@incollection{SternerEckertGerhardtetal., author = {Sterner, Michael and Eckert, Fabian and Gerhardt, Norman and Henning, Hans-Martin and Palzer, Andreas}, title = {Speicherbedarf in der W{\"a}rmeversorgung}, series = {Energiespeicher - Bedarf, Technologien, Integration}, booktitle = {Energiespeicher - Bedarf, Technologien, Integration}, edition = {2. Auflage}, publisher = {Springer Vieweg}, address = {Berlin ; Heidelberg}, isbn = {978-3-662-48893-5}, doi = {10.1007/978-3-662-48893-5_4}, pages = {141 -- 168}, subject = {Energiespeicher}, language = {de} } @techreport{Brueckl, author = {Br{\"u}ckl, Oliver}, title = {Hemmnisse im Verteilnetzausbau und deren {\"U}berwindung}, publisher = {INA - Institut f{\"u}r Netz- und Anwendungstechnik GmbH}, address = {Waldm{\"u}nchen}, doi = {10.35096/othr/pub-6043}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:898-opus4-60438}, pages = {84}, abstract = {Die Bundesregierung hat ambitionierte Ausbaupfade f{\"u}r die Windenergie und Photovoltaik festgelegt. Allerdings gef{\"a}hrdet vor allem der Verteilnetzausbau und der Netzanschluss der Erneuerbare-Energien-Anlagen (EE-Anlagen) die Erreichung dieser hochgesteckten Ziele. In einem Gutachten im Auftrag der Fraktion von B{\"u}ndnis 90/DIE GR{\"U}NEN im Bayerischen Landtag identifiziert Prof. Dr.-Ing. Oliver Br{\"u}ckl die wesentlichen Hemmnisse f{\"u}r den beschleunigten Verteilnetzausbau und den Netzanschluss f{\"u}r EE-Anlagen und diskutiert L{\"o}sungsans{\"a}tze in folgenden Bereichen: Regulierungsrahmen f{\"u}r die Verteilnetzbetreiber, Genehmigungsverfahren von Netzausbauprojekten, Praxis der Netzintegration von EE-An lagen, Personalkapazit{\"a}ten, Beschaffung von Betriebsmitteln und Bau von Anlagen, Zertifizierungsprozess f{\"u}r den Netzanschluss von EE-Anlagen. Im Rahmen des Gutachtens wurden ca. 35 Interviews mit verschiedenen Stakeholdern gef{\"u}hrt: Netzbetreiber und Stadtwerke, Projektierer*innen, Herstellerindustrie, Verb{\"a}nde und Beh{\"o}rden.}, language = {de} } @article{BruecklDalissonStrohmayeretal., author = {Br{\"u}ckl, Oliver and Dalisson, Nils and Strohmayer, Bernhard and Haslbeck, Matthias}, title = {Spannungshaltungsmaßnahmen im Verteilungsnetz : Systemvergleich}, series = {EW : Magazin f{\"u}r die Energie-Wirtschaft}, volume = {113}, journal = {EW : Magazin f{\"u}r die Energie-Wirtschaft}, number = {6}, publisher = {VWEW-Energieverl.}, address = {Frankfurt am Main}, issn = {1619-5795}, pages = {66 -- 69}, abstract = {Verteilungsnetzbetreibern stehen mittlerweile viele Maßnahmen zur Behebung des Spannungsbandproblems zur Verf{\"u}gung. Innovative Konzepte wie der regelbare Ortsnetztransformator werden in vielen Pilotprojekten erprobt. Unklar ist jedoch noch, welche Maßnahmen beziehungsweise Kombinationen langfristig wirtschaftlich am g{\"u}nstigsten sind. Die Ostbayerische Technische Hochschule Regensburg untersucht daher in einem Forschungsprojekt verschiedene Maßnahmen, um sie unter wirtschaftlichen, technischen und energetischen Gesichtspunkten bewerten zu k{\"o}nnen. Der Beitrag untersucht am Beispiel des Netzmodells eines Dorfnetzes mit zahlreichen Photovoltaikanlagen unterschiedliche Szenarien f{\"u}r die Spannungshaltung, wobei u. a. Maßnahmen wie die Parallelverkabelung, das Einspeisemanagement durch Spitzenlastkappung, die Spannungs-Blindleistungsregelung durch die Erzeugungsanlagen sowie ein RONT (regelbarer Ortsnetztransformator) betrachtet werden. Dabei zeigt sich, dass es keine Maßnahme gibt, die in allen Belangen die g{\"u}nstigste L{\"o}sung ist. Es zeichnet sich jedoch ab, dass der RONT in vielen F{\"a}llen (abh{\"a}ngig vom Durchdringungsgrad) die g{\"u}nstigste oder zumeist eine g{\"u}nstige L{\"o}sung zur Erh{\"o}hung der Netzanschlusskapazit{\"a}t darstellt.}, language = {de} } @inproceedings{SchweibererRauchBrueckl, author = {Schweiberer, Philipp and Rauch, Johannes and Br{\"u}ckl, Oliver}, title = {Long-term analysis of industrial reactive power potentials with consideration of plant-internal grid restrictions using the example of an industrial plant in a distribution grid}, series = {NEIS 2022; Conference on Sustainable Energy Supply and Energy Storage Systems, 26-27 September 2022, Hamburg}, booktitle = {NEIS 2022; Conference on Sustainable Energy Supply and Energy Storage Systems, 26-27 September 2022, Hamburg}, editor = {Schulz, Detlef}, publisher = {VDE-Verlag}, address = {Berlin}, isbn = {978-3-8007-5983-5}, issn = {2510-6902}, pages = {51 -- 56}, abstract = {Since conventional generation plants provide a considerable share of reactive power but are gradually being shut down due to energy transition, leading to power deficits at the transmission grid level, new concepts for the supply of reactive power must be developed. As one possibility for the latter, industrial plants in the distribution grid are considered suitable, as their reactive power potentials can contribute to voltage maintenance and thus to a grid- or system-serving behavior. In this paper, the determination of reactive power potentials provided by industrial compensation systems (ICS) is presented. An industrial plant in the medium voltage grid, with three installed ICSs, is investigated. The potentials are determined and described based on their time characteristics, which provide information about the occurrence and distribution of inductive and capacitive potentials. A grid simulation of the investigated industrial grid is used to analyze the effects of retrieving the reactive power potentials regarding equipment utilizations and voltage limits.}, language = {en} } @inproceedings{KrausBrueckl, author = {Kraus, Hermann and Br{\"u}ckl, Oliver}, title = {Concept for the Use of an Automated Network-Planning in the Distribution Grid Level with Coordination of Various Grid Expansion Measures}, series = {NEIS 2019 : Conference on Sustainable Energy Supply and Energy Storage Systems, Hamburg 19.09.2019 - 20.09.2019}, booktitle = {NEIS 2019 : Conference on Sustainable Energy Supply and Energy Storage Systems, Hamburg 19.09.2019 - 20.09.2019}, editor = {Schulz, Detlef}, isbn = {978-3-8007-5152-5}, pages = {161 -- 165}, abstract = {In this thesis, a concept for the automated use of network planning processes, which is part of the decision support system developed in the framework of the EU project CrossEnergy, is presented. This publication focuses on the automatic processing of input data and subsequent network modeling as well as the coordination of network extension measures for the systematic solution of static voltage and current problems. Different variants are calculated in order to be able to compare the design technologies.}, language = {en} } @inproceedings{NonnErdelenPepplerWesseletal., author = {Nonn, Aida and Erdelen-Peppler, Marion and Wessel, Waldemar and Mahn, Denise}, title = {How reliable are the current testing procedures for the safety assurance against crack propagation in seamless gas pipelines}, series = {Proceedings of the ASME 2014 33rd International Conference on Ocean, Offshore and Arctic Engineering (OMAE2014), Volume 4A: Structures, Safety and Reliability, June 8-13, 2014, San Francisco, USA}, booktitle = {Proceedings of the ASME 2014 33rd International Conference on Ocean, Offshore and Arctic Engineering (OMAE2014), Volume 4A: Structures, Safety and Reliability, June 8-13, 2014, San Francisco, USA}, doi = {10.13140/2.1.3190.6567}, abstract = {The worldwide growing energy demand with the exploration of new gas fields has promoted the development of high toughness seamless pipeline steels which should sustain the increasing demands resulting from the complex loading situations. One of the most important prerequisites for safe installation and operation of long distance gas transmission pipelines is the detailed knowledge and characterization of their fracture performance for specific applications. However, recent industry experience has revealed concerns related to the limitations and reliability of current test methods for brittle-to-ductile transition evaluation. Regarding the transition temperature evaluation, the critical issues involve Drop-Weight Tear Testing (DWTT) and full-scale West-Jefferson (WJ) test applied to the smaller pipes with diameter less than 500mm. The DWTT leads frequently to invalid results in terms of abnormal fracture appearance and inverse fracture occurrence. It is still not clear if this behavior is only owed to a testing effect, which material characteristics cause it and how far it reflects the full-scale behavior. Similar observations were made for the West-Jefferson tests, which could not be assessed in the standard manner either. Again, the question was towards testing effects and the behavior of the pipeline transporting gaseous media remains unanswered. Therefore, this paper aims at identifying open questions on basis of a literature study and own experimental results and showing possible ways forward in demonstrating safety in design against propagating fracture.}, language = {en} } @inproceedings{NonnParedesNordhagenetal., author = {Nonn, Aida and Paredes, Marcelo and Nordhagen, H. O. and Munkejord, S. T. and Wierzbicki, Tomasz}, title = {Challenges in fluid-structure modeling of crack propagation and arrest in modern steel pipelines}, series = {14th International Congress on Fracture (ICF14), 18-23 June 2017, Rhodes, Greece}, booktitle = {14th International Congress on Fracture (ICF14), 18-23 June 2017, Rhodes, Greece}, pages = {1351 -- 1352}, language = {en} } @inproceedings{KarbasianGrossWeegeNonnetal., author = {Karbasian, H. and Groß-Weege, J. and Nonn, Aida and Zimmermann, S. and Kalwa, Christoph}, title = {Assessment of collapse resistance of UOE pipes - comparison of full-scale and ring collapse tests}, series = {Proceedings of the 10th International Pipeline Conference 2014 (IPC 2014), September 29 - October 3, 2014, Calgary, Alberta, Canada}, booktitle = {Proceedings of the 10th International Pipeline Conference 2014 (IPC 2014), September 29 - October 3, 2014, Calgary, Alberta, Canada}, language = {en} } @inproceedings{NonnKalwa, author = {Nonn, Aida and Kalwa, Christoph}, title = {Analysis of dynamic ductile fracture propagation in pipeline steels}, series = {6th Pipeline Technology Conference (2013), Ostend, Belgium}, booktitle = {6th Pipeline Technology Conference (2013), Ostend, Belgium}, doi = {10.13140/2.1.4370.3046}, abstract = {Analysis of dynamic ductile fracture propagation in pipeline steels: a damage-T IS A WELL-ESTABLISHED fact that the successful application of new generation of high-strength steel grades for long-distance gas transmission depends strongly on full understanding and appropriate characterization of fracture resistance. A damage mechanics approach has found to be a very promising tool in supporting the experimental characterization of ductile fracture propagation. The major advantage of this approach lies in the consideration of the influence of local stress and strain variables on the damage evolution and thus its capability to describe the fracture resistance of the pipelines with different stress triaxiality level by using the same set of parameters. However, the wider application of this approach has been limited due to the issues such as reliable determination of input parameters and required material properties, mesh size dependence, etc.. The objective of this paper is to characterize dynamic ductile fracture resistance of X65 and X80 pipeline materials and to demonstrate the potential of damage mechanics approach for the simulation of dynamic fracture propagation by using two damage models: (1) Cohesive Zone (CZ) model and (2) Gurson-Tvergaard-Needleman (GTN) model. In the first step, results from quasi-static and dynamic tensile tests are used to describe plasticity in terms of flow curves. The calibration of input parameters for both models is performed by using the load-deformation curves from quasi-static tests on non-standard drop-weight tear (DWT) specimens with pre-fatigued crack. b. In the next step, estimated damage model parameters are verified by means of the dynamic tests on the pressed and Chevron notch DWT specimens. Different amounts of crack growth are established by varying the drop height. The experimental fracture resistance is quantified in terms of J-integral at specific crack length. The numerical results are evaluated with respect to global load-deformation and fracture resistance behavior. Furthermore, damage simulations are applied for quantification of local stress conditions in order to identify the major factors controlling the crack propagation. The results reported here serve as a basis for better understanding of fracture performance in dependences of geometry and material properties.}, language = {en} } @inproceedings{NonnErdelenPepplerWesseletal., author = {Nonn, Aida and Erdelen-Peppler, Marion and Wessel, Waldemar and Harksen, Silke and Mahn, Denise}, title = {How to assure fracture-propagation control for seamless gas pipelines?}, series = {Proceedings of the 2014 10th International Pipeline Conference (IPC2014), Volume 3: Operations, Monitoring, and Maintenance, Materials and Joining, September 29-October 3, 2014, Calgary, Canada}, booktitle = {Proceedings of the 2014 10th International Pipeline Conference (IPC2014), Volume 3: Operations, Monitoring, and Maintenance, Materials and Joining, September 29-October 3, 2014, Calgary, Canada}, doi = {10.1115/IPC2014-33169}, abstract = {Fracture propagation control in gas transmission gas pipelines belongs to the major design requirements for safe operation at high internal pressures. However, the current tests such as Drop-Weight-Tear Test (DWTT) and full-scale West-Jefferson (WJ) test reach the limits of their applicability with respect to transition temperature evaluation for seamless quenched and tempered small diameter pipes reflecting nowadays alloying concepts related to mechanical properties. Hereby, different geometry and material effects are evident which might lead to misinterpretation and unreliability of testing results. This paper aims to discuss open issues addressed in the literature and in own experimental findings with respect to reliability and transferability of testing methods, fracture parameters and their representativeness of seamless quenched and tempered pipeline behavior. By applying damage mechanics approach, it is possible to quantify the prevailing stress state and thus to understand the mechanisms controlling specific fracture appearance (ductile or brittle). Furthermore, studies were performed with objective to quantify the effect of different parameters (geometry, material and loading) on the fracture performance of the pipeline. The results from these investigations will serve as a basis for a safe pipeline design against propagating fracture.}, language = {en} } @inproceedings{NonnKalwa, author = {Nonn, Aida and Kalwa, Christoph}, title = {Simulation of ductile crack propagation in high-strength pipeline steel using damage models}, series = {9th International Pipeline Conference 2012 (IPC 2012), Calgary, Canada}, booktitle = {9th International Pipeline Conference 2012 (IPC 2012), Calgary, Canada}, doi = {10.1115/IPC2012-90653}, pages = {7}, abstract = {The performance of engineering design of high-strength steel pipelines has revealed the necessity to revise current design procedures. Therefore, an improved and detailed comprehension of fracture mechanisms and development of failure prediction tools are required in order to derive new design criteria. In last decades the most successful failure prediction tools for steel structures subjected to various type of loading can be encountered in the field of damage mechanics. This paper aims to describe ductile fracture behavior of high-strength steel pipelines by applying three different damage models, Gurson-Tvergaard-Needelman (GTN), Fracture Locus Curve (FLC) and Cohesive Zone (CZ). These models are evaluated regarding their capability to estimate ductile crack propagation in laboratory specimens and linepipe components without adjusting the calibrated parameters. It can be shown that appropriate parameter sets can be identified to reproduce load-deformation and fracture resistance curves accurately. The strain rate effect on the fracture behavior is examined by dynamic tests on the BDWT specimens. Finally, the shortcomings of the applied models are pointed out with the reference to possible extensions and modifications.}, language = {en} } @inproceedings{VoellingNonnSchneider, author = {V{\"o}lling, Alexander and Nonn, Aida and Schneider, Ingo}, title = {Anwendung des Koh{\"a}sivzonenmodells zur Abbildung von duktilem dynamischen Rissfortschritt in Gasfernleitungen}, series = {45. Tagung des AK Bruch, Berlin, Germany}, booktitle = {45. Tagung des AK Bruch, Berlin, Germany}, pages = {253 -- 262}, subject = {Ferngasleitung}, language = {de} } @inproceedings{NonnWesselSchmidt, author = {Nonn, Aida and Wessel, Waldemar and Schmidt, Tanja}, title = {Application of finite element analysis for assessment of fracture behavior of modern high toughness seamless pipeline steels}, series = {23rd International Society of Offshore and Polar Engineering 2013 (ISOPE 2013), Anchorage, USA}, booktitle = {23rd International Society of Offshore and Polar Engineering 2013 (ISOPE 2013), Anchorage, USA}, doi = {10.13140/2.1.4239.2322}, abstract = {Fracture behavior of seamless pipeline material X65Q acc. to API 5L has been studied both experimentally and numerically at different loading conditions (quasi-static vs. dynamic) and temperatures. The recent findings have shown difficulties in applying well established methods for determination of transition behavior or prediction of ductile crack arrest for the new generation of high-toughness steels. The irregular fracture performance (e.g. so-called "abnormal inverse fracture" appearance, significant scattering in ductile-to-brittle-transition-temperature region, etc.) suggests that the influence of pipe dimensions, loading parameters, crack initiation resistance as well as testing procedure on the fracture behavior has been neither understood nor properly described. This work aims to shed light on these questions regarding the applicability of conventional methods and to better illuminate most relevant parameters affecting fracture behavior of high toughness steels. To achieve this goal, experimental data basis for analysis of fracture behavior in transition and upper shelf regime has been established by conducting quasi-static fracture mechanics tests and dynamic tests on Battelle Drop Weight Tear (BDWT or DWT) specimens at different temperatures. The evaluation of obtained test results in upper shelf has been additionally complemented by numerical simulation of damage behavior. The results highlight the influence of stress conditions on fracture behavior with reference to pipe dimensions and loading conditions and, subsequently, may be used as a basis for revision of existing design methods.}, subject = {Rissfortschritt}, language = {en} } @inproceedings{KofianiNonnWierzbickietal., author = {Kofiani, Kirki and Nonn, Aida and Wierzbicki, Tomasz and Kalwa, Christoph and Walters, Carey}, title = {Experiments and fracture modeling of high-strength pipelines for high and low stress triaxiality}, series = {22nd International Society of Offshore and Polar Engineering 2012 (ISOPE 2012), Rhodes, Greece, June 2012}, booktitle = {22nd International Society of Offshore and Polar Engineering 2012 (ISOPE 2012), Rhodes, Greece, June 2012}, abstract = {This paper provides results from a comprehensive study on mechanical characterization of high-strength pipeline steel, grade X100 using experimental and numerical methods. The material was characterized for anisotropic plasticity, fracture initiation for various states of stress, (pre-cracked) fracture toughness and uncracked ductility. The experimental program included tests on flat butterfly-shaped, central hole, notched and circular disk specimens for low stress triaxiality levels; as well as tests on round notched bar specimens and SENT fracture mechanics tests, for high values of stress triaxiality. This program covered a wide range of stress conditions and demonstrated its effect on the material resistance. Parallel to the experimental study, detailed numerical investigations were carried out to simulate all different experimental tests. Using an inverse method, a 3-parameter calibration was performed on the Modified Mohr-Coulomb (MMC) fracture model. Subsequently, the predictive capabilities of the MMC were evaluated by the comparison to the fracture toughness tests results, used extensively in the pipeline industry. The capabilities of the MIT fracture model have been demonstrated on an example of high strength offshore steel, X100. The outcome of this study was not only to provide, the overall characterization of the fracture behavior of this material as an example, but also to present the methodology on how to use the MMC model as a practical tool in pipeline design.}, language = {en} } @inproceedings{NonnKalwa, author = {Nonn, Aida and Kalwa, Christoph}, title = {Failure modeling of pipeline X100 Material in temperature transition region}, series = {22nd International Society of Offshore and Polar Engineering 2012 (ISOPE 2012), Rhodes, Greece}, booktitle = {22nd International Society of Offshore and Polar Engineering 2012 (ISOPE 2012), Rhodes, Greece}, abstract = {This paper focuses on the characterization of the fracture performance of X100 material in transition temperature region using both experimental and numerical methods. The ductile fracture has been analyzed using tests on round notched bar specimens and standard fracture mechanics tests performed at room temperature. In previous publications the damage model Gurson-Tvergaard-Needleman (GTN) has been applied and verified by existing experimental data to describe ductile fracture behavior. The brittle fracture and the fracture in temperature transition region have been studied by means of deep and shallow notched SENB specimens at two different temperatures T=- 80°C and -40°C. Besides elastic-plastic analyses to quantify constraint levels for different initial crack configurations at the onset of cleavage fracture, the brittle failure has been described using modified Beremin model. The influence of the stable crack growth on the cleavage failure probability in temperature transition region has been captured by coupling the ductile fracture model (GTN) with the modified Beremin model. Finally, examples have been presented for the practical application of the numerical results on the fracture assessment of the flawed high-strength pipelines.}, language = {en} } @inproceedings{NonnKalwa, author = {Nonn, Aida and Kalwa, Christoph}, title = {The effect of microstructure, strain hardening and strain rate on the fracture behavior of high strength pipeline steels}, series = {2nd International Conference on Material Modelling (ICMM2), 31th August - 2nd September, 2011 at Mines Paris Tech, France}, booktitle = {2nd International Conference on Material Modelling (ICMM2), 31th August - 2nd September, 2011 at Mines Paris Tech, France}, language = {en} } @inproceedings{NonnKalwa, author = {Nonn, Aida and Kalwa, Christoph}, title = {Application of damage mechanics approach for crack propagation in pipeline}, series = {19th Biennial Joint Technical Meeting (JTM) on Pipeline Research, April 29 - May 3, 2013, Sydney, Australia}, booktitle = {19th Biennial Joint Technical Meeting (JTM) on Pipeline Research, April 29 - May 3, 2013, Sydney, Australia}, language = {en} } @inproceedings{NonnKalwa, author = {Nonn, Aida and Kalwa, Christoph}, title = {Application of probabilistic fracture mechanics for safety assessment of longitudinally welded linepipes}, series = {6th Pipeline Technology Conference (2013), Ostend, Belgium}, booktitle = {6th Pipeline Technology Conference (2013), Ostend, Belgium}, language = {en} } @techreport{NeidhartLerchWiesingeretal., author = {Neidhart, Thomas and Lerch, Maximilian and Wiesinger, Doris and Zrenner, Louis}, title = {Kompakte {\"U}bertragungsleitungen f{\"u}r hohe Gleichspannungen: Langzeituntersuchungen an einer erdverlegten Versuchsanlage}, doi = {10.35096/othr/pub-2173}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:898-opus4-21730}, pages = {62, 58}, abstract = {Durch den Ausstieg aus der Verstromung fossiler Energietr{\"a}ger und der daraus resultierenden dezentralen Stromerzeugung ist ein Aus- bzw. Umbau des deutschen {\"U}bertragungsnetzes erforderlich. Weil aus der dezentralen Energieerzeugung große Trassenl{\"a}ngen resultieren, welche bei Wechselstrom zu Blindleistungsproblematiken f{\"u}hren, wird dort vermehrt auf Hochspannungs-Gleichstrom-{\"U}bertragung zur{\"u}ckgegriffen. Im Rahmen des Forschungsprojekts DC CTL DBI (direct current compact transmission line - directly buried investigastions) wurde ein gasisolierte HG{\"U}-Leiter (GIL) erdverlegt und bei st{\"a}ndigem Monitoring {\"u}ber umfangreiche Sensorik einem Langzeitversuch unterzogen. Anstelle einer klassischen Sandbettung kam ein zeitweise fließf{\"a}higer, selbstverdichtender Verf{\"u}llbaustoff (ZFSV) zum Einsatz. Somit k{\"o}nnen Sch{\"a}den an der {\"U}bertragungsleitung infolge Verdichtungsaufwand vermieden und gleichzeitig bessere Bodeneigenschaften hinsichtlich der W{\"a}rme- und Wassertransportprozesse erreicht werden.}, language = {de} } @incollection{SternerStadler, author = {Sterner, Michael and Stadler, Ingo}, title = {Energiespeicher im Wandel der Zeit}, series = {Energiespeicher - Bedarf, Technologien, Integration}, booktitle = {Energiespeicher - Bedarf, Technologien, Integration}, edition = {2. Auflage}, publisher = {Springer Vieweg}, address = {Berlin ; Heidelberg}, isbn = {978-3-662-48893-5}, doi = {10.1007/978-3-662-48893-5_1}, pages = {3 -- 24}, subject = {Energiespeicher}, language = {de} }