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Showing result 1 - 5 of 102 swedish dissertations matching the above criteria.

2. 1. Polyethylene/metal oxide nanocomposites for electrical insulation in future HVDC-cables : probing properties from nano to macro

   Author : Love Pallon; Ulf Gedde; Mikael Hedenqvist; Richard Olsson; Alun Vaughan; KTH; []
   Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Nanocomposites; polyethylene; particle dispersion; high voltage direct current cables; HVDC; HVDC insulation; MgO; intermodulation electrostatic force microscopy; ptychography; electrical tree; Nanokompositer; polyeten; HVDC; HVDC-kabel; HVDC-isolering; MgO; elektrisk isolation; partikeldispergering; elektriska träd; Fiber- och polymervetenskap; Fibre and Polymer Science;

   Abstract : Nanocomposites of polyethylene and metal oxide nanoparticles have shown to be a feasible approachto the next generation of insulation in high voltage direct current cables. In order to reach an operationvoltage of 1 MV new insulation materials with reduced conductivity and increased breakdown strengthas compared to modern low-density polyethylene (LDPE) is needed. READ MORE

4. 2. Enhanced Active Resonant DC Circuit Breakers for HVDC Grids

   Author : Tim Augustin; Hans-Peter Nee; Marley Becerra; Jürgen Biela; KTH; []
   Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Active damping; Actuator; DC circuit breakers; DC grid; DC power systems; Fast mechanical switch; Fault handling strategy; Gas discharge devices; HVDC; HVDC circuit breakers; Multilevel converters; Multiterminal HVDC; Power transmission; Spark gaps; Thomson-coil actuator; Vacuum interrupter; Voltage Source Converter VSC ; Electrical Engineering; Elektro- och systemteknik;

   Abstract : High-voltage DC (HVDC) grids are considered promising for the electricity grid expansion required to integrate renewable energy sources into the existing infrastructure. DC fault currents increase rapidly and lack a current zero crossing. READ MORE

5. 3. Analysis of VSC-based HVDC systems

   Author : Georgios Stamatiou; Chalmers tekniska högskola; []
   Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; HVDC; MMC; MTDC; Poor damping; Symbolic eigenvalue expressions; Droop control; Passivity Analysis; Net damping; Frequency Domain Analysis; VSC;

   Abstract : The main objective of this thesis is to perform stability and control studies in the area of VSC-HVDC systems. A major part of the investigation focuses on the development of procedures, whose aim is to understand, explain and avoid poorly-damped conditions or instability that may appear due to dc-side resonances, which stem from the interaction of converters and passive elements in such systems. READ MORE

6. 4. Analysis of dc-network stability of VSC-based HVDC grids

   Author : Gustavo Pinares; Chalmers tekniska högskola; []
   Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; power dependent admittance; resonance; HVDC; passivity; Multi-terminal HVDC system; VSC; dc-network stability;

   Abstract : This thesis presents a modelling approach for the investigation of dc-network stability in HVDC grids. It consists on dividing the system under analysis into subsystems such that their individual impact on the stability of the overall system can be studied. READ MORE

7. 5. Operation and control of HVDC links embedded in AC systems

   Author : Jenny Paulinder; Chalmers tekniska högskola; []
   Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; load voltage dependency; system overload; AC DC interaction; HVDC; voltage instability; control of hvdc converters;

   Abstract : .... READ MORE