Search for dissertations about: "High-Voltage dc"

Showing result 6 - 10 of 63 swedish dissertations containing the words High-Voltage dc.

2. 6. High Voltage DC-biased Oil Type Medium Frequency Transformer; A Green Solution for Series DC Wind Park Concept

   Author : Mohammad Kharezy; Chalmers tekniska högskola; []
   Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; High voltage DC; Insulation design; Offshore wind farm; Leakage inductance; High power isolated DC DC converter; Dual active bridge; Medium-frequency power transformer; Parasitic capacitance; HVDC;

   Abstract : The electric energy generated by remote offshore wind parks is transported to the consumers using high voltage submarine cables. On the generation site, such transmissions are realized today by collecting the energy produced by several wind turbines in a bulky and expensive transformer placed on a dedicated platform. READ MORE

4. 7. Active High Voltage Insulation - A New Hybrid Insulation Concept with Dynamic and Active Features

   Author : Jörgen Blennow; Chalmers tekniska högskola; []
   Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; high voltage; surface charge; dielectric coating; charge accumulation; insulation; breakdown strength; covered electrodes; air-gap; dielectric barrier discharges;

   Abstract : In this thesis, the concept of a new environmental-friendly and high-performance high voltage insulation is presented. Basically, it is an electric field steering technique where the dynamic process of charge accumulation, actively and advantageously, re-distributes the electric field within an insulation system. READ MORE

5. 8. Novel Thermoplastic Material Concepts for High Voltage Cable Insulation - Engineering Immiscible Blends for a Sustainable Future

   Author : Yingwei Ouyang; Chalmers tekniska högskola; []
   Keywords : NATURVETENSKAP; NATURAL SCIENCES; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; NATURVETENSKAP; NATURAL SCIENCES; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; polypropylene; polymer blends; thermoplastic; copolymer; high-voltage power cable insulation; polyethylene;

   Abstract : To cope with our growing demand for energy in a sustainable way, efficient long-distance power transmission via high voltage direct current (HVDC) cables is crucial – these cables facilitate the integration of renewable energy into our power networks. For reliable and efficient power transmission, underground and undersea cables require robust insulation materials that possess a high level of mechanical integrity, a low direct-current (DC) electrical conductivity and a high thermal conductivity at the elevated temperatures experienced during cable operation. READ MORE

6. 9. Efficient Modeling of Modular Multilevel Converters for HVDC Transmission Systems

   Author : Noman Ahmed; Hans-Peter Nee; Tim Green; KTH; []
   Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; High-Voltage dc; Modular Multilevel Converter; Voltage-Source Converter; HVDC Grids; Multiterminal DC Systems; Hybrid HVDC Breaker; Modeling; Electrical Engineering; Elektro- och systemteknik;

   Abstract : The drive towards getting more and more electrical energy from renewable sources, requires more efficient electric transmission systems. A stronger grid, with more controllability and higher capacity, that can handle power fluctuations due to a mismatch between generation and load is also needed. READ MORE

7. 10. 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