Advanced search

Showing result 1 - 5 of 6 swedish dissertations matching the above criteria.

2. 1. Stability of Low-Frequency AC Railways : Models and Transient Stability

   Author : John Laury; Lars Abrahamsson; Math Bollen; Pablo Arboleya; Luleå tekniska universitet; []
   Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Electric Power Engineering; Elkraftteknik;

   Abstract : Low-frequency AC railway grids are unique in the sense that a only few countries around the world uses them, still however, they are an important parts of their countries infrastructures. Due to the usage of a dierent frequency than the public grid of the country, conversion of frequency is needed for the interconnection. READ MORE

4. 2. Stochastic Planning of Smart Electricity Distribution Networks

   Author : Manuel Alejandro Alvarez Perez; Sarah K. Rönnberg; Math Bollen; Jin Zhong; Luleå tekniska universitet; []
   Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Electric Power Engineering; Elkraftteknik;

   Abstract : The penetration of intermittent Distributed Generation (DG) brought additional uncertainty to the system operation and planning. To cope with uncertainties the Distribution System Operator (DSO) could implement several strategies. READ MORE

5. 3. On the hosting capacity of distribution networks for solar power

   Author : Enock Mulenga; Math Bollen; Nicholas Etherden; Luis (Nando) Ochoa; Luleå tekniska universitet; []
   Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Aleatory; distribution networks; epistemic; hosting capacity; overvoltage; solar power; stochastic; Electric Power Engineering; Elkraftteknik;

   Abstract : The future will bring changes in energy production and consumption that will affect the performance of electricity distribution networks. Electric vehicle charging will increase consumption; the installation of solar photovoltaic (PV) units will increase production. Both will change the energy flow and affect the power quality. READ MORE

6. 4. Mechanistic-Empirical Modelling of Flexible Pavement Performance : Verifications Using APT Measurements

   Author : Abubeker W. Ahmed; Sigurdur Erlingsson; Hervè Di Benedetto; Statens väg- och transportforskningsinstitut; []
   Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Performance; Deformation; Model not math ; Rutting wheel ; Viscoelasticity; Elasticity; Axle load; Flexible pavement; Laboratory not an organization ; Test; Thesis; Heavy vehicle simulator; Wheel tracking test; 32 Road: Pavement design; 32 Road: Pavement design; Transportvetenskap; Civil and Architectural Engineering;

   Abstract : Mechanistic-Empirical  (M-E)  pavement  design  procedures  are  composed  of  a  reliable  response model to estimate the state of stress in the pavement and distress models in order to predict the different types of pavement distresses due to the prevailing traffic and environmental conditions. One of the main objectives of this study was to develop a response model based on multilayer elastic  theory   (MLET)  with  improved  computational  performance  by   optimizing  the   time consuming parts of the MLET processes. READ MORE

7. 5. Weld Pool Simulations

   Author : Marcus Edstorp; Högskolan Väst; []
   Keywords : NATURVETENSKAP; NATURAL SCIENCES; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Arc Welding; Weld Pool; Multiphysics Simulations; Moving Boundaries; Free Surfaces; Mesh Motion; Two-Phase Flow; Incompressible Flow; Electromagnetics; Finite Element Methods; Applied mathematics; Tillämpad matematik; Manufacturing engineering; Produktionsteknik; Manufacturing and materials engineering; Produktions- och materialteknik; Arc Welding; Weld Pool; Multiphysics Simulations; Moving Boundaries; Free Surfaces; Mesh Motion; Two-Phase Flow; Incompressible Flow; Electromagnetics; Finite Element Methods;

   Abstract : This investigation is devoted to the study of welding and its effect on the workpiece, focusing on the thermo and fluid dynamical phenomena occuring during a autogenous or nonautogenous arc fusion welding process. Its aim is to simulate the behaviour of the weld pool and analyze the consequence of the solid-liquid phase change, thus obtaining a methodology for predicting the appearance of weld defects related to solidification and cooling. READ MORE