Alfred Einfalt

Controlling active low voltage distribution grids with minimum efforts on costs and engineering

Intelligent control approaches for smart low voltage (LV) grids have to meet the future requirements caused by increasing penetration of decentralized generation (DG) from renewable sources and new network participators like electric vehicles. These technical requirements can be solved, but especially in LV networks it is necessary to consider the cost benefit ratio. This paper will therefore focus on active control approaches investigated within the research project “DG DemoNet - Smart LV Grid”. By using an existing Smart Grid metering infrastructure and pursuing the long-term objective of a “plug&automate” solution, the mentioned challenges should be solved with acceptable costs regarding investment, maintenance and operation. In this paper the proposed control concepts for the transformers on-load-tap-changer (OLTC) are in detail discussed along with first experiences from simulations of some of these concepts.

Rapid control prototyping platform for networked smart grid systems

With the progress of the smart grid development and the prototyping of active control solutions supporting grid operation in the presence of a large amount of distributed generators, a design methodology for networked smart grid systems is required. This paper proposes an approach for fast system simulation and emulation-supported prototyping. A distinct tool, the Simulation Message Bus, accompanies the development of distributed controllers for power distribution grids from concept to field application. With this, the idea of an integrated development tool chain as it is known e.g. in the semiconductor or car industry is brought to the energy domain.

Java embedded storage for time series and meta data in Smart Grids

We present a Java-based embedded data store for edge-to-cloud storage optimized for Smart Grid time-series measurements. The key performance indicators expected of applications and operators of a Smart Grid monitoring and control system - frequent readouts, immutability, statistical indicators - are optimally supported. Furthermore, the data store is tailored for operation on platforms with limited storage and processing resources. We show that our implementation is superior to state of the art and off-the-shelf solutions in data retrieval time and needed storage size.

Provisioning, deployment, and operation of smart grid applications on substation level

The transition of classical power distribution grids towards actively operated smart grids locates new functionality into intelligent secondary substations. Increased computational power and newly attained communication infrastructure in thousands of secondary substations allow for the distributed realization of sophisticated functions, which were inconceivable a few years ago. These novel functions (e.g., voltage and reactive power control, distributed generation optimization or decentralized market interaction) can primarily be realized by software components operated on powerful automation devices located on secondary substation level. The effective and safe operation of such software is crucial and has a broad set of requirements. In this paper, we present a flexible and modular software ecosystem for automation devices of substations, which is able to handle these requirements. This ecosystem contains means for high performance data exchange and unification, automatic application provisioning and configuration functions, dependency management, and others. The application of the ecosystem is demonstrated in the context of a field operation example, which has been developed within an Austrian smart grid research project.

Integration von Energiemarkt und Verteilnetzbetrieb durch einen Flexibility Operator

ZusammenfassungDer steigende Anteil volatiler dezentraler Erzeuger im elektrischen Versorgungssystem führt zu einer örtlich erhöhten Netzauslastung und stellt die Balancehaltung zwischen Erzeugung und Verbrauch vor eine Herausforderung. Während im Bereich der steigenden Netzauslastung vor allem Maßnahmen wie Netzausbau oder Smart Grid-Regelungslösungen als Lösungsansatz verfolgt werden, wird im Bereich der Systembalance vor allem auf Marktmechanismen gesetzt. Es ist zu erwarten, dass zukünftig kleine Erzeugungsanlagen zu Spitzenzeiten aufgrund von Netzengpässen nur einen Teil ihrer zur Verfügung stehenden Leistung einspeisen können. Gleichzeitig ist zu erwarten, dass zukünftig kleine Anlagen in (ggf. wechselnden) Vertragsverhältnissen mit virtuellen Kraftwerken stehen und bestimmte vorab geregelte Leistungen erbringen. Vor dem Hintergrund dieser Entwicklungen sind eindeutige Regeln im Umgang mit Netzkonflikten zu definieren. Eine mögliche auch in dieser Arbeit verfolgte Strategie ist die Suche nach geeigneten Marktmechanismen, die einen volkswirtschaftlich sinnvollen Netzausbau ermöglichen. Solche Mechanismen müssen auch geeignete lokale Flexibilitätsmärkte enthalten, die es erlauben, Netzengpässe auszugleichen. In dieser Arbeit werden Strategien und technische Schnittstellen zur Koordination von Markt und Netz in Form eines „Flexibility Operators“ vorgeschlagen und dessen Einbettung in ein Smart Grid-Gesamtkonzept diskutiert.AbstractThe growing share of volatile distributed generation in the electric power grids results in increased local network utilisation and challenges the conventional strategies for maintaining the system balance. While grid extensions and smart grid solutions are considered for network utilisation issues, new market mechanisms are in focus for the balancing challenge. It can be expected that distributed generators on one hand will be able to supply only part of their available power to the grid in peak times, and on the other hand will have (potentially changing) contracts with different trans-regional virtual power plants. Against this background it will be necessary to define rules dealing with expected network access conflicts. One strategy also followed in this work is to find market mechanisms that support economically efficient network extension. Such mechanisms will have to include local flexibility markets that allow for compensating network bottlenecks. This work proposes strategies and technical interfaces for coordinating market and grid operation by means of a “Flexibility Operator”. Its integration into a holistic smart grid concept is discussed.

Short-term aggregated load and distributed generation forecast using fuzzy grouping approach

The increasing shares of renewable energy sources at low voltage distribution nodes are the cause of increased operational uncertainty. This uncertainty must also be taken into account during operational planning for the short term period, i.e. up to five days ahead. Therefore the system operators must take into account how low-voltage load as well as generation change at each node in the near future. This requires appropriate short-term forecast load and distributed generation (DG) methods. In the past, standard profiles for nodes were used to approximately forecast the expected load in the absence of smart metering and historical time-series storage. With increased number of smart meters in the grid, it is possible to use more complex methods to more accurately forecast system load and generation and therefore ensure secure system operation. In this paper, we present the forecasting approach used for load and distributed generation nodes equipped with smart meters. The presented approach was designed at SIEMENS as one part of the Austrian nationally founded research project ProAktivNetz. The forecasts represent aggregated load and distributed generation nodal injection values. The approach was tested for a small node with 100 households and a 34 kWp photovoltaic power plant. The results show that the grouped forecast results using the fuzzy weighting procedure give better forecasting results than individual methods and significantly better results than using standard profiles for the nodes.

Active distribution management vs. selective automation for urban distribution grids

This contribution will focus on a developed tool within the national founded research project “REstrukt-DEA”. The aim of this tool is to provide the possibility of comparison and evaluation of complete different selective restructuring and operation measures of distribution grids with selective smart grid technologies, like active distribution management or selective automation. To show the future use of the tool a brief summary of relevant Austrian research projects addressing this topic is given, the structure of the tool is presented and a first example of the representation and interpretation of simulation results using the tool is shown.

Grid watch dog: a stream reasoning approach for lightweight SCADA functionality in low-voltage grids

The advent of distributed energy resources in conjunction with recent developments in the context of smart embedded devices has fostered the increased integration of intelligent generators and prosumers into the energy system. As a consequence, previously passively operated grids have become highly dynamic environments, which require active monitoring and control. To allow for such monitoring and control, grid operators require lightweight SCADA-like functionality that can be flexibly adapted to dynamic grid contexts and is suitable for resource-constrained embedded systems. Grid Watch Dog enables system operators to create monitoring and control rules for low-voltage field devices on the fly, and to immediately deploy them in the field. The system combines a stream reasoner on field devices with an intuitive user interface for creating and managing rules. Grid Watch Dog has been implemented as a proof of concept in a smart grid testbed and we demonstrate its application in the context of monitoring a battery energy storage system.

Reactive Operation: A Framework for Event Driven Low Voltage Grid Operation

This proposal presents a prototypical realization of the “Reactive Operations” concept. The core feature of the “reactive operations” is to present an operator only with information in case this information is required by the operator to identify unsuitable system behavior (e.g. if faults occur) and to bundle the presented information event specific. This contrasts conventional supervisory control and data acquisition (SCADA) systems which constantly present an operator with specific system information.

Industrial IoT für Smart Grid-Anwendungen im Feld

ZusammenfassungDie Energiewende bewirkt eine Transformation des Energiesystems, die zu großen Herausforderungen für den Verteilernetzbetrieb führt. Dies ist der Tatsache geschuldet, dass bis dato passive Verteilernetz-Abschnitte, welche historisch reine Verbraucher waren, nunmehr durch dort verortete dezentrale Erzeugung und proaktive Netzteilnehmer – wie Photovoltaikanlage, Speicher und E-Mobility – aktiv Einfluss auf den Netzbetrieb nehmen. Durch die Integration und den Einsatz intelligenter Automatisierung sollen diese Netzabschnitte in Zukunft aktiv gesteuert werden. Das daraus resultierende Gesamtsystem stellt ein cyber-physikalisches System dar, dass durch einen hohen Komplexitätsgrad gekennzeichnet ist und die elektrische und algorithmische Welt mittels geeigneter IKT-Infrastruktur koppelt. Es ist davon auszugehen, dass die Steuerung und Automatisierung in solchen Systemen immer individueller wird. Dafür bedarf es flexibler und (hinsichtlich Installation und Wartung) einfach zu bedienender Automatisierungssysteme, die es den Betreibern von Verteilernetzen erlauben, individualisierte Lösungen nahtlos in ihren Netzen zu integrieren. Dieser Beitrag beschreibt einen Systemansatz, der aufbauend auf einer Industrial Internet-of-Things(IoT)-Plattform die Interaktion der notwendigen physikalischen Modelle und Anwendungen realisiert und somit zur Lösung dieser Herausforderungen eingesetzt werden kann.AbstractCurrently an increased integration of distributed energy resources and prosumers into the distribution system can be observed. These new resources range from renewable energy resources such as PV-systems, to storage systems, and e-mobility charging stations. This trend is coined under the term “Energiewende” and presents a challenge for the system operators, as the grid-level (where the integration of these entities happens) was initially designed for distribution purposes only and was thus operated passively. In order to mitigate and solve resulting problems, intelligent automation systems can be used to actively operate these grids. The resulting system constitutes a cyber physical system, which is characterized by a high degree of complexity and connects the electrical and the algorithmic world, using a suitable ICT infrastructure. As the control and automatization of such systems becomes more and more individual, flexible and simple to use (regarding installation and maintenance) automation systems are required, which allow the operator the seamless integration of individualized solutions into their grids. This article describes a system approach that is based on industrial Internet-of-Things technology and allows realizing the required interaction between the physical models and applications; thus presenting a solution to solve these challenges.