosno koji su protivni ekonomskim ciljevima, također moraju biti zadovoljeni. Stoga se dva suprotna gledišta sukobljavaju u svrhu pronalaska optimalnog rješenja koje će zadovoljiti sve tehničke kriterije i investitora u ekonomskom pogledu. U radu se obrađuje problem pronalaženja optimalnog rasporeda održavanja hidrogeneratora. U tu svrhu se koristi metoda matematičkog programiranja – Bendersova dekompozicija. Nakon kratkog opisa matematičke metode, iznesena je primjena Bendersove dekompozicije na tri hrvatske hidroelektrane u nizu na rijeci Dravi.Maintenance of the power generating facilities in due time is essential for reliable and secure operation of the electric power system. In liberalized electricity market the economical aspects, pointed to the greatest possible revenue, have to be satisfied. On the other hand, technical aspects, which keep the power system above the desired level of safety and reliability, i.e. which are opposed to economical aspects, have to be satisfied as well. Therefore, these two opponent standpoints have to be confronted in order to provide optimal solution which will comply with the strict technical limitations, and which will meet investor\u27s economical requirements. This paper addresses the problem of obtaining the optimal maintenance schedule of hydro generating units. For this purpose, the paper discusses the mathematical programming method – Benders decomposition. After a brief description of the mathematical method, the application of the Benders decomposition on three Croatian hydroelectric power plants in a cascade on the Drava River is carried out

Development of a LabVIEW - Based Data Logging and Monitoring Application for a Photovoltaic Power Plant at FER

The purpose of this paper is to implement an application in LabVIEW programming language which logs the measurements from photovoltaic (PV) inverters. The application’s communication module is connected to the inverters of the PVs via the Modbus TCP/IP protocol and collects the me-asurements of appropriate process quantities, such as the active power, the total electricity produced, the panel temperature, the insolation, the air temperature, etc. Furthermore, all the collected measurements are saved on a 15-minute basis in separate csv files for each day. Additionally, a graphical user interface (GUI) is developed, where the collected measurements from the PV are displayed. The PV for which the application is deve-loped is located on the roof of the building B of the University of Zagreb Faculty of Electrical Engineering and Computing (FER)

Electric vehicle charging infrastructure in Croatia – First-hand experiences and recommendations for future development

One of the most serious obstacles to massive deployment of electric vehicles is insufficient and cumbersome charging infrastructure. Both the number of charging points and their power capacity are often insufficient. On top of that, this new technology often suffers from many issues related to insufficient testing, immaturity and irregular handling. This paper summarizes the issues with the electric vehicle charging infrastructure and describes first-hand experiences with long-range electric vehicle trips originating from Zagreb, Croatia, during 2022. Issues with the charging points locations, power and availability are assessed. Based on these experiences, the paper provides some thoughts on the possible directions of the further development of the electric vehicle charging infrastructure in Croatia

HANDS-ON EXPERIENCE WITH POWER SYSTEMS LABORATORY UPGRADE

This paper addresses the challenges of developing a modern power system laboratory at the Faculty of Electrical Engineering and Computing, University of Zagreb. Focused on problem-based learning, the laboratory, developed together by professors and students, is a key to practical teaching of power system design, analysis and control

HANDS-ON EXPERIENCE WITH POWER SYSTEMS LABORATORY UPGRADE

This paper addresses the challenges of developing a modern power system laboratory at the Faculty of Electrical Engineering and Computing, University of Zagreb. Focused on problem-based learning, the laboratory, developed together by professors and students, is a key to practical teaching of power system design, analysis and control