Search for dissertations about: "High-Voltage dc"

Showing result 21 - 25 of 63 swedish dissertations containing the words High-Voltage dc.

2. 21. On Stability Enhancement in AC/DC Power Systems through Multi-terminal HVDC Controllers

   Author : Omar Kotb; Mehrdad Ghandari; Oriol Gomis Bellmunt; KTH; []
   Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; AC DC power system; hybrid MTDC; multi-terminal HVDC; small signal stability; VSC-MTDC; Electrical Engineering; Elektro- och systemteknik;

   Abstract : Due to the increasing share of renewable energy sources in modern power systems and electricity market deregulation, heavy inter-regional and cross-border power flows are becoming a commonplace in system operation. Moreover, large-scale integration of renewable energy sources is expected to pace up, therefore new solutions have to be developed to integrate these intermittent sources, which are also characterized by being distributed over large geographical areas, such as offshore wind farms. READ MORE

4. 22. Coordinated Frequency Control Using DC Interconnections Between AC Systems : Utilizing Fast Frequency Support through HVDC Links and Evaluating the Newly Uncovered Dynamics in Low-Inertia Power Systems

   Author : Danilo Obradovic; Robert Eriksson; Mehrdad Ghandhari; Damian Flynn; KTH; []
   Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY;

   Abstract : Transmission system operators are increasingly adopting renewable energy sources in response to the escalating need to reduce environmental pollution. However, renewable energy sources, like wind and solar power, connect to the grid through power electronics, offering no inherent inertia. READ MORE

5. 23. A Novel Oil-immersed Medium Frequency Transformer for Offshore HVDC Wind Farms

   Author : Mohammad Kharezy; Per Olof Hedekvist; Yuriu Serdyuk; Thomas Hammarström; Karsten Backhaus; RISE; []
   Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; prototype design methodology; finite element analysis; HVDC insulation design; medium frequency transformer; Wind energy; DC-DC power converters;

   Abstract : In this project, a design of an oil type medium frequency transformer for offshore wind farm applications is proposed. The design is intended for applications when series coupling of the output of the DC/DC converters of the wind turbine on their secondary side is done to achieve a cost-effective high voltage solution for collecting energy from offshore wind parks. READ MORE

6. 24. Characterization of Different Interface Types for HVDC Extruded Cable Applications

   Author : Espen Doedens; Chalmers tekniska högskola; []
   Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; polymer surfaces; cable peelings; HVDC; Roughness; Charge injection; XLPE; Field enhancement factors; Schottky injection; DC breakdown; Voltage decay; interfaces; Fowler-Nordheim injection; extruded cable; Roughness assisted charge injection.; Charge decay;

   Abstract : In extruded HVDC cable systems a variety of interface types can be found, and the interfacial properties depend on the application within the system. Such applications can be joints, terminations or the cable itself and they will all have different material combinations and manufacturing methods. READ MORE

7. 25. PMU-based State Estimation for Hybrid AC and DC Grids

   Author : Wei Li; Luigi Vanfretti; Hao Zhu; KTH; []
   Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Electrical Engineering; Elektro- och systemteknik;

   Abstract : Power system state estimation plays key role in the energy management systems(EMS) of providing the best estimates of the electrical variables in the grid that arefurther used in functions such as contingency analysis, automatic generation control,dispatch, and others. The invention of phasor measurement units (PMUs) takes thepower system operation and control into a new era, where PMUs’ high reportingrate and synchronization characteristics allow the development of new wide-areamonitoring, protection, and control (WAMPAC) application to enhance the grid’sresiliency. READ MORE