Fraunhofer-Institut für Optronik, Systemtechnik und Bildauswertung IOSB

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  • Publication
    Influence of autoregressive noise on phasor data based disturbance classification
    ( 2021)
    Kummerow, André
    ;
    Dirbas, Mohammad
    ;
    Monsalve, Christian
    ;
    Nicolai, Steffen
    ;
    Bretschneider, Peter
    The automated classification of grid disturbances based on phasor measurement units (PMU) is a key application for a fast and reliable monitoring and control of future power systems. The predominant use of dynamic simulations for the training of the classification models can lead to severe misclassifications during the application phase due to measurement induced error signals. As an advancement to standard white noise approaches, an optimization-based error model is introduced for the synthesis of PMU measurement signals with specific noise characteristics. This approach allows a flexible creation of more sophisticated error signals. Extensive simulation studies are performed for a disturbance classification model based on a recurrent neural network using a large electrical transmission grid.
  • Publication
    Attacking dynamic power system control centers - a cyber-physical threat analysis
    ( 2021)
    Kummerow, André
    ;
    Rüsch, Dennis
    ;
    Nicolai, Steffen
    ;
    Brosinsky, Christoph
    ;
    Westermann, Dirk
    ;
    Naumann, Andre
    In dynamic control centers, conventional SCADA systems are enhanced with novel assistance functionalities to increase existing monitoring and control capabilities. To achieve this, different key technologies like phasor measurement units (PMU) and Digital Twins (DT) are incorporated, which give rise to new cyber-security challenges. To address these issues, a four-stage threat analysis approach is presented to identify and assess system vulnerabilities for novel dynamic control center architectures. For this, a simplified risk assessment method is proposed, which allows a detailed analysis of the different system vulnerabilities considering various active and passive cyber-attack types. Qualitative results of the threat analysis are presented and discussed for different use cases at the control center and substation level.
  • Publication
    The role of digital twins in power system automation and control: Necessity, requirements, and benefits
    ( 2021)
    Brosinsky, Christoph
    ;
    Kummerow, André
    ;
    Richter, Marc
    ;
    Naumann, Andre
    ;
    Nicolai, Steffen
    ;
    Wiest, Pascal
    ;
    Westermann, Dirk
    Recent developments in information technology and operational technology allow novel approaches to operate the electric power system. Thereby, the innovative Digital Twin (DT) is one of the most promising concepts as it addresses increasing requirements in terms of dynamic effects, cyber-physical anomaly detection, modelling accuracy and operator awareness. Based on a brief description of the DT concept and its requirements, we present the potential of DTs for automating power system operation. Special focus is given to modelling, simulation, and communication aspects. DT applications covering system operator coordination, anomaly detection and the coordination of DT-based models between the control centre and intelligent substations are presented. The user perspective is evaluated to provide applicable services and functions of DT-based control system modules. The concept is validated by exemplary numerical case studies.
  • Publication
    Cyber-physical data stream assessment incorporating Digital Twins in future power systems
    ( 2020)
    Kummerow, André
    ;
    Monsalve, Christian
    ;
    Rösch, Dennis
    ;
    Schäfer, Kevin
    ;
    Nicolai, Steffen
    Reliable and secure grid operations become more and more challenging in context of increasing IT/OT convergence and decreasing dynamic margins in today's power systems. To ensure the correct operation of monitoring and control functions in control centres, an intelligent assessment of the different information sources is necessary to provide a robust data source in case of critical physical events as well as cyber-attacks. Within this paper, a holistic data stream assessment methodology is proposed using an expert knowledge based cyber-physical situational awareness for different steady and transient system states. This approach goes beyond existing techniques by combining high-resolution PMU data with SCADA information as well as Digital Twin and AI based anomaly detection functionalities.
  • Publication
    Digital-Twin based Services for advanced Monitoring and Control of future power systems
    ( 2020)
    Kummerow, André
    ;
    Nicolai, Steffen
    ;
    Brosinsky, Christoph
    ;
    Westermann, Dirk
    ;
    Naumann, Andre
    ;
    Richter, Marc
    As real-time applications in information technology (IT) and operational technology (OT) advance, new innovative concepts become possible. IT/OT convergence opens new pathways to design and operate intelligent cyber-physical systems, such as the Digital Twin (DT) concept, which has been discovered as key technology by several industries. This paper describes how centralized and decentralized DTs can help to monitor and control future power systems with special consideration of their interaction in case of corrupted communication from cyber-attacks. While the virtual representation of substations is regarded from the edge computing perspective the control room of the interconnected power system represents the centralized perspective. The concepts allows to have a system wide perspective, while also keeping detailed information at hand. The future system operator in the control room will benefit from services provided by DTs analytical and control features, rising resilience to cyber-physical anomalies and enhance situational awareness.
  • Publication
    Simultaneous online identification and localization of disturbances in power transmission systems
    ( 2019)
    Kummerow, André
    ;
    Monsalve, Christian
    ;
    Nicolai, Steffen
    ;
    Bretschneider, Peter
    Within this survey an approach is presented for the simultaneous online identification and localization of grid disturbances in transmission power systems using different techniques for multivariate time series classification. For the generation of the training data dynamic simulations are performed using DIgSILENT ® PowerFactory combined with a Monte Carlo based initial state selection. Within this survey different classifiers are developed and compared with each other including dynamic time warping, support vector machines, shapelets, recurrent neural networks and random forests. The performance is evaluated in terms of classification accuracy and prediction time.
  • Publication
    Challenges and opportunities for phasor data based event detection in transmission control centers under cyber security constraints
    ( 2019)
    Kummerow, André
    ;
    Rösch, Dennis
    ;
    Monsalve, Christian
    ;
    Nicolai, Steffen
    ;
    Bretschneider, Peter
    ;
    Brosinsky, Christoph
    ;
    Westermann, Dirk
    The scope of this survey is the phasor based event detection under cyber security constraints in modern transmission control centers. A general concept for a physical and cyber event detection is developed as a combination of state-of-the-art disturbance classification and cyber-attack detection methods. This requires the incorporation of heterogeneous data sources and advanced data fusion and analysis techniques. An enhanced and robust recognition of the current grid situation is proposed to distinguish between different scheduled and unscheduled grid events. Furthermore, Digital Twins are considered as new promising technology for control centers and potential benefits for physical and cyber event detection are described.
  • Publication
    PMU-based online and offline applications for modern power system control centers in hybrid AC-HVDC transmission systems
    ( 2019)
    Kummerow, André
    ;
    Brosinsky, Christoph
    ;
    Monsalve, Christian
    ;
    Nicolai, Steffen
    ;
    Bretschneider, Peter
    ;
    Westermann, Dirk
    This investigation presents new control center applications for the management of hybrid AC-DC transmission systems incorporating phasor measurements. This is done by the identification and extraction of critical events from historical and online measurement records as well as dynamic simulation data using artificial intelligence methods. The new control center applications provide a web-based dynamic monitoring interface for the operator assistance.
  • Publication
    Simulation of Coordinated Market Grid Operations considering Uncertainties
    ( 2018)
    Naumann, Steffi
    ;
    Klaiber, Stefan
    ;
    Kummerow, André
    ;
    Bretschneider, Peter
    Within the venture"REGEES" (REGenerative rEnewable Electricity System) a new approach for a Coordinated Market Grid Operation Management (CMGOM) was developed. This approach is investigated in a simulation considering uncertainties. Therefore, the energy time series generator as a method to generate time series for demand and feed-in is described and used to generate simulation input in the form of forecast-scenarios for load and feed-in. Uncertainties in the form of forecast errors and stochastic time series properties are taken into account. The optimization problem, which represents the mathematical description for the acquisition and balancing process of the Balance Responsible Party (BRP), is introduced. Finally, the energy system simulation is described for a test case in order to evaluate the CMGOM approach with consideration of uncertainty. For this purpose, deterministic optimization and two versions of optimization with uncertainties are compared.