Fraunhofer-Institut für Angewandte Informationstechnik FIT

Filters

1 1
9
Reset filters

Settings
Now showing 1 - 9 of 9
  • Publication
    Centralized Model Predictive Control for Transient Frequency Control in Islanded Inverter-Based Microgrids
    ( 2023)
    Heins, T.
    ;
    Josevski, M.
    ;
    Gurumurthy, S.
    ;
    Monti, Antonello
    Grid-forming inverters can establish frequency and voltage regulation in autonomous microgrids by themselves without relying on the external grid and as such are significant enablers for the integration of inverter-interfaced renewable energy sources. The most prominent grid-forming strategies, the droop-based techniques, cannot provide an error-free frequency regulation after a step-wise disturbance and thus are completed by the secondary integral action. In this paper, we propose a model predictive control for fast frequency response in an AC, purely inverter-based microgrid operating in islanded mode. The controller acts as a secondary control unit and adjusts the control actions of the underlying droop controllers leading to an error-free frequency transient control. The controller has been designed leveraging the concept of frequency divider - a simple analytical formulation that estimates the frequency at every system bus. The proposed control is successful in providing a fast frequency response, i.e., it assures a system-wide error-free frequency regulation under different operating circumstances including load changes and varying X/R-ratios. Numerical simulations are carried out in the WSCC 9-Bus and IEEE 39-Bus systems to verify the performance of the proposed method during transients and a comparison with respect to the more common secondary frequency control is given.
  • Publication
    A Service Oriented Architecture for the Digitalization and Automation of Distribution Grids
    ( 2022)
    Pau, Marco
    ;
    Mirz, Markus
    ;
    Dinkelbach, Jan
    ;
    McKeever, Padraic
    ;
    Ponci, Ferdinanda
    ;
    Monti, Antonello
    Modern distribution grids are complex systems that need advanced management for their secure and reliable operation. The Information and Communication Technology domain today offers unprecedented opportunities for the smart design of tools in support of grid operators. This paper presents a new philosophy for the digitalization and automation of distribution grids, based on a modular architecture of microservices implemented via container technology. This architecture enables a service-oriented deployment of the intelligence needed in the Distribution Management Systems, moving beyond the traditional view of monolithic software installations in the control rooms. The proposed architecture unlocks a broad set of possibilities, including cloud-based implementations, extension of legacy systems and fast integration of machine learning-based analytic tools. Moreover, it potentially opens a completely new market of turnkey services for distribution grid management, thus avoiding large upfront investments for grid operators. This paper presents the main concepts and benefits of the proposed philosophy, together with an example of field implementation based on open source components carried out in the context of the European project SOGNO.
  • Publication
    Impact of Cyber-attacks on EV Charging Coordination: The Case of Single Point of Failure
    ( 2022)
    Gumrukcu, Erdem
    ;
    Arsalan, Ali
    ;
    Muriithi, Grace
    ;
    Joglekar, Charukeshi Mayuresh
    ;
    Aboulebdeh, Ahmed
    ;
    Alparslan Zehir, Mustafa
    ;
    Papari, Behnaz
    ;
    Monti, Antonello
    Expanding adoption of electric vehicles (EVs) and broad deployment of charging stations push the limits of distribution grid infrastructure and increase the importance of effective charging coordination. Smart EV chargers with several functionalities and charging coordination solutions that can manage the charging sessions of hundreds of EVs are becoming common, with the increasing risk of triggering significant operational problems in case of cyberattacks. The information exchange between the charging coordinator, distribution network operator, and users is essential in the scheduling of a large number of charging sessions, relying on customer preferences, without violating operational grid constraints. Both the user mobile apps used for charging session reservations and DSO-charging coordinator interfaces are vulnerable to cyberattacks which may cause considerable technical and economic consequences. An important concern is the potential impacts of attacks when a single node or communication link is compromised. This study investigates the impacts of false data injection (FDI) and hijacking attacks on EV charging coordination in case of a single point of failure. Hijacking of one user's mobile app and FDI attack on the DSO-charging coordinator interface are investigated by simulating a 24-hour scenario with 12 chargers, 34 realistic charging sessions, and an EV charging coordination approach based on each session's tolerance to delays. The study highlighted considerable negative impacts that could be encountered in case of a single point of failure in EV charging coordination.
  • Publication
    On Modeling Depths of Power Electronic Circuits for Real-Time Simulation
    ( 2022)
    Carne, De G.
    ;
    Lauss, G.
    ;
    Syed, M.H.
    ;
    Monti, Antonello
    ;
    Benigni, A.
    ;
    Karrari, S.
    ;
    Kotsampopoulos, P.
    ;
    Faruque, M.O.
    Investigations of the dynamic behaviour of power electronic components integrated into electric networks require suitable and established simulation methodologies. Real-time simulation represents a frequently applied methodology for analyzing the steady-state and transient behavior of electric power systems. This work introduces a guideline on how to model power electronics converters in digital real time simulators, taking into account the trade-off between model accuracy and the required computation time. Based on this concept, possible execution approaches with respect to the usage of central processing unit and field-programmable gate array components are highlighted. Simulation test scenario, such as primary frequency regulation and low voltage ride through, have been performed and accuracy indices are discussed for each implemented real-time model and each test scenario, respectively. Finally, a run-time analysis of presented real-time setups is given and real-time simulation results are compared. This manuscript demonstrates important differences in real-time simulation modelling, providing useful guidelines for the decision making of power engineers.
  • Publication
    Comparative Assessment of Shifted Frequency Modeling in Transient Stability Analysis using the Open Source Simulator DPsim
    ( 2022)
    Nakti, Ghassen
    ;
    Dinkelbach, Jan
    ;
    Mirz, Markus
    ;
    Monti, Antonello
    Modern power systems introduce new dynamics, which may require the appropriate selection of the modeling method for each type of dynamic simulation. In this paper, electromagnetic transient (EMT), Root Mean Square (RMS), and Shifted Frequency Analysis (SFA) modeling are compared in the scope of the dynamic simulation of transient stability analysis. The comparison is carried out by analyzing the accuracy of the simulation results as a function of the simulation step size. The evaluation is conducted for classic and low inertia systems for the accuracy of rotor angle transients and the critical clearing time, being the variables of interest in transient stability analysis. The real-time open source simulator DPsim is employed. The main advantage presented by DPsim, is the possibility to run the same simulation scenario with the same solver, but in three different modeling domains. This powerful feature enables a systematic comparison between the modeling methods. With respect to transient stability analysis, the results of the comparative analysis support the usage of SFA, both for classic and low inertia systems. SFA incorporate more dynamics than RMS simulation into the models, while at the same time allowing larger step sizes than EMT simulation.
  • Publication
    SMU Open-Source Platform for Synchronized Measurements
    ( 2022)
    Carducci, C.G.C.
    ;
    Pau, Marco
    ;
    Cazal, C.
    ;
    Ponci, F.
    ;
    Monti, Antonello
    The ramping trend of cheap and performant single board computers (SBC) is growingly offering unprecedented opportunities in various domains, taking advantage of the widespread support and flexibility offered by an operating system (OS) environment. Unfortunately, data acquisition systems implemented in an OS environment are traditionally considered not to be suitable for reliable industrial applications. Such a position is supported by the lack of hardware interrupt handling and deterministic control of timed operations. In this study, the authors fill this gap by proposing an innovative and versatile SBC-based open-source platform for CPU-independent data acquisition. The synchronized measurement unit (SMU) is a high-accuracy device able to perform multichannel simultaneous sampling up to 200 kS/s with sub-microsecond synchronization precision to a GPS time reference. It exhibits very low offset and gain errors, with a minimum bandwidth beyond 20 kHz, SNR levels above 90 dB and THD as low as -110 dB. These features make the SMU particularly attractive for the power system domain, where synchronized measurements are increasingly required for the geographically distributed monitoring of grid operating conditions and power quality phenomena. We present the characterization of the SMU in terms of measurement and time synchronization accuracy, proving that this device, while low-cost, guarantees performance compliant with the requirements for synchrophasor-based applications in power systems.
  • Publication
    SST-Based Grid Reinforcement for Electromobility Integration in Distribution Grids
    ( 2022)
    Joglekar, Charukeshi
    ;
    Mortimer, Benedict
    ;
    Ponci, Ferdinanda
    ;
    Monti, Antonello
    ;
    Doncker, Rik W. de
    Electric Vehicles (EVs) are gaining acceptance due to the advantages they offer in the reduction of nitrogen oxide and carbon dioxide emissions. The need for emission reduction and the potential of EVs for these reductions is reflected in the current sustainable mobility policies of the EU as well as the German government. Increasing the penetration of EVs in the grid requires an expansion of EV charging infrastructure, which in turn requires either grid reinforcement or solutions for more efficient use of existing infrastructure to avoid or postpone grid reinforcement. Distribution transformers face increased loading due to EV charging and need to be protected from overloading during peak load periods to ensure continuity of service. Therefore, transformers are one of the components that are upgraded or replaced as a part of grid reinforcement. In this paper, we propose the connection of a Solid-State Transformers (SST) between two buses operating at the same-voltage level as an alternative to replacement or upgrading of conventional transformer as well as to prevent their overloading. We analyse how the proposed topology can be useful to reduce the impact of EV integration on the overloading of distribution transformers and node voltage violations in the distribution grid.
  • Publication
    Energy informatics. Key elements for tomorrow's energy system
    ( 2022)
    Schmeck, H.
    ;
    Monti, Antonello
    ;
    Hagenmeyer, V.
    The Increasingly Visible effects of climate change necessitate a fundamental transformation of energy systems toward renewable sources. While the Fukushima event led to a particularly strong change in energy policies in Germany, resulting in the so-called Energiewende, or energy transition, the trend toward renewables is visible worldwide. Here, we outline how major challenges of the energy transition have led to a strong need for essential contributions from the computer science community to maintain stability and security of supply, particularly for the electric power grid. As a result, the new discipline of Energy Informatics has emerged which is addressing this highly interdisciplinary and dynamic field of research and development.
  • Publication
    IoT Middleware Platforms for Smart Energy Systems
    ( 2022)
    Alfalouji, Q.
    ;
    Schranz, T.
    ;
    Kümpel, A.
    ;
    Schraven, M.
    ;
    Storek, T.
    ;
    Groß, Stephan
    ;
    Monti, Antonello
    ;
    Müller, D.
    ;
    Schweiger, G.
    Middleware platforms are key technology in any Internet of Things (IoT) system, considering their role in managing the intermediary communications between devices and applications. In the energy sector, it has been shown that IoT devices enable the integration of all network assets to one large distributed system. This comes with significant benefits, such as improving energy efficiency, boosting the generation of renewable energy, reducing maintenance costs and increasing comfort. Various existing IoT middlware solutions encounter several problems that limit their performance, such as vendor locks. Hence, this paper presents a literature review and an expert survey on IoT middleware platforms in energy systems, in order to provide a set of tools and functionalities to be supported by any future efficient, flexible and interoperable IoT middleware considering the market needs. The analysis of the results shows that experts currently use the IoT middleware mainly to deploy services such as visualization, monitoring and benchmarking of energy consumption, and energy optimization is considered as a future application to target. Likewise, non-functional requirements, such as security and privacy, play vital roles in the IoT platforms' performances.