Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
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Showing 1 to 20 of 75 for “"HVDC"”.
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HVDC transmission across the Icelandic highlands
A technical feasibility study on an HVDC link connection between the North and the South coast of Iceland across the highlands. A study done with respect to improved stability of the Icelandic transmission system and increased opportunities in load control. Simulations and analysis are carried out …
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Non-pilot Protection of the HVDC Grid
… system, the High-Voltage Direct Current (HVDC) grid. The HVDC grid protection system is required to be (i) adequately fast to prevent damages and/or converter blocking and (ii) reliable to minimize the impacts of faults. This study is mainly focused on the Modular Multilevel Converter …
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Series operation of thyristors in HVDC converters
High voltage direct current. (hvdc) transmission of electrical paver has been made possible with the recent advent of multi-anode mercury arc valves with grading electrodes. However, mercury are valves do suffer from random phenomena such as arcback, which requires special bracing for the converter …
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Improved HVdc dynamic performace via phase locking to virtual Thévenin voltage
… is introduced and evaluated for application in HVdc systems. As compared with the conventional Trans-vector PLL method, it is shown that the enhanced tracking ability of the IC-PLL improves the dynamic performance of the HVdc system. The thesis shows that these benefits accrue in LCC-HVdc …
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One-terminal traveling wave-based protection for HVAC and HVDC transmission lines
… for HVAC (High Voltage Alternating Current) and HVDC (High Voltage Direct Current) systems. It considers the effect of the sampling frequency on the protection, which until now has not been investigated for one-terminal methods. It addresses inaccuracies in wave velocity estimations, which …
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Modeling of voltage source converter based HVDC transmission system in EMTP-RV
… applications include but are not limited to HVDC, Flexible AC Transmission System (FACTS) devices such as STATCOM, SSSC, UPFC and Wind generators and active filters. The VSC based HVDC system is a feasible option for bulk power transmission over long or short distances and the grid …
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Control and operation of MMC-HVDC system for connecting offshore wind farm
… converter (MMC) based high voltage DC (HVDC) system emerges as a more suitable solution than HVAC due to its flexible control and transmission distance not affected by the cable charging current. For HVDC connected wind farms, the offshore wind farm AC networks are established by the …
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IMPACT OF HVDC INVERTER STATION FAULTS ON TURBINE-GENERATOR SHAFT TORSIONAL TORQUES
… system stabilizers, staticvar compensators, HVDC systems, high-speed governor controls and variable speed drive converters. In most of the reported studies concerned with the interaction of HVDC systems with turbine-generator shafts, attention has been focused on the effect of the HVDC …
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Design and performance comparison of Two-level and Multilevel Converters for HVDC Applications
… a two-level and a multilevel converter for HVDC substation. For this study, both topologies were designed with different modulation strategies and compared on the basis of size, power losses and impact on power quality. The model of a basic substation was built in MATLAB, and a 450MVA …
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DC fault protection in HVDC system and the impact on AC frequency response
… over long distance and in many applications, HVDC transmission systems become a more preferable choice compared to conventional HVAC systems. Thus, the reduction of conventional synchronous generators in the system coupled with the increase of DC connections reduces system inertia and weakens …
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Control and operation of offshore wind farms connected with diode rectifier HVDC systems
… wind farms connected with diode rectifier HVDC (DR-HVDC) systems, where a diode rectifier is used offshore and a modular multilevel converter (MMC) is used onshore. Compared to MMC based HVDC systems, the main benefits of DR-HVDC are lower investment, lower space requirement, higher …
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Space charge determination in HVDC power cable and its influence on electric field
… At present, most high voltage direct current (HVDC) installation uses traditional (oil-impregnated paper insulation and oil-filled-types) cables which pose a risk of environmental pollution in case of an accident. <br/><br/>Thus, significant advances and usage of polymeric material, notably …
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Investigation into voltage and angle stability of a hybrid HVAC-HVDC power network
… investigates the power stability problems of HVDC and VSC-HVDC interactions on their hybrid networks with HV AC link, with the intention of bringing out their weaknesses and strengths. The knowledge of this will assist network planners to be informed on ways of improving the efficiency and …
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DYNAMIC ENHANCEMENT OF THE FUTURE SASKPOWER INTERCONNECTED NORTH AND SOUTH SYSTEMS: THE HVDC INTERCONNECTION
… South systems interconnection, namely HVAC and HVDC interconnections (tie-lines). This thesis reports the results of digital time-domain simulation studies that are carried out to investigate the dynamic performance of a proposed 260 km, ± 110 kV, 50 MW Voltage-Sourced Converter HVDC tie-line …
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Design and Optimization of Intelligent PI Controllers (Fuzzy and Neuro-Fuzzy) for HVDC Transmission System
… Voltage Direct Current Transmission Systems (HVDC) by optimizing the key parameters i.e. membership functions (MFs) and fuzzy rule base in the controllers design. In the first part of the thesis, an adaptive Fuzzy PI controller is designed and the effect of various MF shapes, widths and …
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Power flow and rotor angle stability studies of HVAC-HVDC power system interconnections using DigSILENT
The backbone of all industrialised nations is the success of the power sector, which involves an efficient, reliable and secure means of power generation, transmission and distribution. Industrial growth and urbanisation have together endlessly stimulated electrical engineers to ensure that the …
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Control and operation of HVDC connected offshore windfarm with particular emphasis on faults and black start
High voltage direct current (HVDC) technology has been identified as a preferred choice for long-distance offshore wind power transmission. However, compared with conventional onshore networks, the dynamic behaviour and operation of power electronic based offshore network is significantly …
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Modeling, control and stability analysis of VSC-HVDC links embedded in a weak multi-machine AC system.
… performance of high voltage direct current (HVDC) transmission links based on voltage source converter (VSC) technology operating in parallel with the existing longitudinal Australian power system. This thesis presents the principle design methodology to achieve robust controllers for VSCs …
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Comparison of DigSILENT, Matlab PST and PSAT for steady state and stability studies on HVAC-HVDC systems
It is said that the electric power system is the most complex system ever built by mankind. Over the past few decades, many software packages focusing on the study of this complex system have been developed. These software packages range from academic/ research based to industrial/commercial based …
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Development of differential evolution based Power System Stabilizer (PSS) with HVDC in small signal stability analysis using MATLAB
… controller with High Voltage Direct Current (HVDC) to improve the small signal stability (SSS). The Power System Toolbox version 3 MATLAB based software is used as a tool to simulate the results. The results shown that the location of HVDC supplementary in the network contribute to the …
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