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Interactions between different energy carriers (electricity, heat and gas) are considered beneficial for using renewable energy and reducing carbon emissions in the energy system. Nevertheless, the establishment of such hybrid grids or systems, also called multi-, integrated or smart energy systems, remains relatively unexplored. The concept is characterised by great complexity, questioning the common isolated view of energy grids. This paper analyses the changing requirements from historically grown, isolated energy grids towards renewable hybrid energy systems and the associated potential and challenges. A hybrid grid offers alternative use options, which make energy production and consumption more flexible. No peer-reviewed research provides quantitative analysis on the expected utilisation of the electricity, gas and thermal grid in a hybrid grids scenario. However, the traditional grids will compete among each other and increasingly with distributed power generation and consumption by prosumers. In addition, a reversal and reduction of the gas grid and possible new structures of a hydrogen network have to be considered. To achieve the desired savings in energy demand and carbon emissions while maintaining the security of supply and economic feasibility in hybrid energy systems, appropriate technologies, infrastructure financing, integrated system planning based on the relevant data and supportive market frameworks are required.
J. Ramsebner; R. Haas; H. Auer; A. Ajanovic; W. Gawlik; C. Maier; S. Nemec-Begluk; T. Nacht; M. Puchegger. From single to multi-energy and hybrid grids: Historic growth and future vision. Renewable and Sustainable Energy Reviews 2021, 151, 111520 .
AMA StyleJ. Ramsebner, R. Haas, H. Auer, A. Ajanovic, W. Gawlik, C. Maier, S. Nemec-Begluk, T. Nacht, M. Puchegger. From single to multi-energy and hybrid grids: Historic growth and future vision. Renewable and Sustainable Energy Reviews. 2021; 151 ():111520.
Chicago/Turabian StyleJ. Ramsebner; R. Haas; H. Auer; A. Ajanovic; W. Gawlik; C. Maier; S. Nemec-Begluk; T. Nacht; M. Puchegger. 2021. "From single to multi-energy and hybrid grids: Historic growth and future vision." Renewable and Sustainable Energy Reviews 151, no. : 111520.
Battery Energy Storage Systems (BESS) based on Li-Ion technology are considered to be one of the providers of services in the future power system. Although prices for Li-Ion batteries are falling continuously, it is still difficult to achieve profitability from a single service today. Multi-use operation of BESS in order to reach a so-called “value-stacking” of services therefore is a hotly debated topic in literature, since such an operation holds the potential to increase profitability dramatically. The multi-use operation of a BESS can be divided into two parts: the operational planning phase and the real-time operation. While the operational planning phase has been examined in many studies, there seems to be a lack of discussion for the real-time operation. This paper therefore tries to address the topic of the real-time operation in more detail. For this reason, this paper discusses concepts for implementing a real-time multi-use operation and introduces the novel concept of dynamic prioritization, which allows resolving conflicts of services. Besides the ability to cope with abnormal grid conditions, this concept also holds potential for a better utilization of resources during normal grid conditions. A mathematical framework is used to describe several services and their interaction, taking into account the concept of dynamic prioritization. Several applications are presented in order to demonstrate the behavior of the concept during normal and abnormal grid conditions. These applications are simulated in Matlab/Simulink for specific events and in the form of long-time simulations.
Jürgen Marchgraber; Wolfgang Gawlik. Dynamic Prioritization of Functions During Real-Time Multi-Use Operation of Battery Energy Storage Systems. Energies 2021, 14, 655 .
AMA StyleJürgen Marchgraber, Wolfgang Gawlik. Dynamic Prioritization of Functions During Real-Time Multi-Use Operation of Battery Energy Storage Systems. Energies. 2021; 14 (3):655.
Chicago/Turabian StyleJürgen Marchgraber; Wolfgang Gawlik. 2021. "Dynamic Prioritization of Functions During Real-Time Multi-Use Operation of Battery Energy Storage Systems." Energies 14, no. 3: 655.
Increasing penetration of power-electronics-converter-interfaced generation and loads raises several challenges for the operation, control and protection of power systems. This paper investigates the impact of high penetration of Power Electronic Interfaced Power Sources (PEIPS) on frequency control, and aspects of provision of synthetic inertia (SI) by PEIPS. Contrary to directly connected conventional synchronous machines, which provide inertia to the system inherently, thus effectively counteracting large gradients in the system frequency (rate of change of frequency, RoCoF), PEIPS need to be operated under specially designed control schemes in order to provide synthetic inertia by varying their power output proportionally to the RoCoF. Implementing such control schemes for current-controlled PEIPS requires both accurate and fast frequency measurement and can rather approximately reproduce physical inertia added to the system by directly connected synchronous machines. While the transient behavior of conventional synchronous machines is defined by their well-known electromechanical properties, the dynamic behavior of PEIPS is mostly dictated and limited by their control strategy and pertinent measurements. Under this setup, it is worth contemplating strategies that go beyond mimicking the dynamic capabilities of synchronous machines. A synchronous machine provides inertia to the system inherently due to its rotating mass. However, current-controlled PEIPS implement synthetic inertia by measuring frequency, calculating the frequency gradient and providing power accordingly. The delays due to frequency measurement, RoCoF computation and current control reflect an inherent difference and disadvantage of synthetic inertia compared to real inertia and must be properly studied to avoid deterioration of system stability under a large penetration of PEIPS. While the behavior of synchronous machines is determined by their physical properties, the behavior of PEIPS may be altered by modifying their control regime in order to improve their transient behavior under higher RoCoF values. Furthermore, it is possible to implement non-linear strategies that do not depend only on the frequency gradient but also on the frequency deviation. One option to achieve this is to implement different activation areas for different signs of both frequency deviation and RoCoF. Such a zone-selective implementation of synthetic inertia, realized by an activation function, could avoid that synthetic inertia counteracts the effect of other control reserves during recovery from frequency deviations, i.e., after the frequency nadir has occurred. This paper investigates such options and their impact on the frequency stability of the power system when synthetic inertia is provided by PEIPS.
W. Gawlik; C. Alacs; J. Marchgraber; Y. Guo; A. Anta; J. Kathan; B. Weiss; K. Oberhauser; M. Lenz; M. Froschauer; A. Stimmer; M. Leonhardt. Improving synthetic inertia provision by Power Electronic Interfaced Power Sources to support future system stability. e & i Elektrotechnik und Informationstechnik 2020, 137, 460 -469.
AMA StyleW. Gawlik, C. Alacs, J. Marchgraber, Y. Guo, A. Anta, J. Kathan, B. Weiss, K. Oberhauser, M. Lenz, M. Froschauer, A. Stimmer, M. Leonhardt. Improving synthetic inertia provision by Power Electronic Interfaced Power Sources to support future system stability. e & i Elektrotechnik und Informationstechnik. 2020; 137 (8):460-469.
Chicago/Turabian StyleW. Gawlik; C. Alacs; J. Marchgraber; Y. Guo; A. Anta; J. Kathan; B. Weiss; K. Oberhauser; M. Lenz; M. Froschauer; A. Stimmer; M. Leonhardt. 2020. "Improving synthetic inertia provision by Power Electronic Interfaced Power Sources to support future system stability." e & i Elektrotechnik und Informationstechnik 137, no. 8: 460-469.
Microgrids are small scale electrical power systems that comprise distributed energy resources (DER), loads, and storage devices. The integration of DER into the electrical power system basically allows the clustering of small parts of the main grid into Microgrids. Due to the increasing amount of renewable energy, which is integrated into the main grid, high power fluctuations are expected to become common in the next years. This carries the risk of blackouts to be also more likely in the future. Microgrids hold the potential of increasing reliability of supply, since they are capable of providing a backup supply during a blackout of the main grid. This paper investigates the black-starting and islanding capabilities of a battery energy storage system (BESS) in order to provide a possible backup supply for a small part of the main grid. Based on field tests in a real Microgrid, the backup supply of a residential medium voltage grid is tested. Whereas local wind turbines within this grid section are integrated into this Microgrid during the field test, the supply of households is reproduced by artificial loads consisting of impedance- and motor loads, since a supply of real households carries a high risk of safety issues and open questions regarding legal responsibility. To operate other DER during the island operation of such a Microgrid, control mechanisms have to ensure the power capabilities and energy reserves of the BESS to be respected. Since the operation during a backup supply of such a Microgrid requires a simple implementation, this paper presents a simple master–slave control approach, which influences the power output of other DER based on frequency characteristics without the need for further communication. Besides the operation of other DER, the capability to handle load changes during island operation while ensuring acceptable power quality is crucial for such a Microgrid. With the help of artificial loads, significant load changes of the residential grid section are reproduced and their influence on power quality is investigated during the field tests. Besides these load changes, the implementation and behavior of the master–slave control approach presented in this paper is tested. To prepare these field tests, simulations in Matlab/Simulink are performed to select appropriate sizes for the artificial loads and to estimate the expected behavior during the field tests. The field tests prove that a backup supply of a grid section during a blackout of the main grid by a BESS is possible. By creating the possibility of operating other DER during this backup supply, based on the master–slave control approach presented in this paper, the maximum duration for this backup supply can be increased.
Jürgen Marchgraber; Wolfgang Gawlik. Investigation of Black-Starting and Islanding Capabilities of a Battery Energy Storage System Supplying a Microgrid Consisting of Wind Turbines, Impedance- and Motor-Loads. Energies 2020, 13, 5170 .
AMA StyleJürgen Marchgraber, Wolfgang Gawlik. Investigation of Black-Starting and Islanding Capabilities of a Battery Energy Storage System Supplying a Microgrid Consisting of Wind Turbines, Impedance- and Motor-Loads. Energies. 2020; 13 (19):5170.
Chicago/Turabian StyleJürgen Marchgraber; Wolfgang Gawlik. 2020. "Investigation of Black-Starting and Islanding Capabilities of a Battery Energy Storage System Supplying a Microgrid Consisting of Wind Turbines, Impedance- and Motor-Loads." Energies 13, no. 19: 5170.
The increasing amount of renewable energy sources in the electrical energy system leads to an increasing number of converter-based generators connected to the electrical power grid. Other than conventional power plants that are often connected to the grid via synchronous generators, converter-based generators do not provide mechanical inertia intrinsically. Therefore, ensuring frequency stability in the electrical power grid might become even more difficult in the future. With the concept of synthetic inertia, the converter-based generators partially imitate the behavior of conventional generators. By implementing such a concept in converters, they are capable of contributing to frequency stability as well. This paper compares two strategies to realize synthetic inertia by modeling converter-based generators in MATLABmathsizesmall/SIMULINKmathsizesmall and simulating their behavior in a small Microgrid. The results prove that any kind of realization of synthetic inertia helps to improve frequency stability. Each of the two investigated strategies may have their scope of application in a future electrical energy system.
Jürgen Marchgraber; Christian Alács; Yi Guo; Wolfgang Gawlik; Adolfo Anta; Alexander Stimmer; Martin Lenz; Manuel Froschauer; Michaela Leonhardt. Comparison of Control Strategies to Realize Synthetic Inertia in Converters. Energies 2020, 13, 3491 .
AMA StyleJürgen Marchgraber, Christian Alács, Yi Guo, Wolfgang Gawlik, Adolfo Anta, Alexander Stimmer, Martin Lenz, Manuel Froschauer, Michaela Leonhardt. Comparison of Control Strategies to Realize Synthetic Inertia in Converters. Energies. 2020; 13 (13):3491.
Chicago/Turabian StyleJürgen Marchgraber; Christian Alács; Yi Guo; Wolfgang Gawlik; Adolfo Anta; Alexander Stimmer; Martin Lenz; Manuel Froschauer; Michaela Leonhardt. 2020. "Comparison of Control Strategies to Realize Synthetic Inertia in Converters." Energies 13, no. 13: 3491.
Integrating distributed generation into power grids creates various technical challenges for network operation. Volatility of renewable energy resources may increase the probability of blackouts. In order to restore networks fast, securely and reliably after blackouts, within the research project RestoreGrid4RES’s network restoration strategies, the related issues caused by distributed generation are investigated and novel methods to face those challenges are developed. This paper focuses on (i) algorithms to identify possible restoration paths, (ii) key performance indicators for the assessment of grid restoration options and (iii) an evaluation of the results for network restoration strategies.
Elmira Torabi Makhsos; Yi Guo; Wolfgang Gawlik; Benjamin Cox; Philipp Hinkel; Marian Zugck; Wolfram Wellßow; Robert Schmaranz; Ewald Traxler; Leopold Fiedler. Investigation of Fast, Secure and Reliable Network Restoration after Blackouts. Energies 2020, 13, 3019 .
AMA StyleElmira Torabi Makhsos, Yi Guo, Wolfgang Gawlik, Benjamin Cox, Philipp Hinkel, Marian Zugck, Wolfram Wellßow, Robert Schmaranz, Ewald Traxler, Leopold Fiedler. Investigation of Fast, Secure and Reliable Network Restoration after Blackouts. Energies. 2020; 13 (11):3019.
Chicago/Turabian StyleElmira Torabi Makhsos; Yi Guo; Wolfgang Gawlik; Benjamin Cox; Philipp Hinkel; Marian Zugck; Wolfram Wellßow; Robert Schmaranz; Ewald Traxler; Leopold Fiedler. 2020. "Investigation of Fast, Secure and Reliable Network Restoration after Blackouts." Energies 13, no. 11: 3019.
Correspondence to Wolfgang Gawlik. Der Verlag bleibt in Hinblick auf geografische Zuordnungen und Gebietsbezeichnungen in veröffentlichten Karten und Institutsadressen neutral. Reprints and Permissions Gawlik, W. Vorwort. Elektrotech. Inftech. (2020). https://doi.org/10.1007/s00502-020-00807-8 Download citation Published: 04 June 2020 DOI: https://doi.org/10.1007/s00502-020-00807-8
Wolfgang Gawlik. Vorwort. e & i Elektrotechnik und Informationstechnik 2020, 137, 135 -135.
AMA StyleWolfgang Gawlik. Vorwort. e & i Elektrotechnik und Informationstechnik. 2020; 137 (4-5):135-135.
Chicago/Turabian StyleWolfgang Gawlik. 2020. "Vorwort." e & i Elektrotechnik und Informationstechnik 137, no. 4-5: 135-135.
To ensure system stability, national grid codes often require converter-based generators to provide fault-ride-through (FRT) capabilities and dynamic voltage support, according to which they should stay connected and support the voltage during fault situations. The requirements for dynamic voltage support include the injection of reactive current in the positive- as well as negative-sequence system, directly proportional to the change of the corresponding voltage between fault and pre-fault. Since this requirement may lead to a reference current surpassing the maximum current capability, the converter control has to contain a proper current limitation. This paper presents an algorithm for such a current limitation and a simulation model of a converter and its control, which applies this algorithm. Based on voltage measurements, which were measured during forced short-circuits in the real grid, the simulation model is used to simulate the behavior of a converter in reaction to these voltage measurements. The results show that the converter control using this algorithm for current limitation guarantees a current output below the maximum current capability while respecting the requirements for dynamic voltage support of the relevant grid codes.
Jürgen Marchgraber; Wolfgang Gawlik. Dynamic Voltage Support of Converters during Grid Faults in Accordance with National Grid Code Requirements. Energies 2020, 13, 2484 .
AMA StyleJürgen Marchgraber, Wolfgang Gawlik. Dynamic Voltage Support of Converters during Grid Faults in Accordance with National Grid Code Requirements. Energies. 2020; 13 (10):2484.
Chicago/Turabian StyleJürgen Marchgraber; Wolfgang Gawlik. 2020. "Dynamic Voltage Support of Converters during Grid Faults in Accordance with National Grid Code Requirements." Energies 13, no. 10: 2484.
Umrichterbasierte Einspeisungen konnten bisher in Kurzschlussberechnungen aufgrund ihrer geringen Anzahl und ihrem verhältnismäßig geringen Kurzschlussbeitrag vernachlässigt werden. In der aktualisierten Norm zur Kurzschlussrechnung IEC 60909-0:2016 (2016) wird eine Berücksichtigung dieser Anlagen ab einem Beitrag zum Kurzschlussstrom von 5% gefordert. Der Kurzschlussbeitrag wird darin als der einer Stromquelle im Mitsystem angenähert. Das Verhalten im Gegensystem wird nicht näher definiert, und es wird angemerkt, dass dieses als projektspezifisch festzusetzen ist. Im Hinblick auf die zunehmende Verbreitung umrichterbasierter Einspeiser können gegebenenfalls Untersuchungen nötig sein, welche eine detaillierte Abbildung des Kurzschlussverhaltens solcher Anlagen erfordern. In Österreich beschreibt die TOR D4 (2016) die Anforderungen von umrichterbasierten Einspeisern im Kurzschlussfall. Die beschriebenen Anforderungen sind aber stellenweise unzureichend definiert. In Deutschland werden in der VDE-AR-N-4110:2017-02 (2017) die Anforderungen genauer spezifiziert. Es kann angenommen werden, dass Aktualisierungen der TOR D4 (2016) diese Spezifikationen aufgreifen werden. Um die Möglichkeit zu eröffnen, eine detaillierte Untersuchung von Fehlerfällen mit Kurzschlusstrom-Beiträgen aus umrichterbasierten Einspeisern zu ermöglichen, wird im vorliegenden Beitrag ein Modell vorgestellt, welches die Anforderungen gemäß VDE-AR-N-4110:2017-02 (2017) hinsichtlich des Kurzschussverhaltens erfüllt. Anhand eines realen Netzabschnitts wird der Einfluss eines umrichterbasierten Einspeisers auf die Netzgrößen im Kurzschlussfall dargestellt. Im untersuchten Netzabschnitt wurden Netzkurzschlussversuche durchgeführt (vgl. Wurm in E&I, Elektrotech. Inf.tech. 2019), sodass ein Vergleich mit den simulierten Ergebnissen des Modells möglich ist. Inverter-based generation has so far been neglected in short-circuit calculations due to their small number and their relatively low short-circuit contribution. The latest revision of the standard for short-circuit calculations IEC 60909-0:2016 (2016) requires a consideration of inverter-based infeed if their contribution to the short-circuit current is at least 5%. In the case of a contribution exceeding 5% the short-circuit contribution of inverter-based infeed is approximated by a current source in the positive-sequence system. The behavior in the negative-sequence system is not further defined and it is noted that this has to be determined as project-specific. Because of the increasing popularity of inverter-based infeed, studies may be required that call for a detailed description of the short-circuit behavior of such equipment. In Austria, TOR D4 (2016) describes the requirements of inverter-based infeed in case of a short circuit. However, these requirements have a lack of detail, especially regarding the behavior in the negative-sequence system. In Germany, the requirements are specified more precisely in VDE-AR-N-4110: 2017-02 (2017). It can be assumed that future revisions of TOR D4 (2016) will take up these specifications. In order to open up the possibility of a detailed investigation of faults with contributing inverter-based infeed, this article presents a model which meets the requirements according to VDE-AR-N-4110: 2017-02 (2017). Based on a real grid section, the influence of inverter-based infeed during short-circuits is shown. In the studied grid section, short-circuit tests were performed (see Wurm in E&I, Elektrotech. Inf.tech. 2019), so that a comparison of the simulated results of the model with the measured values is possible.
Jürgen Marchgraber; Wolfgang Gawlik; Manfred Wurm. Modellierung der dynamischen Netzstützung von über Umrichter angebundenen Erzeugungsanlagen und Speichern. e & i Elektrotechnik und Informationstechnik 2019, 136, 31 -38.
AMA StyleJürgen Marchgraber, Wolfgang Gawlik, Manfred Wurm. Modellierung der dynamischen Netzstützung von über Umrichter angebundenen Erzeugungsanlagen und Speichern. e & i Elektrotechnik und Informationstechnik. 2019; 136 (1):31-38.
Chicago/Turabian StyleJürgen Marchgraber; Wolfgang Gawlik; Manfred Wurm. 2019. "Modellierung der dynamischen Netzstützung von über Umrichter angebundenen Erzeugungsanlagen und Speichern." e & i Elektrotechnik und Informationstechnik 136, no. 1: 31-38.
Über leistungselektronische Konverter an das Verbundsystem angebundene Einspeiser stellen, anders als direkt angebundene Synchrongeneratoren, keine rotierende Masse für das Verbundsystem zur Verfügung. Das bedeutet, dass sich die Dynamik im schwingungsfähigen Verbundsystem grundsätzlich und in den kommenden Jahren in immer stärkerem Ausmaß verändern wird. Je kleiner die Schwungmasse ist, desto schneller ändert sich die Frequenz bei einem Ungleichgewicht zwischen Erzeugung und Verbrauch. Zur Aktivierung von Regelreserven bleibt damit weniger Zeit, bis kritische Frequenzwerte erreicht werden, bei denen die Integrität des Verbundsystems nicht mehr gewährleistet werden kann. Diese Arbeit beschäftigt sich mit der Betrachtung von schnellerer Regelleistung im Zusammenspiel mit der Schwungmasse im System. Zur Gewährleistung einer ausreichenden Frequenzstabilität im Verbundsystem ergeben sich drei Lösungsansätze, die auf der schnelleren Bereitstellung von Regelleistung basieren: Sicherstellung einer ausreichend großen reellen Schwungmasse, Einspeisung von zusätzlicher Erzeugungsleistung basierend auf dem Frequenzgradienten \(df/dt\) und schnellere Einspeisung von zusätzlicher Erzeugungsleistung basierend auf der Frequenzabweichung \(\Delta f\). Der Bedarf hängt neben den vorauszusetzenden Systemeigenschaften von der Zusammensetzung und Parametrierung dieser Regelleistungen ab. The increasing penetration of power electronic interfaced power sources, in contrast to traditional synchronous generators, leads to a decrease of inertia in the power system. That will result in significant changes in the dynamics of the European power systems in terms of frequency deviations and oscillations. The lower the inertia becomes, the higher the rate of change of frequency after imbalances of generation and load in the system. Thus, there is less time to activate control reserves to avoid system frequencies that may endanger the integrity of the system. This paper is investigating the requirements and interaction of control reserves faster than the current frequency containment reserves. To maintain a sufficient frequency stability of the system, three options are presented: Ensuring sufficient real inertia in the system, providing synthetic inertia based on the rate of change of frequency, and providing control reserves based on the frequency deviation, but activated faster than current primary control reserves. The requirements depend on the system properties and combination and parameterization of these reserves.
Wolfgang Gawlik; Alireza Kerdegarbakhsh; Markus Pešek; Christian Alács. Entwicklung des Bedarfs an schneller Regelleistung im europäischen Verbundsystem. e & i Elektrotechnik und Informationstechnik 2018, 135, 507 -513.
AMA StyleWolfgang Gawlik, Alireza Kerdegarbakhsh, Markus Pešek, Christian Alács. Entwicklung des Bedarfs an schneller Regelleistung im europäischen Verbundsystem. e & i Elektrotechnik und Informationstechnik. 2018; 135 (8):507-513.
Chicago/Turabian StyleWolfgang Gawlik; Alireza Kerdegarbakhsh; Markus Pešek; Christian Alács. 2018. "Entwicklung des Bedarfs an schneller Regelleistung im europäischen Verbundsystem." e & i Elektrotechnik und Informationstechnik 135, no. 8: 507-513.
This paper presents a methodology that aims at identifying virtual inertia (VI) gain limitations from virtual synchronous generators (VSGs) while maintaining the frequency stability considering the delay associated with the frequency measurement process. The phase-locked loop (PLL) is typically used for frequency estimation that is used to calculate the rate of change of frequency (RoCoF) and it drives the VI loop. The PLL is generally accompanied by a low-pass filter that aims to suppress the impact of harmonics. This filter introduces a delay that when used with the VI control loop causes stability issues for high values of VI gain. A comparison of various PLL approaches suggests that certain variants tend to permit higher value of cut-off frequencies which can be utilized to increase the VI gain limit from VSG. This study presents a method by which the upper limit on VI gain can be quantified and related to the cut-off frequency of the PLL low pass filter that is indirectly representing the delay. It is performed using small signal frequency stability analysis on the frequency domain model of the grid with virtual inertia emulating VSG. The effective maximum VI gain from VSG is explored while satisfying the frequency measurement accuracy specification considering harmonics. The results show that the requirements of reaching a stable operation with sufficient stability margins can still be met with a faster PLL-based system and the potential increases in VI support from VSG can be quantified using the proposed method. The study has been first performed on a single machine single inverter bus (SMSIB) system and is generalized to the multi-machine and multi-inverter system.
Sohail Khan; Benoit Bletterie; Adolfo Anta; Wolfgang Gawlik. On Small Signal Frequency Stability under Virtual Inertia and the Role of PLLs. Energies 2018, 11, 2372 .
AMA StyleSohail Khan, Benoit Bletterie, Adolfo Anta, Wolfgang Gawlik. On Small Signal Frequency Stability under Virtual Inertia and the Role of PLLs. Energies. 2018; 11 (9):2372.
Chicago/Turabian StyleSohail Khan; Benoit Bletterie; Adolfo Anta; Wolfgang Gawlik. 2018. "On Small Signal Frequency Stability under Virtual Inertia and the Role of PLLs." Energies 11, no. 9: 2372.
The increasing power in-feed of Non-Synchronous Renewable Energy Sources (NS-RES) in the grid has raised concerns about the frequency stability. The volatile RES power output and absence of inertia in many types of NS-RES affect the balance between power consumption and production. Therefore, the dynamics of the power grid frequency become more complex. Extreme grid frequency deviations and fast variations can lead to partitioning and load shedding in the case of under-frequency. In the case of over-frequency, it can lead to overloading, voltage collapse and blackouts. The Rate of Change of Frequency (RoCoF) reflects an aspect of the stability status of the grid and therefore its analysis with regard to Non-Synchronous Instant Penetration (NSIP) is of great importance. In this work, two months of high-resolution frequency synchrophasor measurements during 18 January 2018–18 March 2018 recorded in Austria were analyzed to investigate the impact of NS-RES on the frequency. The correlation of RoCoF with the NSIP in Austria and Germany and with the frequency deviation were examined. It was observed that with a maximum NSIP share up to 74% of the total power generation in these two countries, there was no critical increase of RoCoF or abnormal frequency deviation in the power grid.
Evangelia Xypolytou; Wolfgang Gawlik; Tanja Zseby; Joachim Fabini. Impact of Asynchronous Renewable Generation Infeed on Grid Frequency: Analysis Based on Synchrophasor Measurements. Sustainability 2018, 10, 1605 .
AMA StyleEvangelia Xypolytou, Wolfgang Gawlik, Tanja Zseby, Joachim Fabini. Impact of Asynchronous Renewable Generation Infeed on Grid Frequency: Analysis Based on Synchrophasor Measurements. Sustainability. 2018; 10 (5):1605.
Chicago/Turabian StyleEvangelia Xypolytou; Wolfgang Gawlik; Tanja Zseby; Joachim Fabini. 2018. "Impact of Asynchronous Renewable Generation Infeed on Grid Frequency: Analysis Based on Synchrophasor Measurements." Sustainability 10, no. 5: 1605.
Wolfgang Gawlik. Elektrische Energieversorgung – Wunsch und Wirklichkeit. e & i Elektrotechnik und Informationstechnik 2017, 134, 469 -469.
AMA StyleWolfgang Gawlik. Elektrische Energieversorgung – Wunsch und Wirklichkeit. e & i Elektrotechnik und Informationstechnik. 2017; 134 (8):469-469.
Chicago/Turabian StyleWolfgang Gawlik. 2017. "Elektrische Energieversorgung – Wunsch und Wirklichkeit." e & i Elektrotechnik und Informationstechnik 134, no. 8: 469-469.
The number of fluctuating distributed energy resources (DER) in electricity grids is continuously rising. Due to the lack of operational information on low-voltage (LV) networks, conservative assumptions are necessary to assess the connection of generators to the grid. This paper introduces the hosting capability (HC) as a measure to assess the amount of DER that can be integrated in LV-feeders. The HC of a feeder is the minimum amount of DER that can be hosted in a feeder without reinforcement needs for a given DER-scenario and for a given admissible voltage rise. The hosting capability assessment was performed on the entire LV-grid data of two Austrian Distribution System Operators (DSOs) with more than 36,000 LV-feeders. In total, 40 HC-scenarios were calculated with varying admissible voltage rise levels, DER-scenarios and reactive power control strategies. It turned out that only few feeder parameters such as the resistance at the end node and the lowest ampacity value of feeders show a high correlation with the calculated HC. Further, the impact of the DER-scenario on the share of voltage and loading constrained feeders is rather limited. The gathered results are suitable to validate equivalent LV-feeders models to perform integrated power flow studies on the transmission and distribution grids. Besides the results obtained for the network data of the two DSOs, a performant, modular and parallelizable tool has been developed to automatically analyze large LV network sets.
Serdar Kadam; Benoît Bletterie; Wolfgang Gawlik. A Large Scale Grid Data Analysis Platform for DSOs. Energies 2017, 10, 1099 .
AMA StyleSerdar Kadam, Benoît Bletterie, Wolfgang Gawlik. A Large Scale Grid Data Analysis Platform for DSOs. Energies. 2017; 10 (8):1099.
Chicago/Turabian StyleSerdar Kadam; Benoît Bletterie; Wolfgang Gawlik. 2017. "A Large Scale Grid Data Analysis Platform for DSOs." Energies 10, no. 8: 1099.
Energy system is undergoing remarkable changes due to many factors including increase use of renewables, environmental consideration and technological advancements. This demands for new tools and methods for its efficient and smooth operation. This work proposes distributed demand response application using Multi-Agent System (MAS) for improving voltage in distribution network at port city. Contract-Net-Protocol (CNP) based scheme was used for communication and coordination between agents. A co-simulation framework including power system simulator and agent environment was used to evaluate the proposed MAS based approach. A test network including variable and intermittent renewable generation sources (wind, pv), flexible loads (reefers), non-flexible loads was used to investigate the MAS based approach. Results show that MAS based approach is quite effective for demand response application.
Ntountounakis Manolis; Ishtiaq Ahmad; Kanellos Fotios; Peter Palensky; Wolfgang Gawlik; Javier Bajo; Zita Vale; Kasper Hallenborg; Ana Paula Rocha; Philippe Mathieu; Pawel Pawlewski; Elena Del Val; Paulo Novais; Fernando Lopes; Nestor D. Duque Méndez; Vicente Julián; Johan Holmgren. MAS Based Demand Response Application in Port City Using Reefers. Communications in Computer and Information Science 2017, 722, 361 -370.
AMA StyleNtountounakis Manolis, Ishtiaq Ahmad, Kanellos Fotios, Peter Palensky, Wolfgang Gawlik, Javier Bajo, Zita Vale, Kasper Hallenborg, Ana Paula Rocha, Philippe Mathieu, Pawel Pawlewski, Elena Del Val, Paulo Novais, Fernando Lopes, Nestor D. Duque Méndez, Vicente Julián, Johan Holmgren. MAS Based Demand Response Application in Port City Using Reefers. Communications in Computer and Information Science. 2017; 722 ():361-370.
Chicago/Turabian StyleNtountounakis Manolis; Ishtiaq Ahmad; Kanellos Fotios; Peter Palensky; Wolfgang Gawlik; Javier Bajo; Zita Vale; Kasper Hallenborg; Ana Paula Rocha; Philippe Mathieu; Pawel Pawlewski; Elena Del Val; Paulo Novais; Fernando Lopes; Nestor D. Duque Méndez; Vicente Julián; Johan Holmgren. 2017. "MAS Based Demand Response Application in Port City Using Reefers." Communications in Computer and Information Science 722, no. : 361-370.
The paper presents the results of determining parameters of an exponential load model at the low voltage side of a transformers. The input data was generated by continuous measurements in the resolution of one second over the period of one year. The identified parameters are clustered by different times of the day and weekdays. The found parameters are finally compared to parameters in the literature. Further research steps are discussed by presenting a combined approach for determining a ZIP model based on an exponential model. A future goal will be the usage of measurements currently available by smart metering applications which is discussed in the paper.
Jürgen Marchgraber; Evangelia Xypolytou; Irina Lupandina; Wolfgang Gawlik; Matthias Stifter. Measurement-based determination of static load models in a low voltage grid. 2016 IEEE PES Innovative Smart Grid Technologies Conference Europe (ISGT-Europe) 2017, 1 -6.
AMA StyleJürgen Marchgraber, Evangelia Xypolytou, Irina Lupandina, Wolfgang Gawlik, Matthias Stifter. Measurement-based determination of static load models in a low voltage grid. 2016 IEEE PES Innovative Smart Grid Technologies Conference Europe (ISGT-Europe). 2017; ():1-6.
Chicago/Turabian StyleJürgen Marchgraber; Evangelia Xypolytou; Irina Lupandina; Wolfgang Gawlik; Matthias Stifter. 2017. "Measurement-based determination of static load models in a low voltage grid." 2016 IEEE PES Innovative Smart Grid Technologies Conference Europe (ISGT-Europe) , no. : 1-6.
Reliable and efficient energy supply is based not only on local control but also on remote sensor data and measurements, making communication one of the important components. The increasing threat of possible attacks is the motivation behind the main purpose of the FUSE testbed—an experimental microgrid for smart grid research—to conduct experiments on smart grid security, grid optimization, stabilization and islanding. This work, after providing an insight of the current state of the art concerning research on microgrids, describes the FUSE experimental facility as well as first experiments including partial measurement equipment installation and data collection and analysis.
Evangelia Xypolytou; Joachim Fabini; Wolfgang Gawlik; Tanja Zseby. The FUSE testbed: establishing a microgrid for smart grid security experiments. e & i Elektrotechnik und Informationstechnik 2017, 134, 30 -35.
AMA StyleEvangelia Xypolytou, Joachim Fabini, Wolfgang Gawlik, Tanja Zseby. The FUSE testbed: establishing a microgrid for smart grid security experiments. e & i Elektrotechnik und Informationstechnik. 2017; 134 (1):30-35.
Chicago/Turabian StyleEvangelia Xypolytou; Joachim Fabini; Wolfgang Gawlik; Tanja Zseby. 2017. "The FUSE testbed: establishing a microgrid for smart grid security experiments." e & i Elektrotechnik und Informationstechnik 134, no. 1: 30-35.
This paper presents the advantages of the optimal DG placement during the operation stage of the radial distribution system. The method taken for optimal DG placement (ODGP) is considered from our previous work, which gives optimal locations based on Load Concentration Factor (LCF). Various cases of random DG placement (RDGP) are considered which are divided into two main categories. In first, the locations are varied and in second DG sizes are rotated on same locations found by LCF method. In all these cases, the total active power delivered by the DGs is kept same as for the case of ODGP. The load growth in network is considered to correspond to the future operational stage. A novel Voltage Quality Index (VQI) is proposed in this work which provides a straightforward method for quantifying the system's voltage quality status. Furthermore, two different scenarios, with and without a centralized voltage control algorithm, are considered for the comparison purpose. The advantages of ODGP in all these cases are highlighted by comparing the active power loss reduction, and voltage profile and quality improvement. The results showed that, in case of voltage problem, algorithm could improve voltage to a better limit, while keeping the losses reduced, in case of ODGP than RDGP cases.
Mohsin Shahzad; Wolfgang Gawlik; Peter Palensky. Voltage Quality Index based method to quantify the advantages of optimal DG placement. 2016 Eighteenth International Middle East Power Systems Conference (MEPCON) 2017, 759 -764.
AMA StyleMohsin Shahzad, Wolfgang Gawlik, Peter Palensky. Voltage Quality Index based method to quantify the advantages of optimal DG placement. 2016 Eighteenth International Middle East Power Systems Conference (MEPCON). 2017; ():759-764.
Chicago/Turabian StyleMohsin Shahzad; Wolfgang Gawlik; Peter Palensky. 2017. "Voltage Quality Index based method to quantify the advantages of optimal DG placement." 2016 Eighteenth International Middle East Power Systems Conference (MEPCON) , no. : 759-764.
Wolfgang Gawlik. Energie und Mobilität – Bestandsaufnahme und Entwicklungen. e & i Elektrotechnik und Informationstechnik 2017, 134, 113 -113.
AMA StyleWolfgang Gawlik. Energie und Mobilität – Bestandsaufnahme und Entwicklungen. e & i Elektrotechnik und Informationstechnik. 2017; 134 (1):113-113.
Chicago/Turabian StyleWolfgang Gawlik. 2017. "Energie und Mobilität – Bestandsaufnahme und Entwicklungen." e & i Elektrotechnik und Informationstechnik 134, no. 1: 113-113.
Christian Gererstorfer; Simon Stukelj; Georg Stix; Wolfgang Gawlik. Erratum zu: Schutz in Netzen mit leistungselektronischer Einspeisung – Betrachtungen zu Einflussgrößen auf die Distanzmessung von Distanzschutzgeräten. e & i Elektrotechnik und Informationstechnik 2017, 134, 123 -123.
AMA StyleChristian Gererstorfer, Simon Stukelj, Georg Stix, Wolfgang Gawlik. Erratum zu: Schutz in Netzen mit leistungselektronischer Einspeisung – Betrachtungen zu Einflussgrößen auf die Distanzmessung von Distanzschutzgeräten. e & i Elektrotechnik und Informationstechnik. 2017; 134 (1):123-123.
Chicago/Turabian StyleChristian Gererstorfer; Simon Stukelj; Georg Stix; Wolfgang Gawlik. 2017. "Erratum zu: Schutz in Netzen mit leistungselektronischer Einspeisung – Betrachtungen zu Einflussgrößen auf die Distanzmessung von Distanzschutzgeräten." e & i Elektrotechnik und Informationstechnik 134, no. 1: 123-123.