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Trafikverket operates about 12000 Switches and crossings (SnCs) of which 6800 are equipped with an electrical heating system of 10−30kW power to keep SnCs functional throughout the winters by keeping them free of Snow/Ice. The energy consumption is approximately 200−130GWh/year costing approximately 10−15 million Euros annually. Electricity demand is continuously rising in Sweden and if coupled with unpredictable events can highly impact the grid energy mix and electricity prices which can lead to a higher operating carbon footprint & expenses. This master thesis work is developed through a couple of research programs to investigate the power usage in wayside objects. Currently, work is in progress to make the wayside objects ‘smart’ so that they can operate fully autonomously with two objectives to reduce the overall power consumption and obtain it from local energy resources. Mathematical modeling of unsteady close contact melting of rectangular Ice/Snow blocks of different volumes on the horizontal surfaces has been solved using numerical methods to calculate the melting time and power requirement. A parametric study has been done for various sizes, and initial & hot surface temperatures. Further, using ANSYS Fluent, CFD simulations have been performed to calculate the heat transfer rate from the Rail body for various combinations of heat source & ambient temperature, and wind speeds. These results shall help to devise a control strategy for the dynamic power supply which can help to optimize the power consumption. Finally, evaluating the renewable resources potential; ground source heat pumps using borehole U-pipes appear to be the best option which can drastically reduce the electricity requirement for the optimized heating power requirement. Most of Sweden has granite bedrock which is one of the reasons for the successful deployment of heat pumps. It’s definitely worth expanding its usage in other sectors as well like Railways. / Trafikverket driver cirka 12 000 spårväxlar och spårkorsningar varav 6 800 är utrustade med ett elektriskt värmesystem på 10 - 30kW effekt för att hålla växlar och korsningar funktionella under hela vintrarna genom att hålla dem fria från snö/is. Energiförbrukningen är cirka 200-130 GW h/år och kostar cirka 10-15 miljoner euro per år. Efterfrågan på el ökar kontinuerligt i Sverige och kan i kombination med oförutsägbara händelser i hög grad påverka nätets energimix och elpris vilket i sin tur kan leda till ett högre koldioxidavtryck och högre driftskostnader. Detta examensarbete utvecklades genom ett par forskningsprogram med fokus på strömförbrukningen i järnvägssystemet. Just nu pågår ett arbete med att göra järnvägssystemet "smart" så att det kan fungera helt automatiskt med två mål: att minska den totala energiförbrukningen och få den från lokala energiresurser. Kontaktsmältning av rektangulärt is/snö-block av olika volymer på horisontella ytor har lösts med hjälp av numeriska metoder för att beräkna smälttid och effektbehov. En parametrisk studie har gjorts för olika storlekar och initiala och varma yttemperaturer. Vidare, med hjälp av ANSYS Fluent, har CFD-simuleringar utförts för att beräkna värmeöverföringshastighet från järnvägsspåret för olika kombinationer av värmekälla och omgivning temperatur och vindhastigheter. Dessa resultat ska bidra till att utforma en styrstrategi för den dynamiska strömförsörjningen som kan bidra till att optimera strömförbrukningen. Slutligen, för att utvärdera potentialen för förnybara resurser, verkar bergvärmepumpar som använder borrhåls U-rör vara det bästa alternativet som drastiskt kan minska elbehovet för det optimerade värmeeffektbehovet. Större delen av Sverige har berggrund av granit vilket är en av anledningarna till den framgångsrika utbyggnaden av värmepumpar. Det är definitivt värt att utöka användningen i andra sektorer också som järnvägar.

New decline curve models have been developed to overcome the boundary-dominated flow assumption of the basic Arps’ models, which restricts their application in ultra-low permeability reservoirs exhibiting long-duration transient flow regimes. However, these new decline curve analysis (DCA) methods are still based only on production rate data, relying on the assumption of stable flowing pressure. Since this stabilized state is not reached rapidly in most cases, the applicability of these methods and the reliability of their solutions may be compromised. In addition, production performance predictions cannot be disassociated from the existing operation constraints under which production history was developed. On the other hand, DCA is often carried out without a proper identification of flow regimes. The arbitrary application of DCA models regardless of existing flow regimes may produce unrealistic production forecasts, because these models have been designed assuming specific flow regimes. The main purpose of this study was to evaluate the possible benefits provided by including flowing pressures in production decline analysis. As a result, it have been demonstrated that decline curve analysis based on pressure-normalized rates can be used as a reliable production forecasting technique suited to interpret unconventional wells in specific situations such as unstable operating conditions, limited availability of production data (short production history) and high-pressure, rate-restricted wells. In addition, pressure-normalized DCA techniques proved to have the special ability of dissociating the estimation of future production performance from the existing operation constraints under which production history was developed. On the other hand, it was also observed than more consistent and representative flow regime interpretations may be obtained as diagnostic plots are improved by including MBT, pseudovariables (for gas wells) and pressure-normalized rates. This means that misinterpretations may occur if diagnostic plots are not applied correctly. In general, an improved forecasting ability implies greater accuracy in the production performance forecasts and more reliable reserve estimations. The petroleum industry may become more confident in reserves estimates, which are the basis for the design of development plans, investment decisions, and valuation of companies’ assets.

Neue elektrische Antriebskonzepte ermöglichen es, eine hohe Funktionalität in einem eingeschränkten Bauraum unterzubringen. Damit steigt auch in der Landwirtschaft das Interesse an elektrischen Antrieben. Die Projektgruppe Elektrische Maschinen und Antriebe der HTW Dresden beteiligt sich mit der TU Dresden an einem Projekt, bei dem beginnend mit der elektrisch angetriebenen Dreschtrommel umfassend an einem Mähdrescher untersucht wird, wie diese Antriebe in einzelne Funktionselemente integriert werden können. Neben der Auslegung der Antriebe werden Verfahren erarbeitet, die Verluste im Motor mit hoher Genauigkeit zu berechnen. So können in Zukunft passgenaue Kühlkonzepte für diese Antriebstechnik entwickelt werden. Anforderungen gerade im Bereich der Elektromobilität fordern den Blick für neue Materialien, deren elektromagnetisches und thermisches Verhalten werden in ihrem Einfluss auf die Erwärmung untersucht. Analytische und kombinierte Berechnungsmethoden in 2D-FEM gestatten die vereinfachte Rechnung unter Berücksichtigung von Grundwelle und entstehenden Harmonischen zu qualifizieren. Verlustberechnungen aus der transienten FEM-Rechnung ermöglichen diese Verbesserung. Die Methode wird am Beispiel der elektrischen Dreschtrommel mit den berechneten Verlustverteilungen beschrieben. Neue Methoden der 3D-FEM, wie sie die Software Ansys bietet, werden für die Nutzung von Einflüssen der Wirbelstromeffekte und in Auswertung für die Segmentierung von Permanentmagneten dargestellt. Die exemplarisch gewonnenen Erkenntnisse liefern einen Beitrag für weitere Schneidwerksantriebe am Mähdrescher, aber auch darüber hinaus in Projekten mit Herstellern elektrischer Maschinen. / New concepts for electrical drives make it possible to put a high functionality into a restricted structural form. Thereby the interest in electrical drives increases also in the farming. The project team Electrical machines and drives of the HTW Dresden participates together with the TU Dresden in a project, where starting with the electrically driven threshing cylinder is comprehensively examined at a combine harvester, how these drives can be integrated into single function elements. Besides the dimensioning of the drives are developed methods to calculate losses in the engine with high precision. So custom-fit cooling concepts can be developed for this drive technology in future. Requirements just in the area of the electric mobility call looking for new materials, whose electromagnetic and thermic behavior are examined in her influence on the warming. Analytical and combined computation methods in 2D-FEM allow the simplified calculation under consideration of the fundamental wave and the arising harmonic ones. Loss calculations by means of the transient FEM calculation make possible this improvement. The method is described at the example of the electrical threshing cylinder with the calculated loss distributions. New methods of the 3D-FEM, as the software of Ansys offers, are presented for the use of influences of the eddy current effects and in evaluation for the segmentation of permanent magnets. The exemplarily got knowledge provides a contribution for further cut header drives at the combine but also furthermore in projects together with manufacturers of electrical machines.

[pt] Colunas de aço estaiadas e protendidas são conhecidas como excelente solução em escoramento de grandes estruturas, como colunas de coberturas de lonas tensionadas, etc. Este trabalho apresenta uma série de ensaios experimentais tridimensionais em escala real desenvolvidos para determinação do comportamento estrutural de colunas de aço estaiadas e protendidas. Foram estudadas as variações no nível de protensão e na rigidez dos estais, além de descrever como os ensaios experimentais das três colunas de aço estaiadas são realizados: compreendendo os materiais utilizados; um novo sistema de medição de força nos estais; os passos e dificuldades na montagem das três colunas e o sistema de protensão aplicado. Existem alguns parâmetros que influenciam diretamente na resistência dessas colunas estaiadas, como por exemplo, a altura da coluna, o diâmetro externo, entre outros. Devido ao comportamento complexo deste tipo de colunas e ao grande esforço computacional para simulação do comportamento estrutural, através de uma análise paramétrica, optou-se por utilizar um projeto de experimentos junto com redes neurais a fim de extrapolar e obter novos resultados para carga crítica do sistema estrutural sem a necessidade de análise por programas de elementos finitos. De forma a complementar a tese, realizou-se um estudo do comportamento do sistema estrutural sujeito a ações dinâmicas através do programa de elementos finitos ANSYS com o objetivo de determinar as frequências naturais associadas aos seus modos de vibração. Também foi estudada a aplicação de um carregamento súbito para determinação do fator de amplificação dinâmico da coluna de aço estaiada e protendida. / [en] Prestressed steel columns are known as an efficient structural solution for great variety of temporary or permanent supporting systems for large span spatial frames and tensile surface structures. This work presents of full-scale three-dimensional tests carriedout for the assessment of structural behaviour of prestressed stayed steel columns. It was studied the effect prestress force level, stiffness of column braces and stays. Test setup and a new force measuring system for the column stays is fully described. Prestressed stayed steel columns have their strength dependant of parameters like: length, hollow section diameter, brace length and stiffness and axial stiffness of stays. Due to the complex behaviour of such columns that demands great computational effort for numerical simulations required for a parametric analysis it was used an experiment design tool coupled with neural network techniques employed to generate new data for the prestressed column buckling load. A study of the dynamic behaviour of prestressed columns using the finite element package ANSYS was carried-out in order to determine the column natural frequencies and their associated vibration modes. It was also studied the application of sudden loads to determine the dynamic amplification factor of this type of prestressed stayed steel column.

Neue elektrische Antriebskonzepte ermöglichen es, eine hohe Funktionalität in einem eingeschränkten Bauraum unterzubringen. Damit steigt auch in der Landwirtschaft das Interesse an elektrischen Antrieben. Die Projektgruppe Elektrische Maschinen und Antriebe der HTW Dresden beteiligt sich mit der TU Dresden an einem Projekt, bei dem beginnend mit der elektrisch angetriebenen Dreschtrommel umfassend an einem Mähdrescher untersucht wird, wie diese Antriebe in einzelne Funktionselemente integriert werden können. Neben der Auslegung der Antriebe werden Verfahren erarbeitet, die Verluste im Motor mit hoher Genauigkeit zu berechnen. So können in Zukunft passgenaue Kühlkonzepte für diese Antriebstechnik entwickelt werden. Anforderungen gerade im Bereich der Elektromobilität fordern den Blick für neue Materialien, deren elektromagnetisches und thermisches Verhalten werden in ihrem Einfluss auf die Erwärmung untersucht. Analytische und kombinierte Berechnungsmethoden in 2D-FEM gestatten die vereinfachte Rechnung unter Berücksichtigung von Grundwelle und entstehenden Harmonischen zu qualifizieren. Verlustberechnungen aus der transienten FEM-Rechnung ermöglichen diese Verbesserung. Die Methode wird am Beispiel der elektrischen Dreschtrommel mit den berechneten Verlustverteilungen beschrieben. Neue Methoden der 3D-FEM, wie sie die Software Ansys bietet, werden für die Nutzung von Einflüssen der Wirbelstromeffekte und in Auswertung für die Segmentierung von Permanentmagneten dargestellt. Die exemplarisch gewonnenen Erkenntnisse liefern einen Beitrag für weitere Schneidwerksantriebe am Mähdrescher, aber auch darüber hinaus in Projekten mit Herstellern elektrischer Maschinen. / New concepts for electrical drives make it possible to put a high functionality into a restricted structural form. Thereby the interest in electrical drives increases also in the farming. The project team Electrical machines and drives of the HTW Dresden participates together with the TU Dresden in a project, where starting with the electrically driven threshing cylinder is comprehensively examined at a combine harvester, how these drives can be integrated into single function elements. Besides the dimensioning of the drives are developed methods to calculate losses in the engine with high precision. So custom-fit cooling concepts can be developed for this drive technology in future. Requirements just in the area of the electric mobility call looking for new materials, whose electromagnetic and thermic behavior are examined in her influence on the warming. Analytical and combined computation methods in 2D-FEM allow the simplified calculation under consideration of the fundamental wave and the arising harmonic ones. Loss calculations by means of the transient FEM calculation make possible this improvement. The method is described at the example of the electrical threshing cylinder with the calculated loss distributions. New methods of the 3D-FEM, as the software of Ansys offers, are presented for the use of influences of the eddy current effects and in evaluation for the segmentation of permanent magnets. The exemplarily got knowledge provides a contribution for further cut header drives at the combine but also furthermore in projects together with manufacturers of electrical machines.

Numerické metody inverzní Laplaceovy transformace (NILT) se staly důležitou částí numerické sady nástrojů praktikujících a výzkumných pracovníků v mnoha vědeckých a inženýrských oborech, zejména v aplikované elektrotechnice. Techniky NILT zejména pomáhají při získávání výsledků simulací v časové oblasti v různých aplikacích. Příkladem jsou řešení obyčejných diferenciálních rovnic, které se objevují např. při analýze obvodů se soustředěnými parametry, nebo řešení parciálních diferenciálních rovnic objevujících se v systémech s rozprostřenými parametry, např. při zkoumání problematiky integrity signálů. Obecně platí, že většina dostupných 1D NILT metod je velmi specifická, tj. funguje dobře na několika typech funkcí a tudíž na omezeném počtu aplikací; Cílem této práce je podrobně se věnovat těmto numerickým metodám, vývoji univerzálních metod NILT a jejich rozšíření na multidimenzionální NILT, které mohou pokrývat širokou oblast aplikací a mohly by poskytnout praktický mechanism pro efektivnější způsob analýzy a simulace v časové oblasti. Myšlenky výzkumu jsou prezentovány v rámci diskusí nad širokou škálou případových studií a aplikací; Například metody NILT se používají při řešení přenosových vedení, včetně vícevodičových, a dokonce i při řešení slabě nelinárních obvodů při použití NILT více proměnných. Pomocí metody NILT mohou být s výhodou uvažovány parametry prvků závislé na kmitočtu a prvky necelistvých řádů v jejich příslušných modelech mohou být zahrnuty velmi přesným a jednoduchým způsobem.