Sökning: "island operation"

Visar resultat 1 - 5 av 17 avhandlingar innehållade orden island operation.

1. 1. The Analysis of Thermal Power Stations and their Interaction with the Power System using Simulator Test Methods

   Författare :Jan Andersson; Chalmers tekniska högskola; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; thermal power station; network simulator; frequency control; island operation; turbine model;

   Sammanfattning : This thesis describes a new method of testing power stations with regard to their frequency control behaviour and analyses results obtained using this new method. The test concept is based on that the power station unit to be tested remains synchronized onto its normal strong network, whereas the frequency control behaviour is set up to be that of the conditions if the unit was working on a much smaller network, using a computer based simulator system and feeding simulated control signals to the input of the units frequency control system. LÄS MER

3. 2. Passive Island Detection of Microgrid by Grid Forming Inverter

   Författare :Shoaib Salim Inamdar; Chalmers tekniska högskola; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; microgrid; passive island detection; Grid forming; rotor angle deviation; non-detection zone; inertia; virtual synchronous machine; voltage vector shift.;

   Sammanfattning : The supply reliability of a local grid will be improved if the local grid is managed as a microgrid, with the ability to operate in island mode when the main grid is temporarily unavailable. This thesis focuses on microgrids powered by inverter-based resources (IBRs), one or several of which need to be equipped with grid forming (GFM) capability for establishing and controlling the voltage and frequency of the microgrid during island operation. LÄS MER

4. 3. Projektformen och det industriella arvet: med exempel från sjukvården

   Författare :Anders Edvik; Göteborgs universitet; []
   Nyckelord :SAMHÄLLSVETENSKAP; SOCIAL SCIENCES; SAMHÄLLSVETENSKAP; SOCIAL SCIENCES; project management; project organizing; renewal projects; temporary organizations; health care; public sector; professions; professional bureaucracy; institutions; institutionalization; organizational fields; translation; materialization; interpretation; work life; operation businesses; development; change.;

   Sammanfattning : It is not an exaggeration to say that the idea of organizing work task in a project similar form hasnowadays become an institutionalized understanding in work life in general. Many organizationscombine the permanent organization with temporary such, in purpose to cope with the ongoingchanging environment. LÄS MER

5. 4. Prevalence and Inheritance of Hip Osteoarthritis in Iceland

   Författare :Thorvaldur Ingvarsson; Lund Ortopedi; []
   Nyckelord :MEDICIN OCH HÄLSOVETENSKAP; MEDICAL AND HEALTH SCIENCES; Surgery; gene; inheritance; age standardiation; prevalence; THR; Hip; OA; traumatologi; Kirurgi; ortopedi; traumatology; orthopaedics;

   Sammanfattning : Hereditary factors are suggested to contribute to osteoarthritis (OA), but their relative importance is uncertain. Moreover, the underlying specific variations at the genome level remain unknown. The prevalence of hip OA in Iceland was assessed by examining colon radiographs and was found to be at least 5-fold higher compared to Sweden and Denmark. LÄS MER

7. 5. Modeling and Control of VSC-HVDC Links Connected to Weak AC Systems

   Författare :Lidong Zhang; Hans-Peter Nee; Alan Wood; KTH; []
   Nyckelord :Control; modeling; multivariable feedback control; HVDC; power systems; stability; subsynchronous torsional interaction; voltage-source converter; weak ac systems;

   Sammanfattning : For high-voltage direct-current (HVDC) transmission, the strength of the ac system is important for normal operation. An ac system can be considered as weak either because its impedance is high or its inertia is low. LÄS MER