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Showing result 1 - 5 of 62 swedish dissertations matching the above criteria.

  2. 1. 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

  4. 2. On Techno-economic Assessment of a Multi-terminal VSC-HVDC in AC Transmission Systems

    Author : Feng Wang; Chalmers tekniska högskola; []
    Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Transmission Grid.; Loss minimization; AC DC system; Transmission expansion planning; Multi-terminal VSC-HVDC; Cost minimization; Cost-benefit analysis; Electric power system; Optimal power flow;

    Abstract : The Voltage Source Converter based Multi-Terminal high voltage Direct Current transmission system (VSC-MTDC) is currently considered as an attractive technical option for increased transmission capacity and improved controllability and flexibility of an electric power grid, thanks to its unique performance characteristics, and the possibility of using the extruded XLPE cables. In the planning process of embedding a VSC-MTDC system into an ac transmission grid, one must assess the potential values in terms of improved energy efficiency, i. READ MORE

  5. 3. Design and Optimization Considerations of Medium-Frequency Power Transformers in High-Power DC-DC Applications

    Author : Amin Bahmani; Chalmers tekniska högskola; []
    Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Nanocrystalline-Magnetic Core; High-Power Isolated DC-DC Converter; Solid-State Transformers; Leakage Inductance; Isolation Requirements; Medium-Frequency Power Transformer;

    Abstract : Recently, power electronic converters are considered as one of the enabling technologies that can address many technical challenges in future power grids from the generation phase to the transmission and consequently distribution at different voltage levels. In contrast to the medium-power converters (5 to 100 kW) which have beenessentially investigated by the automotive and traction applications, megawatt and medium-voltage range isolated converters with a several kilohertz isolation stage,also called solid-state transformers (SST), are still in an expansive research phase. READ MORE

  6. 4. Some Control Applications in Electric Power Systems

    Author : Magnus Akke; Industriell elektroteknik och automation; []
    Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; load switching.; power oscillations; differential equation algorithm; transmission line protection; computer relaying; frequency estimation; DC cable; magnetic compass; Automation; robotics; control engineering; Automatiska system; robotteknik; reglerteknik;

    Abstract : This thesis presents some control applications in electric power systems. The work consists of the four parts: interaction between DC cables and ship steering autopilots; frequency estimation; computer relaying; field tests using load switching to damp power oscillations. READ MORE

  7. 5. Organizational Capabilities : A Study of Electrical Power Transmission Equipment Manufacturers, 1878-1990

    Author : Fredrik Tell; Lars Lindkvist; Christian Knudsen; Keith Pavitt; Linköpings universitet; []
    Keywords : SAMHÄLLSVETENSKAP; SOCIAL SCIENCES; Organizational Capabilities; Electrical Manufacturers; Power Transmission; Business History; Technological Change; Knowledge-based Theory of the Firm; ABB; AEG; Alsthom; ASEA; Brown Boveri; CGE; GEC; General Electric; Siemens; Westinghouse; Business Studies;

    Abstract : Organizational capabilities of large industrial firms constitute a pillar in Alfred Chandler's theory of the emergence of managerial capitalism. Science based firms represent one important sector within such an economic context. READ MORE