Dissertations / Theses: 'Offshore wind farm development'

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Cameron, Iain Dickson. "Use of synthetic aperture radar for offshore wind resource assessment and wind farm development in the UK." Thesis, University of Edinburgh, 2008. http://hdl.handle.net/1842/3848.

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The UK has an abundant offshore wind resource with offshore wind farming set to grow rapidly over the coming years. Optimisation of energy production is of the utmost importance and accurate estimates of wind speed distributions are critical for the planning process. Synthetic aperture radar (SAR) data can provide synoptic, wide area wind field estimates at resolutions of a few kilometres and has great potential for wind resource assessment. This thesis addresses the key challenges for the operational implementation of SAR in this context; namely the accuracy of SAR wind retrievals and the ability of SAR to characterise the mean wind speed and wind power density. We consider the main stages of SAR wind retrieval; the retrieval algorithm; sources of a priori information; the optimal configuration of the retrieval system; and the challenges for and accuracy of SAR wind resource estimation. This study was conducted for the eastern Irish Sea in the UK, a region undergoing significant offshore wind energy development. A new wind retrieval algorithm was developed that implements a maximum a posterior probability (MAP) method drawn from Bayesian statistics. MAP was demonstrated to be less sensitive to input errors than the standard direction-based wind speed algorithm (DWSA) and provides a simple retrieval quality check via the error reduction ratio. Retrieval accuracy is strongly influenced by the quality of a priori information. The accuracy of two operationally viable a priori sources, mesoscale numerical weather prediction (NWP) data and WISAR image directions, was evaluated by comparison against in-situ wind observations and WERA coastal data. Results show that NWP wind speeds produce good wind speed and direction estimates with standard deviations of ¬±2 ms-1 and ±16o respectively. WISAR directions were less accurate producing standard deviations ranging from ±20o to ±29o, but were preferable when strong differences between NWP timesteps were observed. The accuracy of SAR wind retrievals was evaluated by comparison against in-situ wind observations. The MAP algorithm was found to provide modest improvements in retrieval accuracy over DWSA. Highest quality retrievals achieved using the CMOD5 forward model, producing wind speeds with a RMSE of 1.83 ms-1. Regarding the ability of SAR to estimate offshore wind resources, dataset density was found to be a controlling parameter. With 103 scenes available mean wind speeds were well characterised by comparison against in-situ observations and Wind Atlas results, while wind power density showed considerable errors. The accuracy of wind speed maps was further improved by accounting for wind direction and fetch effects upon the SAR wind distribution. A key strength of the SAR wind fields is their ability to identify the effect of mesoscale structures upon the surface wind field with atmospheric gravity waves observed in 30% of the images. These structures are shown to introduce wind speed fluctuations of up to ±2 ms-1 at scales of 5 to 10 km and may have significant implications for wind power prediction. These findings show that SAR may provide an important source of wide area wind speed observations as a complement to existing wind resource estimation techniques. SAR may be of particular use in coastal areas where complex wind fields are observed.

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Bergvall, Daniel. "Cost Comparison of Repowering Alternatives for Offshore Wind Farms." Thesis, Uppsala universitet, Institutionen för geovetenskaper, 2019. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-395298.

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The aim of this thesis is to evaluate different repowering alternatives from the viewpoint of increasing power production from existing offshore wind farms (OWF), as some of the first commissioned OWFs are approaching the end of their expected lifetime. The thesis presents a literature review of components and financial aspects that are of importance for repowering of OWFs. In the literature review, risks and uncertainties regarding repowering are also lifted and analysed. The thesis contains a case study on Horns Rev 1 OWF, where three different repowering scenarios are evaluated by technical and financial performance, aiming to compare the cost of repowering alternatives. The design of the case study is based around previous studies of offshore repowering having focused mainly on achieving the lowest possible levelized cost of energy (LCoE) and highest possible capacity factor, often resulting in suggested repowering utilizing smaller wind turbines than the existing ones. In order to evaluate the financial viability of repowering alternatives, the software RETScreen Expert was used to estimate the annual energy production (AEP) after losses and calculate the net present value (NPV) and LCoE for lifetime extension and full repowering utilizing different capacity wind turbines. Input values from the literature as well as real wind resource measurements from the site was utilized to achieve as accurate results as possible. The result of the case study shows that repowering of OWFs have the possibility of providing a very strong business case with all scenarios resulting in a positive NPV as well as lower LCoE than the benchmarked electricity production price. Although the initial investment cost of the different repowering alternatives presented in this thesis still are uncertain to some extent, due to the lack of reliable costs for repowering alternatives, this thesis provides a base for further research regarding the repowering of OWFs.

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Pearce, Bryony. "The ecology of Sabellaria spinulosa reefs." Thesis, University of Plymouth, 2017. http://hdl.handle.net/10026.1/10098.

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Reef habitats built by the tubiculous polychaete Sabellaria spinulosa have been identified as a habitat with significant conservation importance, based on their historic decline across Europe and the assumption that, like many other biogenic reef systems, S. spinulosa reefs enhance biodiversity. Despite the high conservation status of this habitat very little work has been undertaken to explore the role that S. spinulosa reefs play in marine ecosystems, or their sensitivity to anthropogenic disturbance. Observations of the reproductive ecology and population dynamics of the reef building organism indicate that S. spinulosa exhibit life-history traits typically associated with r-strategists, indicating that this species is likely to have the ability to recover quickly following most anthropogenic disturbance events. A series of surveys on S. spinulosa reefs identified at the Thanet Offshore Wind Farm site, where the extent of the reef habitat was found to have increased between the pre-construction and post construction survey despite extensive cable laying and turbine installation, corroborates these findings. Detailed investigations into the macrofauna associated with S. spinulosa reefs in the eastern English Channel revealed that S. spinulosa reefs support macrofaunal communities that are comparable to those associated with adjacent muddy sandy gravel and gravelly muddy sand in terms of species composition, taxonomic breadth and beta-diversity. A consistent enhancement in species richness, abundance and biomass was identified in samples collected from S. spinulosa reefs when compared with adjacent sedimentary deposits, as well as a corresponding reduction in the equitability of species, indicating that some macrofauna are able to exist in higher densities within this habitat. The increase in macrofaunal biomass associated with S. spinulosa reefs was found to influence the diet of demersal fish species, with some species feeding on the reef organism itself while others feed on species found in high densities on the reefs. The high abundance of juvenile flatfish associated with this habitat also suggests that S. spinulosa reefs may provide an important nursery habitat.

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Haugsten, Hansen Thomas. "Offshore Wind Farm Layouts : Performance Comparison for a 540 MW Offshore Wind Farm." Thesis, Norwegian University of Science and Technology, Department of Electrical Power Engineering, 2009. http://urn.kb.se/resolve?urn=urn:nbn:no:ntnu:diva-9990.

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This master thesis has been written at the Department of Electric Power Engineering at the Norwegian University of Science and Technology. The work has been carried out at the Royal Institute of Technology in Stockholm, where the author spent the last year of his studies as an exchange student. In the thesis, six different designs of the electrical grid of a 540 MW offshore wind farm, placed 100km off the Norwegian coast, have been studied and compared. At this distance, AC cable transmission might be difficult because of the reactive power production in the cables. Taking this into consideration, two options for the transmission system to shore have been studied. In addition to the AC cable transmission, voltage source converter based HVDC transmission, in the form of HVDC Light, has been studied, giving a total of 12 models. The main scope of the thesis was to study the load flow situation and power system performance of the different offshore wind farm layouts. Two load flow cases were run for each model; the first studying the model when the active power transmission to shore was maximized, the second studying the model under a contingency situation. The reliability of the six designs was compared by calculating the expected number of cable failures during the life time of the wind farm for each design, and what consequence the disconnection of any cable would have on the power losses. In order to study the effect of the offshore grid design and transmission system design on the offshore power system stability, dynamic simulations have also been executed, and the voltage response and rotor speed response following a fault have been studied. All simulations have been executed in version 31 of the program PSS/E. The wind farm was modeled full scale, consisting of 108 wind turbines rated at 5MW. The wind turbines were modeled as doubly fed induction generators, using the generic wind model that comes with the program. The load flow simulations showed that an AC cable connection to shore gave lower total system losses than a DC connection for all designs. The lowest losses were found at the n-sided ring design in the AC/AC system, and the highest losses were found for the star design in the AC/DC system. These losses were 2.33% and 8.19% of the total installed capacity, respectively. In the dynamic simulations, a three phase short circuit fault, lasting 150ms, was applied at three different places in the system. The simulations showed that except from at the wind turbines that were islanded as a result of a fault, all dynamic responses were stable. The HVDC Light transmission to shore gave the highest voltage drops and the lowest voltage peaks offshore. Also, the maximum speed deviation was found to be larger when using HVDC Light transmission compared to using AC cables, with two exceptions; the radial and star designs when a fault was applied to the transmission system. A comparison of the six different grid designs showed that the results were varying. Based on the results in this thesis it has not been concluded that one of the offshore designs have better dynamic qualities than the other. The simulation results indicated that this is case specific, and more dependent on where in the offshore grid the fault occurs rather than the design of the offshore grid.

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Sinha, Yashwant. "Optimisation of offshore wind farm maintenance." Thesis, Robert Gordon University, 2016. http://hdl.handle.net/10059/1572.

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The installed capacity of European Offshore Wind Turbines (OWT) is likely to rise from the 2014 value of 7GW to 150GW in 2030. However maintenance of OWT is facing unprecedented challenges and cost 35% of lifetime costs. This will be equivalent to £14billion/year by 2030 if current OWT maintenance schemes are not changed. However the complexities around OWT operation require tools and systems to optimise OWT maintenance. The design of optimal OWT maintenance requires failure analysis of over 10,000 components in OWT for which there is little published work relating to performance and failure. In this work, inspection reports of over 400 wind turbine gearboxes (source: Stork Technical Services) and SCADA data (source: Shetland Aerogenerators Ltd) were studied to identify issues with performance and failures in wind turbines. A modified framework of Failure Mode Effects and Criticality Analysis (i.e. FMECA+) was designed to analyse failures according to the unique requirements of OWT maintenance planners. The FMECA+ framework enables analysis and prediction of failures for varied root causes, and determines their consequences over short and long periods of time. A software tool has been developed around FMECA+ framework that enables prediction of component level failures for varied root causes. The tool currently stores over 800 such instances. The need to develop a FMECA+ based Enterprise Resource Planning tool has been identified and preliminary results obtained from its development have been shown. Such a software package will routinely manage OWT data, predict failures in components, manage resources and plan an optimal maintenance. This will solve some big problems that OWT maintenance planners currently face. This will also support the use of SCADA and condition monitoring data in planning OWT maintenance, something which has been difficult to manage for a long time.

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Pillai, Ajit Chitharanjan. "On the optimization of offshore wind farm layouts." Thesis, University of Edinburgh, 2017. http://hdl.handle.net/1842/25470.

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Layout optimization of offshore wind farms seeks to automate the design of the wind farm and the placement of wind turbines such that the proposed wind farm maximizes its potential. The optimization of an offshore wind farm layout therefore seeks to minimize the costs of the wind farm while maximizing the energy extraction while considering the effects of wakes on the resource; the electrical infrastructure required to collect the energy generated; the cost variation across the site; and all technical and consenting constraints that the wind farm developer must adhere to. As wakes, electrical losses, and costs are non-linear, this produces a complex optimization problem. This thesis describes the design, development, validation, and initial application of a new framework for the optimization of offshore wind farm layouts using either a genetic algorithm or a particle swarm optimizer. The developed methodology and analysis tool have been developed such that individual components can either be used to analyze a particular wind farm layout or used in conjunction with the optimization algorithms to design and optimize wind farm layouts. To accomplish this, separate modules have been developed and validated for the design and optimization of the necessary electrical infrastructure, the assessment of the energy production considering energy losses, and the estimation of the project costs. By including site-dependent parameters and project specific constraints, the framework is capable of exploring the influence the wind farm layout has on the levelized cost of energy of the project. Deploying the integrated framework using two common engineering metaheuristic algorithms to hypothetical, existing, and future wind farms highlights the advantages of this holistic layout optimization framework over the industry standard approaches commonly deployed in offshore wind farm design leading to a reduction in LCOE. Application of the tool to a UK Round 3 site recently under development has also highlighted how the use of this tool can aid in the development of future regulations by considering various constraints on the placement of wind turbines within the site and exploring how these impact the levelized cost of energy.

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Al-Mimar, Samer. "Integration of solar and wind power at Lillgrundwind farm. : Wind turbine shadow effect on solar farm atLillgrund wind farm." Thesis, Högskolan i Halmstad, Energivetenskap, 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:hh:diva-28428.

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The supply of energy is a key factor in modern societies. As the old fossil sources for energy are dwindling, conflicts arise between competing nations and regions. Fossil energy sources also contribute to the pollution of the environment and emission of greenhouse gases. With renewable energy sources many of these drawbacks with fossil fuels can be eliminated as the energy will be readily available for all without cost or environmental impact. Combining the renewable energy sources will be very effective, particularly in commercial areas where lake of electricity is high. The cost of combining onshore wind and solar power plant is affordable. Furthermore there is no power failure or load shedding situation at any times. When it is manufactured in a large scale, cost of this integrated natural resources power generation system is affordable. Moreover there is no power failure or load shedding situation at any times. Therefore, it is the most reliable renewable power or electricity resources with less spending and highly effective production. ref [1]. The thesis work would take planning of offshore renewable plant (Lillgrund) with considering the resources of renewable power. The study would take in account combining the Lillgrund wind farm with solar system and take close look into the advantage and disadvantage of combining the renewable resources together and figure out if such station can work in proper way and provide sufficient power production. The study would take in account the effect of each resource on other resource, also calculations would be done. The study site is Lillgrund in south of Sweden. The Lillgrund wind farm is the most important offshore wind power plant installed in Sweden with a total capacity of 110 MW, corresponding to 48 turbines. ref [2].

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Berglund, Arne. "Control System for Reactive Power of an Offshore Wind Farm." Thesis, Uppsala University, Department of Physics and Astronomy, 2010. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-124571.

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Until just a few years ago wind farms where excluded from many of the requirementsthat can be found in grid codes. But as the numbers of wind farms have grown as wellas the sizes of them, the requirements to connect them to the grid have becomemore stringent. In this thesis it has been investigated if it’s possible to design a controlsystem that controls the reactive power from an offshore wind farm, so that the gridcode requirements regarding reactive power are fulfilled. By controlling the reactivepower the dynamic variations in the voltage are decreased. The regulator should alsobe able to help the wind farm to handle the fault conditions that are described in thegrid code.An offshore wind farm outside the coast of Western Europe is now being planned.Data from this wind farm has been used in this thesis. The wind farm has a total of 54wind turbines with more than 300 MW all together. The reactive power is controlledvia the generators and also by disconnecting and connecting four shunt reactors.A model of the wind farm has been built in Simpow, as well as design of the regulator.Simpow is a simulation program developed by ABB that enables simulations of powersystems. Different scenarios have been simulated to see if it is possible to control thewind farm in the desired way. The results show that the wind farm manages to handlefault conditions as described in the grid, and it is also possible to control the reactivepower in a desirable way.

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Västermark, Martin. "Grid Code Compliance – Wind farm HVDC connection." Thesis, Uppsala universitet, Elektricitetslära, 2013. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-204629.

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A rapid development of offshore wind power is planned in GB as a part to fulfil the EU2020 targets. 25 GW wind power capacity has been awarded to developers in nine different offshore zones outside the coast of UK. VSC-HVDC transmission is expected to be a both technical and economical favourable solution for transmitting the power into the main grid. This study investigates if such a transmission solution could comply with the regulatory framework in UK. Vattenfall and Scottish Energy Renewable will be part of this development and have been awarded the rights to develop 7200 MW of wind capacity outside the cost of East Anglia as a part of the offshore expansion plans in UK. The zone is broken down to several projects. The first project is called East Anglia ONE and this project is used as a reference case in this study. The GB Grid Code has been broken down into four areas, voltage and frequency variations; fault ride through requirements, active power control and reactive power control. Load flow calculations and dynamic simulations are designed to investigate compliance of each area. Further, simulations to investigate the interaction between the wind turbines and the offshore converter stations where done. A model representing East Anglia ONE was built in PSS/E and used to investigate grid codes compliance by load flow calculations and dynamic simulations. Data from earlier studies at Vattenfall was used to get a good representation of the wind park. A model representing a HVDC-transmission solution was provided by ABB. The results from load flow calculations and simulations show that a HVDC-solution can comply with the investigated parts of the grid codes. The limiting factor seems to be the capability to inject enough reactive power to the gird at small voltage dips during normal operation. This capability can, however, be enhanced with the right tap-changer settings at the onshore converter transformer.

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Kerkvliet, Hans. "OFFSHORE WIND FARM DECOMMISSIONING: INTRODUCING A MULTI-CRITERIA DECISION AID APPROACH." Thesis, Uppsala universitet, Institutionen för geovetenskaper, 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-256567.

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The objective of this Thesis is to develop a methodological framework to guide the decision maker in selecting a decommissioning method for offshore wind farms which is supported by the majority of relevant stakeholders. Initially, a literature review has been conducted to find out which methods are available to decommission an off-shore wind farm and which criteria can influence the outcome.Two methods have been found in literature, namely partial and total removal of the foundation. Furthermore, twenty one (21) criteria have been found which could influence the results. These criteria can be divided in four categories which are economical, environmental, social and technical.Subsequently, a methodological framework was developed that included four steps. First, the possible decommissioning methods should be identified. Following on that, information should be collected and stakeholders should be selected. Subsequently, criteria should be selected and as last a multi criteria decision aid method should be used. It is expected that this procedure would lead to a decommissioning method which is supported by most of the stakeholders.To validate the methodological framework, a case study in the Netherlands has been selected. For this case study, four (4) stakeholders were identified and eleven (11) criteria were assessed. The outranking multi-criteria decision aid method PROMETHEE II was selected and results were obtained. Analyzing the results, it was possible to conclude that only one stakeholder preferred the total removal method while the other three stakeholders preferred the partial removal method.

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Sajadi, Amirhossein. "Analytical Tools for Transmission Planning Studies for Offshore Wind Farm Integration." Case Western Reserve University School of Graduate Studies / OhioLINK, 2016. http://rave.ohiolink.edu/etdc/view?acc_num=case1459514833.

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Merkai, Christina. "Tidal park within offshore wind parks : An analysis for the potential use of tidal kites within the Aberdeen offshore wind farm." Thesis, KTH, Hållbar utveckling, miljövetenskap och teknik, 2018. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-240594.

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Offshore wind has proved to be one of the most reliable and clean energy sources over the last few years. The industry has experienced a significant growth, with an increase of 101% only in 2017 compared to 2016. This raises the importance of the need for more secure power supply systems, which can be used for controlling the offshore farms during disconnections from the main grid. Nowadays, diesel generators are being used to feed auxiliary services of the offshore wind turbines in situations of emergency. However, as the marine renewable energy industry evolves, tidal energy parks have the potential to replace diesel generators and provide a more sustainable and eco-friendly solution for a long-term auxiliary power system. Moreover, they have the potential to produce extra power, which can be either stored for future use or linked directly to distribution. This report demonstrates a technical, financial and environmental assessment of a potential tidal park within an offshore wind park. Comparison with alternative sources for emergency power supply is also performed. Three alternative locations with high wind speeds and large tidal resource around the UK coast and four different groups of tidal devices are evaluated and compared for the implementation of this solution with the use of ArcGIS maps and other accessible marine data. The Aberdeen wind farm and the tidal kites are selected for further investigation and cost analysis. Seven tidal kites with average power 700 kW and rated power 3.5 MW can provide adequate power to the offshore wind farm for three months without grid connection, whereas they can also provide excess of energy on daily basis when grid disconnection does not occur. The total cost for the project would be approximately 301.6 MSEK. Due to the current renewable energy market, the project is not feasible without high investment risks. However, this study should be evaluated again in the near future when the cost of the tidal device will be further decreased.
Havsbaserad vind har visat sig vara en av de mest tillförlitliga och rena energikällorna under senare år. Inom denna industri har en betydande tillväxt skett, med en ökning med 101% år 2017 jämfört med 2016. Detta relaterar till behovet av säkra elförsörjningssystem, som kan användas för att styra havsbaserade vindraftverksparker under urkoppling från huvudnätet. Numera används dieselgeneratorer som reservkälla till havsvindkraftverk i nödsituationer. Men när den marina förnybara energiindustrin utvecklas, har tidvattenkraftverk potential att ersätta dieselgeneratorer och ge ett mer hållbar och miljövänlig långtidslösning. Dessutom har de potential att producera extra el, som antingen kan lagras för framtida användning eller kopplas direkt till distributionsnätet. Denna rapport erbjuder en teknisk, finansiell och miljömässig bedömning av en potentiell tidvattenkraftverkspark kopplad till en havsvindpark. Jämförelse med alternativa källor för strömförsörjning genomförs också. Tre alternativa platser med hög vindstyrka och stora tidvattenresurser längs Storbritanniens kust och fyra olika grupper av tidvattenanordningar utvärderas och jämförs med hjälp av kartor och andra tillgängliga marina data. Aberdeen vindkraftpark och tidvattendrakar väljs för ytterligare undersökning och kostnadsanalys. Sju tidvattendrakar med genomsnittlig effekt på 700 kW och nominell effekt 3,5 MW kan ge tillräckligt med el till havsvindkraftverk i tre månader utan nätförbindelse, medan de också kan ge överflöd av energi dagligen när strömavbrott inte förekommer. Den totala kostnaden för projektet skulle vara cirka 301,6 MSEK. På grund av läget idag på elmarknaden för förnybar energi, är projektet inte genomförbart utan höga investeringsrisker. Men den här studien bör utvärderas igen inom en snar framtid när kostnaden för tidvattenanordningen har minskat.

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Meisingset, Kristine Kiplesund. "Influence of Offshore Wind Farm on Shore Crab Carcinus maenas Population Dynamics." Thesis, Norges teknisk-naturvitenskapelige universitet, Institutt for matematiske fag, 2013. http://urn.kb.se/resolve?urn=urn:nbn:no:ntnu:diva-21426.

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Many governments have initiated programs of energy production from renewable sources in response to climate changes induced by gases from burning fossil fuels. Use of wind energy is considered a sustainable way of reducing the carbon emission, and offshore wind power generation capacity is expected to grow significantly as the world is trying to make a transition to a lower carbon economy. Though the advantages of renewable energy on a global scale are not in doubt, the effects on the local environment must also be carefully considered. The aim of this study was to investigate the influence of offshore windfarm on shore crab (Carcinus maenas) population dynamics. Data were collected in the Öresund strait in Southern Sweden at Lillgrund offshore windfarm and in to adjacent control areas, Sjollen and Bredgrund. The mark-recapture method was applied to make population size estimation, and the catch per unit effort index was calculated as a measure of abundance. Data on catch per unit effort were also calculated for 8 previous years with data collected from earlier studies in the areas. In addition, size, sex ratio, condition and color were recorded. Due to few recaptures, reliable population size estimations could not be achieved. The population of shore crab within the windfarm was found to be significantly more abundant than those in the control areas in 2012. However, analysis of catch per unit effort in a long term perspective of 10 years, show no effect of the offshore windfarm on shore crab abundance. There was not found any effect of the presence of wind farm on shore crabs regarding size, sex ratio, condition or color.

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Chauhan, Siddharth. "Pile design using wave equation analysis program application in offshore wind farm." Thesis, Massachusetts Institute of Technology, 2008. http://hdl.handle.net/1721.1/43890.

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Thesis (M. Eng.)--Massachusetts Institute of Technology, Dept. of Civil and Environmental Engineering, 2008.
Includes bibliographical references (leaves 54-61).
Pile driving has been of interest to geotechnical engineers for a very long time. Originally, empirical pile driving formulae were used to interpret pile displacements caused by a hammer blow. Smith (1960) proposed a numerical solution for wave propagation in an elastic pile using a finite difference scheme, with lumped mass representation and simple rheological laws for pile-soil interaction. Since then, many significant parameters affecting pile driving have been included in the wave equation analysis. The offshore industry finds much application of pile driving analysis, especially after recent developments in instrumentation and electronic computational tools. Positioning of wind farms offshore and designing a foundation for a floating platform is a challenge to geotechnical engineers. One of the methods to anchor the floating platform is to tether it down to the seabed with help of driven piles. This thesis considers a typical offshore site for designing a driven pile for floating wind farm. The Author has carried out a set of numerical simulations to analyze pile driving at this site using a commercial program (GRLWEAP), and illustrates how this program can be used in pile design.
by Siddharth Chauhan.
M.Eng.

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Sundström, Oskar. "Multi-Criterion Macro-Siting Analysis of Offshore Wind Farm Potential in Sweden." Thesis, KTH, Geoinformatik, 2021. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-301667.

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Sverige har en stor potential för produktion av havsbaserad vindkraft. När teknologin utvecklas och de politiska förutsättningar förändras, kommer konstruktionen av havsbaserad vindkraft i landet troligtvis öka. Den presenterade metodologin går ut på att använda MCDM och AHP metoder i ett GIS för att producera en utvärderingskarta för potentiella platser att producera havsbaserad vindenergi. Målet med den här studien har varit att ta reda på vilken data som krävs och är relevant för att överföra svensk samt internationell standard och regler kring placeringen av havsbaserad vindkraft till ett eller flera lager av GIS data inom Sveriges exklusiva ekonomiska zon. Vidare har de existerande riksintressena för havsbaserad vindkraft utvärderats med hjälp av utvärderingskartan. Denna karta har blivit framtagen med hjälp av flertalet buffertzoner samt exkluderings- och fyra stycken utvärderingskriterier. Slutligen har studiens resultat används för att beräkna en potentiell årlig energiproduktion för offshore vindkraft i Sverige. Studien beaktar några av de sociala, tekniska och miljömässiga begränsningar som finns för havsbaserad vindenergi. Buffertzonerna samt exkluderings- och utvärderingskriterierna har bestämts med hjälp av en inledande litteraturstudie av tidigare forskning på ämnet. Den datan som använts i analysen har inhämtats från flera olika öppna onlineresurser samt från svenska myndigheter. Den efterföljande analysen har genomförts med hjälp av programmet QGIS. För att möjliggöra en kvantifiering av resultaten har utvärderings kartan omklassificerats till fyra olika kategorier: “poor”, “average”, “good” samt “excellent”. Studien visar att det är möjligt att överföra svensk samt internationell standard och regler till ett lager av GIS data. Resultatet visar att att enbart 48% av arean inom de definierade riksintressena för havsbaserad vindkraft bör beaktas vid allokering av havsbaserad vindenergi, enligt de begränsningar som definierats i denna studie. Vidare påvisar resultatet att enbart 19% av arean inom de utpekade riksintressena för vindkraft kan klassificeras som “good” eller “excellent”. Samtidigt påvisar studien att 20.3% av studieområdet bedöms som lämpligt för allokering av havsbaserad vindkraft, av dessa lämpliga områden klassificeras 62.7% som “good” och “excellent”. Den potentiella årliga energiproduktionen uppskattas till 56.1 TWh inom riksintressena för havsbaserad vindkraft samt till 915.3 TWh inom hela studieområdet.

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Walgern, Julia. "Impact of Wind Farm Control Technologies on Wind Turbine Reliability." Thesis, Uppsala universitet, Elektricitetslära, 2019. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-388333.

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Cost efficient operation and maintenance strategies are crucial for reducing cost of wind energy. Since the regime change from feed-in tariffs to an auction-based bidding system for capacity in most European wind projects, levelized cost of energy is challenged constantly. Therefore, new technologies such as new controllers are developed to improve operation and to increase profit. Previous research studies demonstrated the advantage of increased power output of wake redirection control. However, understanding and quantifying the impact of wind farm control technologies on operation and maintenance strategies is inevitable to evaluate the economic feasibility of such new technologies. Thus, an event-based O&M simulation tool has been developed. Besides general modules, such as the wind turbine model, the weather forecasting model and a model for simulating corrective and planned maintenance, the developed tool also takes wake effects into account. This allows considering different power productions for each individual turbine and a failure rate distribution within the wind farm which is based on altering loads on the different components. Both aspects are driven by changes in operation when applying a new controller technology. Exemplarily, the economic feasibility of a closed-loop active wake steering control has been analysed. Main achievements of this study are the possibility to quantify the impact of the active wake steering control on O&M related KPIs. Results show that additional loads caused by applying yaw-misalignment and redirecting wake, lead to an increase in OPEX. However, the achieved energy production gain and thus related additional revenue exceeds additional cost in the case study. Nonetheless, the study reveals that the profitability of the controller is highly dependent on the electricity price which can be acquired during the wind farm’s lifetime.

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Wang, Puyu. "A multi-terminal modular multilevel converter-based HVDC system with an offshore wind farm." Thesis, University of Birmingham, 2016. http://etheses.bham.ac.uk//id/eprint/6442/.

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The increased demand for electrical power and the concern of environmental pollution drive the development of bulk-power transmission over long distance and renewable energy. The use of multi-terminal (MT) modular multilevel converter (MMC) high-voltage direct current (HVDC) technology to integrate power from the offshore wind farm (OWF) is becoming increasingly popular. However, some technological barriers and potential risks may exist in the new technology, which requires comprehensive research and innovative developments. This thesis investigates several important aspects of an offshore integrated MMC multi-terminal HVDC (MTDC) system, including start-up control, control and protection under AC and DC fault conditions. For the start-up control, a hierarchical start-up scheme is proposed for the terminals with active AC networks and a reduced DC voltage start-up scheme is proposed for the terminal with the OWF. Synthesising both schemes forms a comprehensive start-up control scheme for the start-up control of the MTDC system, which can effectively mitigate the voltage spikes and current surges during the start-up process. For control and protection against AC fault conditions, associated control and protection strategies and detailed control and protection sequences are proposed for the faults occurring at the converter AC-side. In addition, a special control and protection strategy is proposed when the faulted-side MMC experiences blocking failure following the fault. For the DC fault management, a fault isolation strategy is proposed and the system recovery scheme is comprehensively investigated after the fault isolation, with delayed-auto-re-configuration (DARC) schemes being proposed. Combining the DARC scheme and the fault isolation strategy, a complete control and protection sequence is proposed. Effectiveness of the proposed schemes is evaluated on the RTDS simulation platform.

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Ho, Terry Chi Young. "AC voltage control of a future large offshore wind farm network connected by HVDC." Thesis, Durham University, 2016. http://etheses.dur.ac.uk/11625/.

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The offshore wind resource around the seas of the UK is a very large renewable energy resource. Future offshore wind farm sites leased by the Crown Estate for Round 3 development will need high power capacity grid connection, but their remote location presents a challenge for the electrical connection to the grid. Long distance AC cable transmission is not practical due to the large cable capacitance which leads to reactive power loss. This thesis considers the voltage source converter and high voltage direct current (VSC-HVDC) technology as the future grid connection for the offshore wind farm network, which is more controllable and has better transmission efficiencies for long distance and high power cable transmission applications. The offshore AC network is weak with very little inertia and has limited rating at the HVDC converter substation. The dynamics in key variables in the offshore wind farm AC network and how they affect certain components in the system were studied. Without proper control, the offshore voltage and the frequency will be sensitive to change. The capacitor of the AC filter at the offshore VSC-HVDC station was found to be vulnerable to over-voltage, therefore a closed loop AC voltage controller was proposed here to maintain a constant capacitor voltage and to prevent tripping or over-voltage damage. The tuning of the control gains were optimised with a pole placement design method and small signal analysis for observing the system eigenvalue damping. The control parameters were then tuned for a fast and well damped controller. The AC voltage controller was evaluated and compared to an open loop system. The controller was able to limit the resonance in the LC filter that can be triggered by large and fast disturbances in the current, voltage and frequency. Current saturation could be implemented within the control structure for device protection from over-currents. Insight on how the wind turbine fully rated frequency converters and controllers may interact with the VSC-HVDC converter station is also discussed.

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19

Wood, Thomas Benedict. "Interaction of DC-DC converters and submarine power cables in offshore wind farm DC networks." Thesis, University of Edinburgh, 2014. http://hdl.handle.net/1842/11767.

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Offshore wind power is attracting increasing levels of research and investment. The use of HVDC transmission and the development of DC grids are topics with similar high levels of interest that go hand in hand with the development of large scale, far from shore wind farms. Despite increased capital cost of some components, DC power transmission can have significant advantages over AC transmission, in particular in the offshore environment. These advantages are well established for large scale, long distance point to point transmission. This thesis assesses the suitability of a multi-terminal DC power collection network, with short cables and relatively small amounts of power, addresses a number of the technical challenges in realising such a network and shows methods for overall system cost reduction. Technical and modelling challenges result from the interaction between power electronic DC-DC converters and the cables in a DC transmission network. In particular, the propagation of the ripple current in bipole DC transmission cables constructed with a metallic sheath and armour is examined in detail. The finite element method is used to predict the response of the cable to the ripple current produced by the converters. These results are used along with wave propagation theory to demonstrate that cable design plays a crucial role in the behaviour of the DC system. The frequency dependent cable models are then integrated with time domain DC-DC converter models. The work in the thesis is, broadly, in two parts. First, it is demonstrated that care and accuracy are required in modelling the cables in the DC transmission system and appropriate models are implemented and validated. Second, these models are combined with DC-DC converter models and used to demonstrate the practicality of the DC grid, make design recommendations and assess its suitability when compared with alternative approaches (e.g. AC collection and/or transmission).

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20

Liu, Zhenyu. "COMPARISON OF THE WIND POWER PRODUCTION MODELS IN THE BALTIC SEA, A CASE STUDY IN THE LILLGRUND OFFSHORE WIND FARM." Thesis, Uppsala universitet, Institutionen för geovetenskaper, 2021. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-448174.

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Wind energy, which is no emission of greenhouse gases, is attracting increasing attention world widely. Compared to onshore wind farms, offshore wind farms can yield greater power production since the wind speeds over the sea are higher and steadier than those over the land. An increasing number of offshore wind farms are being planned and deployed all over the global near-sea areas. Thus, accurate evaluation of wind power production is essential for offshore wind farm development. This study compares two popular models, the minimalistic prediction (MP) model and the linear WAsP model, in the modeling power production of the Lillgrund offshore wind farm in the Baltic Sea. The wind condition data from New European Wind Atlas (NEWA) is used to analyze the wind resources and as input data of the models to calculate wind power production. The calculated results are compared in different years and wind direction sections. The sensitivity of the calculated power production to different influencing factors, including the size of the wind farm and hub heights, are examined. The results show that the WAsP model generally yields higher energy production than the Minimalistic Prediction (MP) model. The requirement for wind condition data and wind farm layout parameters in those two models is different. Compared to the WAsP model, the MP model does not require detailed wind farm layout parameters and wind direction data, which leads to different power production results. From the results of sensitivity experiments, both the size of the wind farm and hub heights have an impact on power production. When the wind farm size increases by 5 times the original size, the wind power production increases by around 50 %. However, when the distances between wind turbines are large, the wake effect would disappear gradually. Therefore, the growth rate decreases with the increase in the size of the wind farm. The wind speed is higher with the increase in hub height. However, due to the smaller turbulence flux, the increase in wind power production with higher hub height is not obvious. When the hub height increased by 2.6 times, the wind speed just increased by around 13 %. It is not hard to conclude that designing a wind farm is a process full of trade-offs. Balancing the rich wind resources and the financial benefits from offshore wind farms are equally essential. Our study can contribute to the application of the models and the designing of offshore wind farm layouts in the Baltic Sea.

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Negash, Teklebrhan. "Wind resource assessment for posibel wind farm development in Dekemhare and Assab, Eritrea." Thesis, Högskolan i Halmstad, Akademin för ekonomi, teknik och naturvetenskap, 2018. http://urn.kb.se/resolve?urn=urn:nbn:se:hh:diva-36835.

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Recently wind resource assessment studies have become an important research tool to identify the possible wind farm locations. In this thesis work technical analysis was carried out to determine the wind resource potential of two candidate sites in Eritrea with help of suitable software tools. The first site is located along the Red Sea cost which is well known for its wind resource potential, whereas the second site is located in the central highlands of Eritrea with significant wind resource potential. Detailed wind resource assessment, for one year hourly weather data including wind speed and wind direction, was performed for the two candidate sites using MS Excel and MATLAB. The measured wind data at Assab wind site showed that the mean wind speed and power density was 7.54 m/s and 402.57 W/m2 , whereas the mean wind speed and mean power density from Weibull distribution was 7.51 m/s and 423.71 W/m2 respectively at 80m height. Similarly, the measured mean wind speed and mean power density at Dekemahre wind site was obtained to be 5.498 m/s and 141.45 W/m2, whereas the mean wind speed and mean power density from Weibull distribution was 5.4859m/s and 141.057W/m2 respectively. Based on the analysis results Assab wind site classified as wind class-III and Dekemhare as wind class-I. Wind farm modeling and Annual Energy Production (AEP) estimation was performed for E-82 & E-53 model turbines from Enercon Company with the help of MATLAB and Windpro software. The analysis revealed that Assab wind farm was an ideal site for wind energy production with capacity factor (CF) 53.4% and 55% for E-82 and E-53 turbines respectively. The gross and net AEP for turbine E-82 at Assab wind farm was 469.5 GWh and 446.025 GWh respectively with 95% park efficiency. Similarly, the analysis showed that the CF in Dekemhare site was very low with typical value 14.2% and 15.26% for E-82 and E-53 turbines respectively. The gross and net AEP of that site for model turbine E-53 was 53.5 GWh and 50.825 GWh respectively with 5% wake loss. Finally, a simplified economic analysis was carried out to determine the economic feasibility of possible wind power projects in both sites by assuming investment cost 1600 €/kW for E-82 turbine and 2000 €/kW for E-53 turbine. The total wind farm investment cost was found to be 215.85 and 107.93 Million Euro for E-82 and E-53 model turbines respectively. The levelized cost of energy at Assab and Dekemhare wind farm for E-82 model turbine was 0.0307 €/kWh and 0.5526 €/kWh respectively. The analysis result show that the levelized cost of energy in Dekemhare wind fasrm was much higher than that of Assab wind farm.

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Takuba, Raymond Chengetai. "The effect of wind turbine transportation on wind farm development in South Africa." Master's thesis, University of Cape Town, 2014. http://hdl.handle.net/11427/13261.

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Includes bibliographical references.
This thesis investigates the transportation of wind turbines in an emerging wind energy market with a focus on South Africa. The research goal is to understand how the transport and the wind energy sectors interact; as well as how turbine transportation can unfold as a barrier to wind farm development in South Africa. Turbine transportation was found to be a key part of the wind farm development process which has been hampered in South Africa by poor planning, the design of the renewable energy procurement program and low cooperation amongst industry participants. Barriers to wind farm development include a shortage of logistics equipment such as cranes and trailers, a shortage of skilled drivers and crane operators and several embedded bottlenecks in the abnormal load transportation process. These factors combined have resulted in a cost premium of 5 - 10% for the turbine transportation process in South Africa as compared to the cost in larger established wind energy markets. The study additionally finds that the wind energy industry could benefit from better coordination of transport projects through industry bodies such as SAWEA, as the transport system is unlikely to be altered in order to accommodate the needs of the wind energy industry.

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Masoomi, Mohammad. "Model Development and Load Analysis of an Offshore Wind Turbine." University of Toledo / OhioLINK, 2014. http://rave.ohiolink.edu/etdc/view?acc_num=toledo1404552688.

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24

Unida, Roberto. "An investigation on the offshore wind energy potential in Italy and its deployment with floating turbines." Master's thesis, Alma Mater Studiorum - Università di Bologna, 2020.

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The thesis aim is to offer a general assessment of potential of offshore wind deployment in Italy. More specifically, it aids with the identification of the most promising locations and estimates the levelized cost of energy of the areas found suitable. Furthermore, the thesis develops a simple technical feasibility study at one of these sites, which specifically focuses on the design of the wind turbines foundations, considering and comparing different geotechnical solutions. It is been found that, in Italy, the offshore area suitable for the installation of wind farms is approximately 110,000 km2, with an estimated theoretical annual energy production of 188.25 TWh, more than half of the Italian electricity need. Locations identified as promising are the Adriatic Sea, and the Ionian Sea of the Apulia region and the South-West part of Sicily. For these areas the LCOE analysis has yielded values ranging between 90 $/kWh to 130 $/kWh, in line with European average. The case of study indicated that anchors’ cost strongly depends on local met-ocean conditions, as it is found by comparing the results obtained for the Italian case study with Hywind Scotland pilot floating wind farm, used as benchmark. Comparison between two different anchor solutions has also shown that the foundation choice has also a significant impact on the overall cost for a plant set-up.

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Vedin, Felix. "System analysis of a fossil free steel manufacturing plant powered by an offshore wind power farm." Thesis, KTH, Kraft- och värmeteknologi, 2021. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-299938.

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Major changes are taking place in the Sweden’s electricity system and steel industry. Through political agreements, the current government has set national goals of 100% renewable electricity generation and a net zero GHG emissions industry by 2040. This will be achieved by increasing renewable power generation, mainly wind power. In the steel industry, the steel manufacturing groups are beginning to transition to an electricity-based steel manufacturing processes to reduce their GHG emissions. The Swedish steel manufacturing group SSAB and the mining group LKAB, together with Vattenfall, are developing an alternative steel production process free from fossil-based sources. It is called HYBRIT, an alternative technique to reduce iron ore with hydrogen gas, instead of coal which is used today. By producing hydrogen with electrolysis, applying hydrogen reduction technology, and replacing coal powered blast furnaces with electrified arc furnaces for melting the steel, it is possible to create a green and environmentally friendly steel industry. This technique was simulated in a computer model where electricity flows and system component capacity requirements were calculated. The simulation was made of an existing steel manufacturing plant in Oxelösund. A hypothetical case was made where the plant has a fully incorporated HYBRIT steel production chain. Its main power source was a nearby offshore wind power farm which is a planned project by Svea Vind Offshore. Previous studies have simulated HYBRIT steel manufacturing in computer models. However, no similar studies have been made on how these systems operate with variable availability of renewable power. From two studied wind power farm layouts, the results found a relationship between the needed electrolysis capacity as a function of the concentration recycled steel used in the process and the yearly steel production demand. Using the stated goal of SSAB where they use 50% recycled steel as a reference, it was calculated that 286 – 309 MW electrolysis unitsis needed for a yearly steel production of 1.6 million tonnes.
Det sker stora förändringar inom Sveriges elkraftsystem och stålindustri. Den nuvarande regeringen har genom politiska överenskommelser satt nationella mål på 100% förnybar elproduktion, och nollnetto GHG utsläpp inom industrin, tills 2040. Det ska nås genom att öka förnyelsebar elproduktion, huvudsakligen vindkraft. I stålindustrin har ståltillverkningskoncernerna börjat övergå till en elektrifierad ståltillverkningsprocess för att minska utsläppen. Den svenska stålkoncernen SSAB, och gruvdriftskoncernen LKAB, tillsammans med Vattenfall utvecklar en alternativ ståltillverkningsprocess som är fri från fossila källor. Det heter HYBRIT, och är en alternativ metod för att reducera järnmalm med vätgas, i stället för kol som används idag. Genom att producera vätgas med elektrolys, installera vätgasreduktionsteknik, och ersätta de koldrivna masugnarna med eldrivna ljusbågsugnar för att smälta stålet, är det möjligt att skapa en grön och miljövänlig stålindustri. Denna teknik simulerades i en datormodell där elektricitetsflöden och begränsningarna på kapaciteten på systemkomponenterna beräknades. Simuleringen gjordes på ett existerande stålverk i Oxelösund. Ett hypotetiskt fall sattes upp där verket har inkorporerat hela HYBRIT stålproduktionskedjan. Den huvudsakliga kraftkällan var en närliggande havsbaserad vindkraftspark som är ett föreslagit projekt av Svea Vind Offshore. Tidigare studier har simulerat ståltillverkning med HYBRIT teknik i datamodeller. Men, det finns ingen liknade studie som har studerat hur dessa system fungerar med en varierande tillgänglighet på förnyelsebar effekt. Utifrån två studerade vindkraftsparkdesigner blev resultatet en relation mellan den behövda elektrolyskapaciteten som en funktion av andelen återvunnet stål i processen samt det årliga stålproduktionsbehovet. Genom att använda SSAB:s framtida mål där de använder 50% återvunnet stål som referens, beräknades det att 286 – 309 MW elektrolysenheter behövs för en årlig produktion på 1.6 millioner ton stål.

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Yu, Xi. "Modelling offshore wind farm operation and maintenance with view to estimating the benefits of condition monitoring." Thesis, University of Strathclyde, 2016. http://digitool.lib.strath.ac.uk:80/R/?func=dbin-jump-full&object_id=27387.

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Offshore wind energy is progressing rapidly and playing an increasingly important role in electricity generation. Since the Kyoto Protocol in February 2005, Europe has been substantially increasing its installed wind capacity. Compared to onshore wind, offshore wind allows the installation of larger turbines, more extensive sites, and encounters higher wind speed with lower turbulence. On the other hand, harsh marine conditions and the limited access to the turbines are expected to increase the cost of operation and maintenance (O&M costs presently make up approximately 20-25% of the levelised total lifetime cost of a wind turbine). Efficient condition monitoring has the potential to reduce O&M costs. In the analysis of the cost effectiveness of condition monitoring, cost and operational data are crucial. Regrettably, wind farm operational data are generally kept confidential by manufacturers and wind farm operators, especially for the offshore ones. To facilitate progress, this thesis has investigated accessible SCADA and failure data from a large onshore wind farm and created a series of indirect analysis methods to overcome the data shortage including an onshore/offshore failure rate translator and a series of methods to distinguish yawing errors from wind turbine nacelle direction sensor errors. Wind turbine component reliability has been investigated by using this innovative component failure rate translation from onshore to offshore, and applies the translation technique to Failure Mode and Effect Analysis for offshore wind. An existing O&M cost model has been further developed and then compared to other available cost models. It is demonstrated that the improvements made to the model (including the data translation approach) have improved the applicability and reliability of the model. The extended cost model (called StraPCost+) has been used to establish a relationship between the effectiveness of reactive and condition-based maintenance strategies. The benchmarked cost model has then been applied to assess the O&M cost effectiveness for three offshore wind farms at different operational phases. Apart from the innovative methodologies developed, this thesis also provides detailed background and understanding of the state of the art for offshore wind technology, condition monitoring technology. The methodology of cost model developed in this thesis is presented in detail and compared with other cost models in both commercial and research domains.

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Martin, Heather Rae. "Development of a Scale Model Wind Turbine for Testing of Offshore Floating Wind Turbine Systems." Fogler Library, University of Maine, 2011. http://www.library.umaine.edu/theses/pdf/MartinH2011.pdf.

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GHAZALI, Najoua. "WIND DEVELOPMENT IN WALLONIA." Thesis, KTH, Energiteknik, 2011. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-35219.

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Nordex, a wind-turbine manufacturer and developer, has just launched the development activity over Belgium’s French-speaking Region – the Walloon Region – with the current political context favorable to wind energy deployment. Since the Walloon market is unknown, the master thesis aims to identify the appropriate approach to use for optimal wind farm development and the critical issues that may impinge on it. The scope of the master thesis is thus to find two to three sites well suited for wind farm implementation in the province of Luxembourg and to develop these sites. An exhaustive study of the wind farm potential of the province of Luxembourg has been led, based on geographic data analysis with the GIS ArcGIS®, feasibility studies conducting, meetings with districts’ administration as well as visits onsite. In addition, a thorough comparative analysis of the Belgian specification for grid connection has been performed to identify any requirement that is not included in the French and German grid codes, which are the benchmarks of the development activity in Nordex France. Many obstacles have been encountered in wind farm development, chiefly a strong existing competition in the wind energy sector and a limited grid capacity. In addition time can be a friend but it can also sometimes be a foe at some stages that rely on public administration. Consequently from the 40 identified sites with ArcGIS®, only three have succeeded. Regarding the Belgian requirements for grid connection, all can be met thanks to an existing German specification data sheet. Eventually the Walloon policy towards wind energy development is expected to evolve so as to foster wind farm deployment in Wallonia and to reach the objectives set for 2020 (2200 MW of installed wind capacity while in January 2011 only 440 MW were in operation). Consequently to that, Nordex’ approach may have to adapt to the new regulations.

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Kurt, Melih [Verfasser]. "Development of an Offshore Specific Wind Power Forecasting System / Melih Kurt." Kassel : Kassel University Press, 2017. http://d-nb.info/1143153545/34.

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30

Zhang, Mimi Q. "Feasibility analysis of coordinated offshore wind project development in the U.S." Thesis, Massachusetts Institute of Technology, 2008. http://hdl.handle.net/1721.1/45762.

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Thesis (M.C.P.)--Massachusetts Institute of Technology, Dept. of Urban Studies and Planning, 2008.
Includes bibliographical references (p. 53-62).
Wind energy is one of the cleanest and most available resources in the world, and advancements in wind technology are making it more cost effective. Though wind power is rapidly developing in many regions, its variable nature creates obstacles in integrating significant amounts of wind power to the electric grid. One potential solution for reducing the fluctuating nature of wind power is to site wind projects in regions of complementing wind regimes to reduce variability. This thesis explores the feasibility of creating a coordinated network of offshore wind projects through examining its technological requirements, economic viability, and the policy and planning issues of building such a network in the U.S. Wind speed data for sites along the east coast of the U.S. are used to analyze the nature of offshore wind patterns and the benefits of interconnecting multiple wind projects. The main questions are: 1) Is an offshore wind network technologically feasible? 2) What are the costs and benefits of creating an offshore network with transmission lines? 3) What are potential ways to plan, permit, and develop such a network? An overview of research on existing turbine technology, turbine foundation technology, and transmission technology show that it is technically possible to build a network of offshore wind projects. An analysis of the costs and benefits of physical interconnection show that the cost savings from reduced variability pale in comparison to interconnection costs. It is more cost effective to coordinate the siting of all projects within the network, by connect the projects directly to the onshore grid as opposed to creating a separate, offshore grid for wind projects. The current planning process for offshore wind development permits projects on a site-by-site basis, so developing an entire network of sites with the goal of reducing variability would require an extensive stakeholder process where all relevant parties agree on a set of sites. A coordinated network could also be developed over time by incorporating variability as a priority in the permitting process.
by Mimi Q. Zhang.
M.C.P.

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Renaudin, Fabien. "Integration and Stability of a Large Offshore Wind Farm with HVDC Transmission in the Norwegian Power System." Thesis, Norwegian University of Science and Technology, Department of Electrical Power Engineering, 2009. http://urn.kb.se/resolve?urn=urn:nbn:no:ntnu:diva-9820.

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In the last decades, due to the environmental concerns and the increase of energy demand, wind power has strongly penetrated the field of electricity generation. Today, because of the lack of onshore sites and visual and noise nuisances, the development of wind farms turns more and more to offshore and Norway has a great potential of offshore wind power. This thesis investigates the impact of the integration of an offshore 1000MW wind farm on the Norwegian power system. Two different transmissions are used, one HVAC transmission system and one HVDC transmission system. They are installed in four different configurations which represent the possible cases of wind farm integration regarding the distance from the shore. Two different connection points have been chosen regarding the load flow simulations. The first one is situated in the region of Bergen in the West Norway and the other one is situated between Kristiansand and Stavanger in the south Norway. In order to investigate the power stability and the behaviour of the system, simulations are performed under both steady-state and dynamic conditions by using PSSTME. Disturbances are applied in different locations on the system both near the connection point and on the offshore wind farm. The results show that the power system with large offshore wind power remains stable after the different faults. The requirements of the Norwegian Transmission System Operator, Statnett, are respected after the integration of a large offshore wind farm in the Norwegian power system.

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Martin, Rebecca. "Sensitivity analysis of offshore wind farm availability and operations & maintenance costs subject to uncertain input factors." Thesis, University of Strathclyde, 2016. http://oleg.lib.strath.ac.uk:80/R/?func=dbin-jump-full&object_id=27078.

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The deployment of offshore wind farms (OWFs) has increased in response to the threat of diminishing fossil fuel resources, climate change and the need for security of supply. The cost of offshore wind generation has not reached parity with established forms of electricity production. Operators need to simultaneously decrease the total project costs and increase energy yield to achieve a levelised cost of energy of £100/MWh. However, aspects of the Operations and Maintenance (O&M) remain uncertain, either through stochastic processes or through inexperience in the field. One way to handle uncertainty is to define how much the variance in these aspects affect the cost and availability. The thesis in hand introduces an O&M model and seeks to quantify the effects of uncertain inputs using complex sensitivity analysis methods. The sensitivity analysis is applied to an O&M computer simulation model for offshore wind that was developed prior to this project. Case study OWFs are identified to assess if the important factors are different when projects are comprised of a large number of wind turbine generators (WTGs) and are further offshore from the O&M hub port. The set of cases for the global sensitivity analysis comprises of three projects, to provide information applicable to the industry and demonstrate pertinence of sensitivity analysis on a case by case basis. A screening analysis, using the Morris method, is conducted to identify the most important factors on project cost and availability. This resulted in a list of twenty factors, relating to failure rates; duration of operations and information relating to vessels costs. An in-depth uncertainty analysis is conducted with the important factors to establish their distributions where possible. A global, variance-based sensitivity analysis, using the Sobol’ method, is performed to quantify the effect on the variance of the two outputs. No single factor dominated the effect on O&M cost and availability for all cases. For each case, one to five factors contributed most to output variances. As an example, for a case of 30 WTGs located 20km offshore from the O&M hub port, the output variances are mainly a result of the change of number of crew transfer vessels and heavy lift vessel mobilisation time for nacelle component replacement. For an OWF with more WTGs, further from shore; the availability variance is dominated by more routine repair operations. Moreover, costs are largely dominated by WTG reliability. This work has confirmed that O&M costs are affected by the cost of deploying heavy-lift vessels even though only a small proportion of repairs require them. Significant factors are inconsistent across all the scenarios, supporting the conclusion that sensitivity analysis of each case is a necessary part of O&M costs and availability simulation. Using the most up-to-date information on current O&M practices, the analysis provides an indication of where to focus efforts for O&M cost reduction and improved availability.

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Zhang, Haibo. "Analysis and performance enhancement of a series parallel offshore wind farm topology integrated into a HVDC grid." Thesis, Lille 1, 2017. http://www.theses.fr/2017LIL10156/document.

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L'exploitation de l'énergie éolienne loin des côtes, bien qu'abondante, dépend du transport de puissance en Courant Continu Haute Tension (HVDC) qui nécessite une sous-station placée sur une plateforme dédiée. Cette plate-forme offshore étant volumineuse, son cout d'installation est élevé et sa mise en œuvre est compliquée. Cette thèse s'intéresse à une topologie de ferme éolienne offshore DC qui transporte son énergie vers l'onshore sans utiliser de sous-station offshore. Ce type de Ferme Eolienne est appelé Ferme Eolienne Série Parallèle (SPWF). Il est composé de plusieurs grappes d'éoliennes interconnectées en série, de sorte que cette interconnexion engendre directement un niveau de tension adapté à la tension du réseau HVDC. Cependant, la connexion en série implique que la tension de chacune d'entre elle n'est plus constante. Un déséquilibré de production d'énergie conduit à des variations des tensions en sortie des éoliennes. Ces variations de tension peuvent engendrer des surtensions aux bornes d'une éolienne dans la grappe et l’endommagé. Une stratégie permettant de limiter la surtension d'éolienne est proposée et développée. Cette stratégie est d'abord validée dans un contexte de connexion point à point avec la prise en compte de la transmission HVDC basée sur des câbles DC et un Convertisseur Modulaire Multiniveaux (MMC) permettant de la connecté au réseau onshore. Dans un second temps, la ferme SPWF est intégrée dans des systèmes DC multi-terminaux (MTDC). Les résultats de simulation démontrent la faisabilité de la stratégie et montrent qu'aucune réduction de puissance n'est alors nécessaire pour limiter les tensions en sortie des éoliennes
The massive exploitation of far offshore wind energy relies heavily on the High Voltage Direct Current (HVDC) transmission system, in which dedicated offshore substations for converting power from AC into DC are necessary. However, the bulky offshore platform is costly and its installation is complicated. This thesis aims to contribute to the study of a pure DC offshore wind farm topology which exports its energy to onshore without using an offshore centralized power conversion substation. The examined wind farm topology is called Series Parallel Wind Farm (SPWF), which comprises several clusters of wind turbines connected in series, so that the output converters of the wind turbines step up the voltage to a higher level for direct power transmission. However, due to this distinctive feature, unbalanced power production of wind turbines leads to output voltage variation of wind turbines, which is harmful to the wind turbines. The work carried out in this thesis begins with the identification of the basic elements to constitute the SPWF. Afterwards, the operation of the SPWF is explained and its overvoltage characteristic is described and emphasized. An overvoltage limitation control strategy is developed, which requires an active participation of the onshore converter. Hence, the onshore Multilevel Modular Converter (MMC) as well as the HVDC cables models are examined. The control strategy is applied to both Point-to-Point (P2P) HVDC transmission system and Multi-Terminal DC (MTDC) systems. The results validate the feasibility of the proposed strategy, and demonstrate its advantage of no power curtailment requirement to limit the wind turbines output voltage

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Tseng, Kuo-Chun, and 曾國鈞. "The Navigation Risk Assessment of Offshore Wind Farm Development." Thesis, 2014. http://ndltd.ncl.edu.tw/handle/21845417908117165877.

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碩士
國立臺灣海洋大學
通訊與導航工程學系
102
This thesis focuses on the navigation risk assessment of offshore wind farm's development, estimating the collision probability of ships sailing near by the offshore wind farms' development area, and assessing the impact of offshore wind farms to the navigation safety. This research also discusses the possibility of reorganizing the ships' traffic near by the wind farm with routeing measures, and the effect of ship-to-ship and ship-to-wind farm collision probabilities after routing. Routing the traffic not only concentrates the sailing vessels but also allows more space for the development of offshore wind farms. This study takes Taiwan’s demonstration wind farm as an example to estimate the navigation risk assessment. The research assesses vessel-to-wind farm’s collision probability and finds the appropriate route center of the vessel traffic by using distributions and parameters extracted or discovered from huge AIS (Automatic Identification System) data, then compares navigation risks for cases with and without routing.

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Huang, Guan-Jie, and 黃冠傑. "Development of a multipurpose auxiliary vessel for offshore wind farm installation." Thesis, 2019. http://ndltd.ncl.edu.tw/handle/t2z3au.

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碩士
國立臺灣海洋大學
系統工程暨造船學系
107
This study is to propose a method to enhance operation capability of a Jack up type offshore wind-farm installation unit in high sea. This method is to place a moored vessel ahead of a wind-farm installation unit to induce wave shielding effect, which helps to reduce motion response of the unit and enhance its operation capability of wind-farm installation. ANSYS AQWA is utilized to analyze hydrodynamic interaction between the vessel and the wind-farm installation unit to examine the wave shielding effect. Pitch and heave motion RAOs (Response Amplitude Operator) of the installation unit with or without the vessel placing ahead are compared to evaluate the wave shielding effect for different wave incident angles and wave periods. In addition, a range of variation of breadth and draft of the vessel are included in this study for optimization of principal dimensions based on the induced wave shielding effect. The vessel is also proposed multipurpose to accommodate workers on board as a hotel at sea. This design consideration enables workers to live closely to the installation unit, which can be very beneficial on cost saving to a wind-farm project by supporting 24 hours shifting working schedule, reducing hotel necessity on shore, and omitting routine commuting between shore and the installation. Based on the wave data in the wind-farm zone offshore of the Taichung Harbor, the most common waves in that zone are waves of period 6~7 second. From the results of the study, it is observed that the vessel with draft of 12.5 meter and greater is more effective to induce wave shielding effect, which helps to reduce the pitch and heave motion RAOs of the installation unit to 1/3 or less in the waves of period 6~7 second. The deeper the draft of the vessel, the more wave shielding effect, and the more motion reduction to the installation unit. It is also observed that breadth variation of the vessel has small effect on its motion response at wave angle of 0~30 and period of 6~7 second. However, if the draft of the vessel increased, its motion response is reduced at wave angle of 0~30 and period of 6~7 seconds. Hence, the multipurpose vessel with deeper draft and narrower breadth can be designed to accommodate workers living comfortably on board and provide needed wave shielding effect to the installation unit in the wind-farm zone offshore of Taichung Harbor.

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Chiuan-LinChen and 陳湶霖. "Strategy Analysis of Wind Farm Position and Block Development in Taiwan's Offshore Wind Power Potential Sites." Thesis, 2018. http://ndltd.ncl.edu.tw/handle/4m954w.

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TSOU, MIN-SHAN, and 鄒旻珊. "The Development of Visualization Ship Dynamic Monitoring System in the Offshore Wind Farm Area." Thesis, 2019. http://ndltd.ncl.edu.tw/handle/s2b69p.

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碩士
國立高雄科技大學
電訊工程系
107
The world is facing the problem of insufficient energy, and countries are vigorously promoting the use of renewable energy, Taiwan Executive Yuan has approved a policy named 「Four-Year Plan of Promotion for Wind Farm Area」in June 2017.When developing offshore wind farm area, re-planning the navigation channel of the ship is needed due to the safety of the offshore wind farm area. Whether the ship is actually sailing within the planned navigation channel is a major problem that cannot be ignored. Therefore, in order to avoid the ship not follow regulation sailing in the offshore wind farm area. This paper obtains information about current ship dynamic information through Automatic Identification System(AIS) provided by the Institute of Harbor and Marine Technology Center, and integrate the boundary information of the offshore wind farm area announced by Bureau of Energy as the key point of system development. The system uses two kind of servers for development, the database server(back-end) use C# and Structured Query Language(SQL) to design Application Programming Interface(API) as channel for data extraction and consolidation another website server(front-end) use Hyper Text Markup Language(HTML) and JavaScript Cascading Style Sheets(CSS) to design system display interface. In the paper, the system uses point-in-polygon operations ray casting algorithm to instantly monitor and judge whether the ship is located in offshore wind farm area, furthermore, this paper present the statistics of the number of ships entering the offshore wind farm area in month by interactive data visualization, according to the statistical analysis results, the type and quantity of ships sailing in the wind power area can be clearly understood, these results can be provided to relevant units to study the impact of the establishment and management of navigational prohibited areas in navigation channels and offshore wind farm areas after the establishment of offshore wind farm area.

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Liu, Wen-Tsan, and 劉文燦. "A Study of Standard Operating Procedures Operating Procedures for Taiwan’s Offshore Wind Power Development and An Impact Analysis of Wind Farms on Taipower System." Thesis, 2018. http://ndltd.ncl.edu.tw/handle/659n7g.

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碩士
國立臺北科技大學
電機工程系
107
It has been shown that global on-land wind power development is close to becoming saturated. However, strong and stable wind speeds are available offshore so that offshore wind power is able to produce a large amount of electricity. Therefore, many advanced economies are moving to establish offshore wind capacity, with the goals of building large-scale wind turbines, taller towers and large-scale wind farms far away from the coast. Taiwan, surrounded by sea, has one of the best offshore wind resources in the world. Previous studies have shown that Taiwan’s feasible installed wind energy capacity is 15.2GW. The offshore wind potential gives Taiwan a great opportunity to develop its offshore wind power industry. The Bureau of Energy under the Ministry of Economic Affairs has planned that the installed capacity of offshore wind power should reach 3000MW by 2025. There are numerous plans for offshore wind power development underway. Still, Taiwan has few completed offshore wind project currently in commercial operation so that experience of establishing offshore wind farms is lacking. This thesis has surveyed international wind power generation cases, discussed related regulations, and analyzed several feasibility studies in order to develop operational procedures which can be beneficial for future Taiwan offshore wind power projects. These procedures include site assessment, wind energy assessment, study of policy and regulation, planning and design, construction plan, operation and maintenance, extension and decommissioning. Moreover, a “SOPs for Taiwans Offshore Wind Power Development” website（https://sites.google.com/view/offshoresop）has been launched for public access. In conclusion, as offshore wind farms tend to have larger turbines with higher capacity, they are more likely to make a significant impact when connected to the power grid. In order to reduce undesired consequences when offshore wind turbines are connected to the Taipower Grid System, it is important that developers should carry out comprehensive impact assessments in the planning stage and formulate any necessary measures for improvement while implementing their projects.

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Elkinton, Christopher Neil. "Offshore wind farm layout optimization." 2007. https://scholarworks.umass.edu/dissertations/AAI3289248.

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Offshore wind energy technology is maturing in Europe and is poised to make a significant contribution to the U.S. energy production portfolio. Building on the knowledge the wind industry has gained to date, this dissertation investigates the influences of different site conditions on offshore wind farm micrositing—the layout of individual turbines within the boundaries of a wind farm. For offshore wind farms, these conditions include, among others, the wind and wave climates, water depths, and soil conditions at the site. An analysis tool has been developed that is capable of estimating the cost of energy (COE) from offshore wind farms. For this analysis, the COE has been divided into several modeled components: major costs (e.g. turbines, electrical interconnection, maintenance, etc.), energy production, and energy losses. By treating these component models as functions of site-dependent parameters, the analysis tool can investigate the influence of these parameters on the COE. Some parameters result in simultaneous increases of both energy and cost. In these cases, the analysis tool was used to determine the value of the parameter that yielded the lowest COE and, thus, the best balance of cost and energy. The models have been validated and generally compare favorably with existing offshore wind farm data. The analysis technique was then paired with optimization algorithms to form a tool with which to design offshore wind farm layouts for which the COE was minimized. Greedy heuristic and genetic optimization algorithms have been tuned and implemented. The use of these two algorithms in series has been shown to produce the best, most consistent solutions. The influences of site conditions on the COE have been studied further by applying the analysis and optimization tools to the initial design of a small offshore wind farm near the town of Hull, Massachusetts. The results of an initial full-site analysis and optimization were used to constrain the boundaries of the farm. A more thorough optimization highlighted the features of the area that would result in a minimized COE. The results showed reasonable layout designs and COE estimates that are consistent with existing offshore wind farms.

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邱奕勝. "A Study on Wind Resource Assessment at Offshore Wind Farm Using Windsim - an Example from Changhua Offshore Wind Farm." Thesis, 2018. http://ndltd.ncl.edu.tw/handle/46p5sy.

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碩士
國立嘉義大學
景觀學系研究所
106
The use of renewable energy is rapidly increasing to reduce the impact of global warming. Considering that there is an excellent offshore wind potential in Taiwan Strait, the wind energy resources evaluation becomes important for promoting offshore wind energy. The evaluation of wind energy resources is based on a large amount of measured data. In view of the difficulties in the observation of marine weather and the lack of reliable observation data, this study used reanalysis data (Modern-Era Retrospective analysis for Research and Applications, MERRA), Central Weather Bureau weather station (CWB), Floating Lidar, Taipower Mast, measure correlate predict method (MCP) and Windsim wind energy assessment software. Through the cases of Miaoli and Changhua, we aimed to find out the selection principle of weather station and mesoscale data points. In addition to wind source, annual energy production (AEP), wake loss and operating cost were also analyzed. The result of this study indicated that MCP can improve the accuracy of CWB. However, if the original CWB has high correlation, MCP will reduce CWB correlation. CWB station is recommended to be near the simulated position, offshore, high altitude station; MERRA point selection order is recommended in the offshore waters, close to the simulated position. The more complex the terrain is, the more susceptible the simulated result will be. The simulation result of the Taipower-Changhua-South Wind Farm simulation indicatd that Fangyuan Station figured out averaged wind speed of 12.27 m/s, which is higher than floating lidar with 7.67 m/s and Taipower Mast with 7.63 m/s. It’s the same results from the power density. In addition, the annual energy production of the Fangyuan Station was 403.6GW, and the floating lidar was 258.5GW, Taipower Mast was 251.8GW. The energy cost per kWh for Fangyuan Station was 26.9687 US dollars, floating lidar 42.1124 US dollars and the Taipower Mast 43.2236 US dollars. The wind shear of the land environment is much higher than offshore, leading to high simulated wind resource.

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Chen, Uan-Tang, and 陳元堂. "The Study of Offshore Wind Farm Simulation Combining Wind Farm Level Control." Thesis, 2018. http://ndltd.ncl.edu.tw/handle/q2n48m.

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碩士
國立臺灣大學
工程科學及海洋工程學研究所
107
This study aims to develop wind farm control and power output simulations for offshore wind farm systems, including wind farm models, wake models, wind turbine systems, wind turbine control systems and wind farm control systems. The SimWindFarm wind farm simulation software developed by Aalborg University in Denmark under the European Wind Energy Project (Aeolus FP7) is used to complete dynamic analysis and design of the wind field systems in MATLAB/SIMULINK. The 5MW wind turbine model developed by NREL (National Renewable Energy Laboratory) and the 10MW wind turbine developed by the Technical University of Denmark (DTU) are used for simulated prototype of wind turbine. The model of the wind field is based on the fixed wind direction and average wind speed. The height of the wind field is fixed at the hub height. The wind field model, and the wake effect and mathematical model of the wind turbines group are established by two-dimensional matrix. Simulation and research of the output power produced by the overall wind farm systems are performed under the fixed wind field layout. Finally, under input of different wind conditions, the strategy and theory of wind turbine control and wind farm control are integrated to realize the simulation analysis of the power variation and stability for the overall offshore wind farm systems.

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Lee, John H., and 李振弘. "Offshore Wind Farm Planning and Stability Analysis." Thesis, 2004. http://ndltd.ncl.edu.tw/handle/53849629987381571838.

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碩士
國立臺北科技大學
電機工程系碩士班
92
In Taiwan, there is a large wind energy resource especially around the offshore of west coast in some reports. The capacity is estimated about 2000 MW , wind energy may be developed in the close feature. In this thesis, the renewable energy is compared to wind energy firstly, thereafter the development of European offshore wind farms and wind power technologies are introduced. The offshore wind farm planning strategy is studied with comparing the discrepancies and development of onshore and offshore methods, Meanwhile, a scheduling procedure to plan the construction, transportation and installation of a wind farm is proposed to minimize the risk. The northwest Taiwan case is planning to do the assessment as an example for development. Wind power is an unpredictable and uncontrollable power; the dynamic stability is simulated through a wind model with power system by Matlab Simulink software to check the stability for power system and transmission line failures respectively, such as ground fault, short circuit…etc. In order to understand the tie-in to power system situation, the power flow analysis to study the influences of the power system by PSS/E is performed. Some voltages raised on the substation buses due to the wind power cut in were found that could be depressed to acceptable level by connecting a shunt reactor on appropriated location. The result hopefully to give a reference to planning offshore wind farms.

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Tu, Ze-Zuo, and 凃澤佐. "Effects of offshore wind farm interconnected Taipower system." Thesis, 2012. http://ndltd.ncl.edu.tw/handle/uyp3v9.

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碩士
國立臺北科技大學
電機工程系研究所
100
The study aims at transient and steady state voltage stability analyses of the existing power system in parallel with a hundred wind turbines which each rated at 1.5MW. The wind turbines are connected to 161kV Taixi and Sihu substations with a double-loop transmission lines via a new offshore substation. Two categories of simulation have been completed. The steady state simulations include power flow studies and voltage stability analyses between the wind turbines and existing power system under operation condition at maximum and minimum wind turbine outputs. The fault current and short-circuit capacity have also been calculated when 3 phase fault occurred at offshore substation. Voltage disturbances at existing substations are included in transient studies. When the wind turbine is encounting a gust or blast of winds, the far end turbine group which is connected to the offshore substation with longest transmission lines, has been tripped, the voltage disturbance at existing 161kV substations have been observed. In order to improve the transient voltage stability, a STATCOM rated 50MVAr has been considered to install at offshore substation to compensate active power requirement. The voltage collapse condition and the rotor angle variation of the nearby power generators have been examined when 3-phase fault occurred at offshore substation.

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Hung, Wei-Ping, and 洪維屏. "Analysis of Wave Transformations around Offshore Wind Farm." Thesis, 2008. http://ndltd.ncl.edu.tw/handle/53555754162239059116.

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碩士
國立臺灣大學
工程科學及海洋工程學研究所
96
The objective of the research is to apply Boussinesq equations to develop a series of numerical calculations to simulate the affaction of wavehight changes that because two dimensional wave passing through cylinders. This article is based on the concept of Nwogu (1993) that expressed by random depth and the fourth-order Adams-Bashforth-Moulton predictor-corrector scheme in coordination with source function and proper damping boundary conditions to increase the stability of calculation and to decrease the required processing time.The results are quite well in comparison with previous research. In the numerical calculation,first in the geography of 5 meters depth ,we think about that wave of the period is 3.5 seconds and 5 seconds pass through the cylinders of the radious is 3 meters and make waveheight changing.The two cases that one is setting two cylinders shows the wavehight that in the front of the cylinder is approximately 1.7 times the H0,and another is setting four cylinders shows the wavehight that in the front of the cylinder is approximately 1.8 times the H0. Additionally, the numerical calculation can to simulate that wave pass through a group of cylinders in different depth making wave transformations. So the numerical calculations apply to simulate wave pass through cylinders making wave transformations in constant depth、varying depth .

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Dezem, Bertozzi Junior Otávio José. "A Novel HVDC Architecture for Offshore Wind Farm Applications." Thesis, 2020. http://hdl.handle.net/10754/666063.

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The increasing global participation of wind power in the overall generation ca- pacity makes it one of the most promising renewable resources. Advances in power electronics have enabled this market growth and penetration. Through a literature review, this work explores the challenges and opportunities presented by offshore wind farms, as well as the different solutions proposed concerning power electron- ics converters, collection and transmission schemes, as well as control and protection techniques. A novel power converter solution for the parallel connection of high power offshore wind turbines, suitable for HVDC collection and transmission, is presented. For the parallel operation of energy sources in an HVDC grid, DC link voltage con- trol is required. The proposed system is based on a full-power rated uncontrolled diode bridge rectifier in series with a partially-rated fully-controlled thyristor bridge rectifier. The thyristor bridge acts as a voltage regulator to ensure the flow of the desired current through each branch, where a reactor is placed in series for filtering of the DC current. AC filters are installed on the machine side to mitigate harmonic content. The mathematical modeling of the system is derived and the control design procedure is discussed. Guidelines for equipment and device specifications are pre- sented. Different setups for an experimental framework are suggested and discussed, including a conceptual application for hardware-in-the-loop real-time simulation and testing.

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Chan, Hsun-Chieh, and 詹勳捷. "Study on the Risk Assessment of Offshore Wind Farm." Thesis, 2012. http://ndltd.ncl.edu.tw/handle/47915848937931943039.

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碩士
國立臺灣大學
工程科學及海洋工程學研究所
101
The research focuses on the risk analysis of the construction of offshore wind farm. The relevant literatures of risk assessment of offshore construction are collected firstly. Through the analysis of the collected literatures, the offshore wind farm issues which should be noted during the planning, constructing and operation are identified. And the problems in the different stages when planning, constructing and operating offshore wind farm are figured out. The fault tree and event tree are set up by using the Reliability Workbench software from Isograph Software, according to the identified problems. The fault trees can be used as an important index of the risk assessment management and operation countermeasures in the future. In this study, a fault tree searching system of offshore wind farm is also built. The user can use the editing and querying to set up the required fault tree and to search the fault tree from the database.

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MeharkumarBarapati and 博拉帆. "Mean Wind Speed Comparison and Wind Farm Energy Prediction at Chang-Hua Offshore." Thesis, 2016. http://ndltd.ncl.edu.tw/handle/ut5e9y.

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碩士
國立成功大學
航空太空工程學系
104
A Light Detection and Ranging (Lidar) was set up at Chang-Hua development zone one on the sea. The three days mean wind speeds of WRF (3.33km ＆2 km) simulated and WAsP predicted is compared with Lidar wind speed observations. Based on four wind data sets developed five cases for comparison and found error (%) ＆ R-squared values. Lukang meteorological station 5m height anemometer long term wind data (10- years) is used to predict the wind climate at the domain (13x24 km2), and Fuhai met mast. The yearly variation of wind climate predicted at Fuhai met mast under neutral and stable atmospheric condition. At Fuhai met mast location TGC (Taiwan generation corp.) interested in installing 28 and two demo wind turbines. Two sets of wind farm layouts (0o, 30o and 60o) are design with traditional (SWT 3.6 MW h generator used) and TGC (SWT 4.0 MW h generator used) spacing. Each set of wind farm layouts is designed leading towards 0o, 30o and 60o degrees concerning North, in a clockwise direction as per WAsP. WAsP used to predict the yearly variation of wind farm and wind turbines efficiency (%) ＆ capacity factor (%). The Fuhai met mast at Chang-Hua 26 days (10-Oct-2015 to 5-Nov-2015) wind data categorized as daytime, night time and one day is 24 hours. Totally 78 data points are used to estimate the roughness length (z0), friction velocity (u*), power law exponent (p) and shear stress () at day time, night time, and the whole day (24 hours).

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Chun-JenShih and 施淳仁. "Evaluation of Liquefaction Potential in Western Taiwan Offshore Wind Farm." Thesis, 2013. http://ndltd.ncl.edu.tw/handle/80384543392585073707.

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碩士
國立成功大學
土木工程學系碩博士班
101
As an island country, Taiwan lacks of fossil energy and has to import the energy from abroad. However, there are several places with superior wind energy in Taiwan where located in the coastal, in the offshore and island. Therefore, the development of the wind power to compensate the shortage of fossil energy is inevitable. According to the government plan on renewable energy, Changhua offshore area has been selected as the wind farm for the development of the wind power. There are two sites, Jhangbin site and Fengyuan site, including in the the proposed offshore wind farms. However, Taiwan is located in the seismic belt of western Pacific rim; Several severe earthquake disasters have recorded in the proposed area of the wind farm. Earthquake may cause seabed soil liquefaction. The sea bed liquefaction may damage the structures of the wind turbines and the damage of the structures would cause power plants stop working. Therefore, it is necessary to evaluate the liquefaction potential in seabed soil of the proposed sites. This study uses the simple empirical methods to evaluate the liquefaction potential of the sea bed soil in the offshore wind farm, which including Seed’s simplified method (1997), Tokimatsu and Yoshimi’s method (1983) and the method suggested by NJRA (1996). The ground peak acceleration for which the three empirical methods is needed is computed by three methods, which are NCREE suggested acceleration, attenuation formula and computer program SHAKE. Then, the liquefaction potential index are computed by using Iwasaki’s depth-influence method and set the divisional graphs of liquefaction potential in offshore wind farm. This outcome can be used for design in the offshore wind farm.

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Alasiri, Ali Amer M., and 艾拉斯里. "A Survey on Offshore Wind Farm Technology in the World." Thesis, 2008. http://ndltd.ncl.edu.tw/handle/06346634831332888157.

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碩士
國立臺灣大學
電機工程學研究所
96
In this thesis we focused on survey of feasibility to do the offshore wind farm, also efficiency of doing like this kind of offshore wind farm to reduce the emission of CO2. Hence we have a survey of five projects currently offshore wind farms actual existing in Europe. Whereas it is apparent to us from previous researches that the European projects are the most successful projects around the world during the past few years. We also dealt with two serious reports on offshore wind farms in the U.S.A. They show for us how it is important doing such as this kind of projects. And also we explained in detail these technology: components, machinery work, design, etc... We also do the extensively survey analysis for such as this project. Finally, we used and evaluated the successful experience of these project on the coast of Copenhagen city, Danish. The survey found that wind energy is one of successful solutions for use it as the alternative, clean and renewable energy.

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M, Alasiri Ali Amer. "A Survey on Offshore Wind Farm Technology in the World." 2008. http://www.cetd.com.tw/ec/thesisdetail.aspx?etdun=U0001-3006200810105400.

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