Дисертації: "Wind power plants Victoria"

1

Barry, Martin. "Distributed small-scale wind in New Zealand : advantages, barriers and policy support instruments : a thesis submitted to the Victoria University of Wellington in partial fulfilment of the requirements for the degree of Master of Environmental Studies /." ResearchArchive@Victoria e-Thesis, 2007. http://hdl.handle.net/10063/87.

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2

Shams, Solary Arasto. "Wind power plants integration to the power grid." Thesis, KTH, Skolan för elektro- och systemteknik (EES), 2016. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-200633.

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3

Tamadon, Nahal. "Specification and Classification of Wind Power Plants." Thesis, KTH, Skolan för elektro- och systemteknik (EES), 2016. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-200628.

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4

Montenegro, León Alejandro. "Advanced power electronic for wind-power generation buffering." [Gainesville, Fla.] : University of Florida, 2005. http://purl.fcla.edu/fcla/etd/UFE0010112.

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5

Díaz-González, Francisco. "Contributions of flywheel systems in wind power plants." Doctoral thesis, Universitat Politècnica de Catalunya, 2013. http://hdl.handle.net/10803/129688.

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The stepwise replacement of conventional power plants by renewable-based ones such as wind power plants could a ect the system behaviour and planning. First, the network stability may be compromised as it becomes less resilient against sudden changes in the loads or generator trips. This is because wind turbines are not synchronized with network frequency but they are usually connected to the grid through fast controllable electronic power converters. And second, due to the stochastic nature of wind, the electrical power generated by wind power plants is neither constant non controllable. This aff ects the network planning as the expected generation level depends on non reliable wind forecasts. Also it aff ects the power quality as the fast fluctuations of wind power can cause harmonics and flicker emissions. For these reasons, network operators gradually set up more stringent requirements for the grid integration of wind power. These regulations require wind power plants to behave in several aspects as conventional synchronized generating units. Among other requirements, it is set the provision of some ancillary services to the grid as frequency and voltage control, the capability of withstanding short-circuits and faults, and to respect some threshold level with regard to the quality of the power generated. Accordingly, energy storage systems may play an important role in wind power applications by enhancing the controllability of the output of wind power plants and providing ancillary services to the power system and thus, enabling an increased penetration of wind power in the system. This thesis focuses on the potential uses of flywheel energy storage systems in wind power. The thesis introduces the basis of several energy storage systems as well as identi es their applications in wind power based on an extensive literature review. It follows with the presentation of the design and setting up of a scale-lab flywheel-based energy storage system. From this work, research concentrates on the application of flywheel devices for power smoothing of wind power plants. The developed concepts are proved by simulations but also experimentally using the above mentioned scale-lab test bench. In particular, research focuses on the de nition of an optimization criteria for the operation of flywheel devices while smoothing the wind power, and the design and experimental validation of the proposed control algorithms of the storage device. The last chapters of the thesis research on the role of wind power plants in system frequency control support. In this sense, an extensive literature review on the network operator's requirements for the participation of wind power plants in system frequency control related-tasks is off ered. Also, this review covers the proposed control methods in the literature for enabling wind turbines to participate in system frequency control. The results of this work open the door to the design of control systems of wind turbines and wind power plants for primary frequency control. The contribution of flywheel devices is also considered. Results highlight the tremendous potential of energy storage systems in general for facilitating the grid integration of wind power plants. Regarding the uses of flywheel devices, it is worth noting that some of their characteristics as the high-ramp power rates can be exploited for reducing the variability of the power generated by wind turbines, and thus for improving the quality of the power injected to the grid by wind power plants. Also, they can support wind power plants to ful l the requirements for their participation in system frequency control support related tasks.
El progressiu despla cament de plantes de generaci o convencionals per part de plantes de generaci o de tipus renovable, com els parcs e olics, pot afectar el comportament i la plani caci o del sistema el ectric. Primer, l'estabilitat pot ser compromesa ja que el sistema el ectric resulta m es vulnerable davant canvis abruptes provocats per les c arregues del sistema o desconnexions no programades de generadors. Aix o es degut a que les turbines e oliques no estan sincronitzades amb la freqü encia el ectrica del sistema ja que la seva connexi o es a trav es de convertidors electr onics de pot encia. Segon, degut a la gran variabilitat del vent, la pot encia el ectrica generada per les turbines e oliques no es constant ni controlable. En aquest sentit, la qualitat de la pot encia del parc e olic es pot veure compromesa, ja que es poden detectar nivells apreciables d'harm onics i emissions de "flicker" degudes a les r apides variacions de la pot encia generada pel parc e olic. Per aquests motius, els operadors dels sistemes el ectrics fan gradualment m es restrictius els requeriments de connexi o dels parcs e olics al sistema el ectric. Aquestes regulacions requereixen als parcs e olics que es comportin en molts aspectes com plantes de generaci o convencional. Entre d'altres requeriments, els parcs e olics han de proveir serveis auxiliars per a la operaci o del sistema el ectric com tamb e el suport en el control dels nivells de tensi o i freqü encia de la xarxa; oferir suport durant curtcircuits; i mantenir uns nivells m nims en la qualitat de la pot encia generada. Els sistemes d'emmagatzematge d'energia poden millorar la controlabilitat de la pot encia generada pels parcs e olics i ajudar a aquests a proveir serveis auxiliars al sistema el ectric, afavorint aix la seva integraci o a la xarxa. Aquesta tesi tracta l'aplicaci o en parcs e olics dels sistemes d'emmagatzematge d'energia basats en volants d'in ercia. La tesi introdueix les bases de diversos sistemes d'emmagatzematge i identi ca les seves potencials aplicacions en parcs e olics en base a una extensa revisi o bibliogr a ca. El treball continua amb la posta a punt d'un equipament de laboratori, que con gura un sistema d'emmagatzematge d'energia basat en un volant d'in ercia. Següents cap tols de la tesi estudien l'aplicaci o dels volants d'in ercia per a esmorteir el per l fluctuant de la pot encia generada pels parcs e olics. Els treballs es focalitzen en la de nici o dels criteris per a la operaci o optima dels volants d'in ercia per la seva aplicaci o d'esmorteir el per l fluctuant de potencia e olica, i tamb e en el disseny i validaci o experimental dels algoritmes de control desenvolupats per governar el sistema d'emmagatzematge. Els cap tols finals de la tesi tracten sobre el suport al control de freqü encia per part dels parcs e olics. S'ofereix una extensa revisi o bibliografica respecte els requeriments indicats pels operadors del sistema el ectric en aquest sentit. A m es, aquesta revisi o cobreix els m etodes de control dels parcs e olics i turbines e oliques per la seva participaci o en el suport al control de freqü encia. Les conclusions extretes serveixen per proposar sistemes de control de parcs e olics i de turbines e oliques per proveir el servei de control de freqüencia. Aquest treball, tamb e contempla la inclusi o de volants d'in ercia en els parcs e olics. Dels resultats de la tesi se'n dedueix l'important potencial dels sistemes d'emmagatzematge d'energia per a afavorir la integraci o a la xarxa dels parcs e olics. La controlabilitat de la pot encia dels volants d'in ercia, afavoreix el seu us per reduir la variabilitat de la pot encia generada pels parcs e olics, millorant aix la qualitat de pot encia del mateix. A m es, els volants d'in ercia poder ajudar als parcs e olics a complir amb els requeriments per a la seva integraci o a xarxa, com la participaci o en el control de freqüencia del sistema el ectric.

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6

Li, Pei 1981. "Controlling hour-long power of wind farms." Thesis, McGill University, 2007. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=112574.

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In attempting to control the power output of a wind farm, it is first necessary to smooth the power fluctuations due to wind turbulence. This is accomplished by spatial smoothing, whereby the high frequency power components of a single wind turbine generator (WTG) is reduced by a factor of N-1/2, where N is the number of WTGs in the farm. For this reason the first part of the thesis is concerned with developing a model of smoothing in a wind farm and justifying it mathematically.
After spatial smoothing, the wind farm output still contains low frequency fluctuations. The second part of the thesis makes use of a combination of: (i) pitch angle control of the turbine blades, (ii) power electronic control of the generators, (iii) spatial filtering and (iv) negative feedback control to remove the low frequency fluctuations. The wind farm output then has the quality to be sold as regulated power which fetches a better economic return than when sold as energy. This, of course, presumes that 1-hour ahead prediction of wind velocity at 1-hour long low variance is available.
The thesis also considers the case when the conditions for regulated power are not predicted. In this situation, the wind farm may opt to use the tracking mode which tracks the slowly time varying non-turbulent wind power. The thesis examines the possibility of diverting some of the wind farm power to implement dynamic performance enhancement strategies, for system damping for example.
The controllability of the wind farm is demonstrated by simulations of a wind farm made up of 24 wind turbine-generators (WTGs) using 1-hour long wind velocity data.

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7

Nilsson, Julia. "On maintenance management of wind and nuclear power plants." Licentiate thesis, Stockholm : Skolan för elektro- och systemteknik, Kungliga Tekniska högskolan, 2009. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-11321.

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8

Scott, Ryan. "Characterizing Tilt Effects on Wind Plants." PDXScholar, 2019. https://pdxscholar.library.pdx.edu/open_access_etds/5035.

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Tilting the nacelle of a wind turbine modifies entrainment into the wind plant and impacts total efficiency. Extreme angles can produce flying and crashing wakes where the wake either disrupts entertainment from the undisturbed flow above or is decimated on the ground. The effect of tilt angle on downstream wake behavior was investigated in a series of wind tunnel experiments. Scale model turbines with a hub height and diameter of 12 cm were arranged in a Cartesian array comprised of four rows of three turbines each. Nacelle tilt was varied in the third row from -15° to 15° in chosen 5° increments. Stereo PIV measurements of the instantaneous velocity field were recorded at four locations for each angle. Tilted wakes are described in terms of the average streamwise velocity field, wall-normal velocity field, Reynolds stresses, and mean vertical transport of kinetic energy. Conditional sampling is used to quantify the importance of sweep vs. ejection events and thus downwards vs. upwards momentum transfer. Additionally, wake center displacement and changes in net power are presented and compared to existing models. The results demonstrate large variations in wake velocity and vertical displacement with enhanced vertical energy and momentum transfer for negative tilt angles. Simulation models accurately predict wake deflection while analytic models deviate considerably highlighting the difficulties in describing tilt phenomena. Negative angles successfully produce crashing wakes and improve the availability of kinetic energy thereby improving the power output of the wind plant.

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9

Domínguez, García José Luis. "Analysis of the contribution of wind power plants to damp power system oscillations." Doctoral thesis, Universitat Politècnica de Catalunya, 2013. http://hdl.handle.net/10803/129687.

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Wind power has emerged as one of the most promising renewable energy sources. The very penetration levels of wind energy in power systems have altered several aspects of power system operation, such as system stability. Owing to the large penetration of wind power, transmission system operators (TSOs) have established special grid codes for wind farms connection. These grid codes require wind farms to provide ancillary services to the grid such as frequency and voltage regulation. In the near future, the capability of damping power system oscillations will be required. As a result of the development of such requirements, the concept of wind power plant (WPP) arises being de ned as a wind farm which is expected to behave similarly to a conventional power plant in terms of power generation, control and ancillary services. As future grid codes will require power oscillation damping contribution from wind power, the thesis is mainly focused on the analysis of the power system stabilizer (PSS) capability of wind power plants. The change produced by wind power plants based on di erent wind turbine technologies on power system small signal dynamics is analysed to determine their possible contribution to damp oscillations. The eff ect of the distance from the tie line to the wind power plant on the controller response and the influence of wind power plants proximity to synchronous generators are demonstrated to be critical factors. At this point several questions are raised as: What are the most critical factors? How can be ensure a proper contribution, at least the best possible response? Can it be ensured to be independent to the power system and the controller selected? To answer these questions, this thesis conducts research on proper selection of input-output signal pairs to damp out electromechanical oscillations using wind power plants without drawing attention to a particular control design. This is necessary conclusions about the power system independently of a particular controller. The capability to damp is an intrinsic characteristic of the system and should not be a ected by a particular controller (PSS). Firstly, di erent analysis techniques are compared, considering both controllability and observability measures and input-output interactions. This enables recommendations to be drawn so as to the selection of the the best signal pairs to damp power system oscillations considering di erent approaches, such as single-input single-output (SISO) and multivariable control (MIMO). Second, a new criterion to select the best input-output signals used by a PSS based on WPPs is presented, considering explicitly local and remote signals in the analysis. Taking into account fundamental design limitations and using controllability and observability concepts, the criterion is able to identify the most suitable pair of input-output local signals without consider any particular controller. Finally, due to the increase of wind power generation - including o shore locations - and the concept of an interconnected Pan-European network, a new o shore wind power plant AC network similar in design to the European SuperGrid \SuperNode", is analyzed. The cost e ect of choosing a nonstandard operating frequency on the o shore AC network is investigated. As the o shore AC network is isolated from onshore networks through the use of HVDC links, it may be operated in an asynchronous fashion and at a suitable frequency. The cost associated with operating the network at a fixed frequency in the range 20 to 120 Hz is investigated, focusing on the frequency-cost-scalings of electrical devices (such as cables, transformers and reactive compensation) and the related o shore infrastructures,
L'energia e olica s'ha convertit en una de les fonts d'energia renovable m es prometedores. Actualment, l'elevat nivell de penetraci o de l'energia e olica a la xarxa el ectrica ha conduï t a la modi caci o del comportament de diversos aspectes d'aquesta, com per exemple, l'estabilitat. Degut a aquesta gran penetraci o, els operadors de xarxes de transmissi o (TSOs) han establert procediments d'operaci o especials per a la connexi o de grans parcs e olics. Aquests codis requereixen als parcs elics que realitzin serveis auxiliars al sistema el ectric com, per exemple, la regulaci o de freqü encia i la regulaci o de la pot encia reactiva. En un futur proper, la capacitat dels parcs e olics per esmorteir les oscil lacions del sistema de pot encia es requerir a (en l'actualitat ja existeixen esborranys de nous procediments d'operaci o que ho inclouen). A causa d'aquest requeriments, el concepte de central de generaci o d'energia e olica es de neix com un parc e olic que s'espera que es comporti de manera similar a una central de generaci o el ectrica convencional en termes de poder realitzar tasques tals com generaci o, control i serveis auxiliars. Ja que un futur requeriment dels operadors de xarxa ser a la contribuci o de l'energia e olica en l'esmorteiment de les oscil lacions de pot encia, en aquesta tesi s'estudia la capacitat de les centrals e oliques per actuar com estabilitzador dels sistemes el ectrics de pot encia. A m es a m es, s'analitza l'efecte de les centrals d'energia e olica al comportament din amic del sistema el ectric considerant l'estabilitat de petita senyal, per a determinar quina podr a ser la possible contribuci o proporcionada per aquestes tecnologies. S'ha estudiat que l'efecte de la dist ancia des d'el punt de connexi o amb la central d'energia e olica a la resposta del control estabilitzant i la influ encia de la proximitat de les centrals e oliques als generadors s ncrons s on factors cr tics. D'aquest fet surgeixen algunes preguntes com: Es aquest el factor m es cr tic? Com es pot assegurar una contribuci o adequada, si m es no la millor resposta possible, per ajudar a estabilitzar el sistema el ectric? Es poden asegurar quina ser a la contribuci o a l'estabilitat del sistema el ectric independentment de la xarxa i l'esquema de control escollit? Per respondre a aquestes preguntes, aquesta tesi ha realitzat investigacions sobre l'adequada selecci o de parells de senyals d'entrada-sortida per esmorteir les oscil lacions electromec aniques amb centrals e oliques evitant dissenyar el controlador i propossant met odes f acilment adaptables a qualsevol sistema el ectric. En primer lloc, s'han comparat diferents t ecniques d'an alisi tenint en compte tant les mesures de controlabilitat i observabilitat com les interaccions entre les senyals d'entrada i sortida. D'aquesta comparaci o, certes recomanacions es donen a l'hora de seleccionar els millors parells de senyals per esmorteir les oscil lacions del sistema el ectric de pot encia considerant diferents esquemes de control com ara entrada unica sortida unica (SISO) i control multivariable (MIMO). En segon lloc, s'ha proposat un nou criteri per seleccionar les senyals d'entrada i sortida utilitzades per un control estabilitzador per centrals d'energia e olica. On, a difer encia amb anteriors met odes de selecci o proposats, el criteri presentat considera expl citament tant senyals locals com senyals remotes dins el seu an alisi. Aquest criteri es capa c d'identi car la parella de senyals locals d'entrada i sortida m es adequada sense realitzar el disseny del controlador, considerant tant les limitacions fonamentals del disseny del controlador imposades per el sistema com els conceptes de controlabilitat i observabilitat. Finalment, a causa del augment de la generaci o d'energia e olica, principalment en localitzacions marines, i al concepte d'una xarxa el ectrica comuna Pan-Europea, s'ha realitzat l'an alisi d'un nou concepte de xarxa en corrent altern (AC) dins de les centrals d'energia e olica marina, amb un disseny similar al concepte investigat a la Super-Xarxa Europea \Supernode". En aquest treball s'ha investigat l'efecte que t e en els costos la tria una freqüencia nominal d'operaci o no est andard en dita xarxa en corrent altern. La xarxa en AC que es forma entre les turbines e oliques i el convertidor de transmissi o es aï llada tant de les xarxes terrestres per l' us d'enlla cos en corrent continu (HVDC) com de la pr opia de les turbines per el convertidor que porten incorporat. Aquest fet implica que aquesta xarxa pot ser operada sense sincronitzar a qualsevol freqüencia. En aquesta tesi, s'ha estudiat quin es el cost associat amb l'operaci o de la xarxa a una freqü encia fi xa dins del rang de 20-120 Hz, focalitzant principalment en l'escalat del costos dels diferents elements el ectrics (com ara cables, transformadors i compensaci o reatviva i infraestructures necessaris en instal lacions marines respecte la freqüencia.

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10

Yang, Kai. "On Harmonic Emission, Propagation and Aggregation in Wind Power Plants." Doctoral thesis, Luleå tekniska universitet, Energivetenskap, 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:ltu:diva-18678.

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The increasing use of wind energy is a global trend as part of the overall transition to a more sustainable energy system. By using modern technologies, the wind energy is converted into electric power which is transported to the consumers by means of the electric power system. The use of these technologies, in the meantime, plays a significant role in maintaining power quality in the electric power system; including positive as well as negative impacts. This thesis emphasises on harmonic distortion within a wind power plant (WPP), for a wind turbine and for the plant level.The harmonic study presented in this thesis has been based on field measurements at a few different individual wind turbines and at a second location in one WPP. In general, the levels of harmonic distortion as percentage of the turbine and WPP ratings are low. Among the frequency components, even harmonics and especially interharmonics are present at levels comparable with the levels of characteristic harmonics. The measurements show that both harmonics and interharmonics vary strongly with time. Interharmonics further show a strong dependence on the active power production of the turbine, while characteristic harmonics are independent on the power production. The even harmonics and interharmonics may excite any resonance in the collection grid or in the external grid.The origin of interharmonic emission due to power converters has been verified through a series of measurements over a two-week period. The interharmonic emission originates from the difference between the generator-side frequency and the power system frequency. A series of interharmonic frequencies are produced and they vary in accordance with the generator-side frequency. Both these interharmonic frequencies and the magnitudes are related to each other, and the theoretical relations have been confirmed through the measurements.The harmonic propagation in a collection grid has been studied by using transfer functions. Without the need to know the harmonic sources, the characteristics of harmonic propagations are quantified through transfer functions. The method has been used to estimate the total harmonic level in a WPP, by combining knowledge of the transfer function with information from harmonic emission of the individual wind turbines. The harmonic aggregation of the emission from the individual turbines towards the point of connection (PoC) has been studied as well. From the studies it was found that interharmonics show a stronger cancellation compared to harmonics, especially compared to lower-order harmonics.According to the object of interest and the harmonic propagation, a distinction has been made between primary and secondary emission. A more detailed classification of the different propagations within a WPP has been proposed. A systematic approach for harmonic studies in association with WPPs has resulted from this. The harmonic voltages and currents at any location are obtained as the superposition of the contribution from different emission sources to this specific location. This location can be either within the WPP or in the external grid. The studies presented conclude that all the contributions should be included to get a reasonable overview of the harmonic distortion in the WPP.

Godkänd; 2015; 20150130 (kaiyan); Nedanstående person kommer att disputera för avläggande av teknologie doktorsexamen. Namn: Kai Yang Ämne: Elkraftteknik /Electric Power Engineering Avhandling: On Harmonic Emission, Propagation and Aggregation in Wind Power Plants. Opponent: Professor Roberto Langella, Scientific Responsible of the Second University of Naples local Research Section of EnSiEL, Naples, Italien. Ordförande: Professor Math Bollen, Avd för Energivetenskap, Institutionen för Teknikvetenskap och matematik, Luleå tekniska universitet, Skellefteå. Tid: Fredag 17 april kl 10.00 Plats: Hörsal A, Campus Skellefteå

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Shelley, Dena L. "A wind energy landscape : the Searsburg Wind Park." Virtual Press, 2008. http://liblink.bsu.edu/uhtbin/catkey/1390311.

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Wind Energy facilities are becoming a more common occurrence among the U.S. landscape. The shift to renewable from non-renewable energy sources is an important agenda item for energy policy in the 21st century. Unlike other forms of energy, the unique visual aspects of wind energy provide opportunities to engage with and actually view the process of energy production. The sculptural element of turbines and their placement in highly visible areas, such as mountain ridges, provides opportunities of environmental interpretation and public interaction. Although existing security and safety precautions in the U.S. do not allow public use of these facilities, the integration of turbines into public places is becoming more common in other parts of the world. This creative project focuses on developing dynamic and unique cultural places that also serve as education spaces to celebrate wind and wind energy. Environmental art installations among the wind turbines serve as human-scaled interpretational guides to create meaningful, learning experiences between the user, the wind and the landscape.This project highlights the existing eleven-turbine (6MW) facility in the town of Searsburg in southern Vermont. This project includes inventory, analysis and site design of an existing wind facility. The methodology includes using GIS data and existing sight line data, as well as significant and environmental cultural points. Finally, general guidelines are included as a design foundation for other wind energy facilities.
Department of Landscape Architecture

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12

Brookes, Kate Louise. "Assessment of methods used to investigate the impact of offshore wind farms on seabirds." Thesis, Available from the University of Aberdeen Library and Historic Collections Digital Resources, 2009. http://digitool.abdn.ac.uk:80/webclient/DeliveryManager?application=DIGITOOL-3&owner=resourcediscovery&custom_att_2=simple_viewer&pid=59374.

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13

Edinger, Chad L. "Wind turbine capacity planning approximations for northwest United States utilities." Online access for everyone, 2008. http://www.dissertations.wsu.edu/Thesis/Spring2008/c_edinger_0032608.pdf.

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14

Aragüés, Peñalba Mònica. "Operation and control of transmission systems for offshore wind power plants." Doctoral thesis, Universitat Politècnica de Catalunya, 2016. http://hdl.handle.net/10803/393893.

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This thesis deals with grid integration of oshore wind power plants through HVDC (High Voltage Direct Current) or HVAC (High Voltage Alternating Current) transmission . The behaviour of wind farms and their transmission systems in normal operation and under faults is analyzed. On the eld of HVDC transmission , a control scheme based on an optimum voltage algorithm is proposed and compared to voltage droop control. The dierences between the proposed scheme and droop control in terms of losses are analyzed, in steady state as well as dynamically. This new control scheme is enhanced, being able to perform secondary and tertiary control strategies simultaneously for DC grids. Concerning HVAC transmission, the operation of AC connected wind power plants equipped with full power converter wind turbines is analyzed under deep voltage sags on the main AC grid. Standard control schemes, based on the strict application of grid codes, can lead to instability problems when this kind of severe disturbances occurs. A coordinated control scheme is proposed to operate the system, ensuring fault ride through capability. An index alerts of instability proximity and allows to actívate active power and reactive power regulation to guarantee safe operation during faults. For enabling the optimal operation of transmission systems, an optimal power flow tool is described for hybrid HVDC-HVAC systems, for different objective functions. This tool is tested in a scaled platform. Finally, the secure and optimal operation of these systems is analysed for a scenario with high penetration of oshore wind, proposing a methodology to evaluate the cost of operation and wind energy curtailed.
La present tesi tracta la integració a xarxa de plantes eòliques marines a través de transmissió en HVDC (Alta Tensió en Corrent Continu) o HVAC (Alta Tensió en Corrent Altern). S'analitza el comportament dels parcs eòlics i del seus sistemes de transmissió en condicions normal i en situacions de pertorbacions elèctriques. En el camp de l'HVDC, es descriu un esquema de control basat en un algorisme de tensions òptimes i es compara amb el control de tensió droop. Les diferències entre l'esquema de control proposat i el droop s'analitzen, des del punt de vista de pèrdues, en estat estacionari i dinàmicament. L'esquema de control proposat es millora, oferint la possibilitat de realitzar estratègies de control secundari i terciari en xarxes DC. Dins de la transmissió en l'HVAC, s'analitza l’operació de parcs eòlics equipats amb convertidors de plena potència quan s'esdevenen sots profunds a la xarxa AC. Els esquemes de control estàndards, basats en l’aplicació estricta dels requisits de connexió, poden comportar problemes d'estabilitat transitòria quan s'esdevenen pertorbacions severes. Es proposa un esquema de control coordinat per operar el sistema, assegurant el fault ride through. Un índex alerta de a de la proximitat d'una inestabilitat i permet activar la regulació de potencia activa i reactiva per assegurar l’operació segura durant la falta. Tenint en compte que l’expansió del sistema de transmissió presenta tant enllaços HVDC com HVAC, es desenvolupa una eina per determinar fluxos de potencia òptims en xarxes híbrides HVDC-HVAC, per diferents funcions objectiu. Es realitzen proves experimentals en una plataforma de baixa tensió per comprovar el funcionament d'aquesta eina. Finalment, s'estudia l’operació òptima i segura d'aquests sistemes, per un escenari amb gran penetració d'energia eòlica, proposant una metodologia per avaluar el cost d’operació i la reducció d'energia eòlica produïda.

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15

Schönleber, Kevin. "Control and operation of wind power plants connected to DC grids." Doctoral thesis, Universitat Politècnica de Catalunya, 2018. http://hdl.handle.net/10803/462246.

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Remote offshore wind power plants (WPPs) are being linked through high-voltage de voltage-source converter (VSC-HVdc) transmission to the main grids. The current deployments of HVdc grid connections for offshore WPPs are point-to-point transmission systems. Moreover, WPPs connected to the offshore VSC-HVdc form an offshore ac grid which operates non synchronously to the main grids. lt is characterized by extensive submarine cabling and, in the case offull-scale power converter-based wind turbines, by being purely converter-based. This thesis goes into two main aspects regarding the operation of HVdc-connected WPPs: i) reactive power and voltage control and ii) fault ride through (FRT) in the ac offshore grids. Optimization-based reactive power control strategies are enhanced to the application of an ac grid consisting ofone grid-forming and several grid-connected converters. A reactive power and voltage control method is introduced which aims to increase the annual energy production from a single WPP. In the industrial application, several WPPs might be clustered which leads to multi-layered controllers and operation boundaries. Taking this into account, an operation strategy with reasonable communication requirements is suggested and evaluated against conventional methods . The work further propases a control framework for the grid-form ing offshore VSC-HVdc. Special emphasis is put on the FRT of unbalanced faults in the offshore grid and the provision of controlled currents for ease of fault detection. Furthermore, the internal variables of the offshore modular multi-level VSC-HVdc are analyzed. Moreover, tour FRT strategies for the grid connected converters are evaluated for unbalanced faults in the offshore grid. This consequently implies that control strategies in symmetrical components are considered. Furthermore, the reduction of over-modulation and over-voltages by the power converters in the offshore grid is dealt with.
Los parques eólicos marinos suelen conectarse a redes eléctricas terrestres a través de corriente continua de alta tensión (siglas en inglés: HVdc) utilizando convertidores de fuente de tensión (siglas en inglés: VSC) cuando la corriente alterna de alta tensión (siglas en inglés: HVac) resulta tecnológicamente e económicamente desfavorable. Los parques eólicos conectados al convertidor HVdc marino crean redes eléctricos marinas de corriente alterna que operan asíncronamente a las redes terrestres. Dichas redes se caracterizan por tener cables submarinos, y, en el caso de aerogeneradores con convertidores de plena potencia, resultan en redes constituidas únicamente por convertidores de potencia. Esta tesis investiga dos de los aspectos principales de la operación de parques eólicos marinos conectados en corriente continua de alta tensión: i) la regulación de potencia reactiva y tensión y ii) la operación durante faltas eléctricas en las redes marinas. Se han propuesto estrategias de optimización del control de reactiva para su aplicación a una red ac con varios convertidores conectados. Se ha introducido un método de regulación de potencia reactiva y tensión cuyo objetivo es incrementar la generación eléctrica del parque eólico. En la implementación práctica, varios parques eólicos podrían pertenecer a la misma red lo cual conduce a reguladores multicapas y a la consideración las interfaces entre los operadores. Teniendo esto en cuenta, se propone una estrategia de regulación de potencia reactiva asumiendo unos tiempos de comunicación razonables, y se compara a conceptos convencionales. La segunda parte de la tesis sugiere un método de control para el convertidor marino en secuencia directa e inversa. Está diseñado para la operación normal y la operación durante faltas asimétricas y permite la inyección de corrientes reguladas para la detección de la falta. Además, se analizan las variables internas del convertidor modular multinivel (siglas en inglés: MMC) en estas situaciones. Asimismo, se han evaluado cuatro estrategias de respuesta a faltas asimétricas por parte de los convertidores de los aerogeneradores. Estas estrategias también incluyen el control en secuencia directa e inversa. Finalmente, se investiga la reducción de sobremodulación en los convertidores y sobretensiones en la red marina.
Hochspannungs–Gleichstrom–Übertragung (HGÜ) stellt eine effiziente Lösung zur Netzanbindung weit entfernter Offshore–Windkraftanlagen dar. Die derzeit verwendeten Punkt–zu–Punkt–Anbindungen basieren dabei auf spannungsgeführten Umrichtertopologien. Das seeseitige Wechselstromnetz verbindet die Windkraftanlagen mit der netzbildenden HGÜ–Umrichterstation. Es charakterisiert sich im Vergleich zu gewöhnlichen Netzen durch das ausschließliche Verwenden von Seekabeln und, im Fall einer Verwendung von Windkraftanlagen mit Vollumrichtern, durch das Fehlen gewöhnlicher, direkt gekoppelter Synchrongeneratoren. Die vorliegende Dissertation behandelt zwei Kernaspekte bezüglich dem Betrieb HGÜ–angebundener Windparks: i) die kontinuierliche Regelung der Blindleistung und Spannung und ii) das Umrichterverhalten bei Spannungseinbrüchen aufgrund von Netzkurzschlüssen [engl. fault ride through (FRT)] im seeseitigen Wechselspannungsnetz. Hierfür werden Blindleistungsoptimierungsverfahren präsentiert, die für die Anwendung in Wechselstromnetzen mit einem netzbildenden Umrichter und weiteren netzsynchronen Umrichtern geeignet sind. Die vorgeschlagene Blindleistung– und Spannungsregelungsmethode verringert die Energieverluste im seeseitigen Netz und erhöht damit die Energieausbeute des Systems. Häufig werden verschiedene Windparks zu Clustern zusammengeschlossen, die mehrschichtige Regelungsansätze fordern. Hierfür wird ein weiteres Verfahren vorgeschlagen, das ähnliche Kommunikationsanforderungen wie herkömmliche Betriebsverfahren aufweist, jedoch geringere Verluste verursacht. Die Arbeit untersucht ferner ein dynamisches Regelungsverfahren für den seeseitigen HGÜ–Umrichter. Dabei wird speziell das Verhalten während unsymmetrischer Kurzschlüsse im seeseitigen Netz berücksichtigt. Darüber hinaus wird der Betrieb des modularen Mehrpunktumrichters (engl. MMC) für diese Anwendung analysiert. Bezüglich des Verhaltens netzsynchroner Umrichter während asymmetrischer Spannungseinbrüche im seeseitigen Netz werden weiterhin vier Verfahren untersucht. Diese zielen unter anderem auf die Verringerung von möglicher Übermodulation der Umrichter und Überspannungen im seeseitigen Netz ab.

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16

Palu, Ivo. "Impact of wind parks on power system containing thermal power plants = Tuuleparkide mõju soojuselektrijaamadega energiasüsteemile /." Tallinn : TUI Press, 2009. http://digi.lib.ttu.ee/i/?443.

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17

YANAMANDRA, LAKSHMI NAGA SWETHA. "OPTIMAL ENERGY DESIGN FOR A SYSTEM OF PUMPED HYDRO-WIND POWER PLANTS." Thesis, Högskolan i Halmstad, Akademin för ekonomi, teknik och naturvetenskap, 2018. http://urn.kb.se/resolve?urn=urn:nbn:se:hh:diva-38016.

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SAMMANFATTNING Medvetenhet och oro kring miljöeffekter från utsläpp av växthusgaser och de minskande resurserna av icke förnybara energikällor har ökat de senaste årtiondena. Utvecklingen av ny teknologi för förnybar energi har drivits fram globalt som ett svar på denna oro. Det har skett stora framsteg i produktion av el och värme från sol, vind, hav, vattenkraft, biomassa, geotermiska resurser, biobränslen och väte. Följaktligen har utvecklingen av energi-lager blivit en viktig del för integration av förnybar energi i systemen. Det är gynnsamt för hela försörjningskedjan, för pålitlighet och bättre stabilitet i leveranser och distribution, och för ökad el-kvalitet. I uppsatsen undersöks en optimal energidesign för ett kombinerat system med vattenkraft och vindkraft inklusive ett lager i form av en damm. Vatten som pumpas upp till lagret har en stor och balanserande potential för att få in en högre grad förnybar energi i energisystemen. Detta är nödvändigt då dessa energikällor är intermittenta och variabla till sin natur. Ett av de studerade objekten är ett vattenkraftverk med pumpad damm, Tehri i Uttarakhand, Indien. Systemets totala verkningsgrad om 93 % diskuteras utifrån förluster såväl som potentialen för vind och dess inverkan. Vind-data är hämta från National Institute of Wind Energy (NIWE) och har analyserats med programmen MATLAB och WindPro. Det slutligen valda området för exploatering av vindkraft blev Ramakkalmedu, Idukki district, Kerala, Indien. Efter valet av plats valdes tre olika vindturbiner ut för analys; Siemens SWT-3.2-113 3.2 MW, Enercon E-126 4.2MW, och Enercon E-126 7.58MW. Analysen består av flera delar; vindparks-modellering, beräkning av buller-generering från vindkraften, beräkning av årlig energi-generering - Annual Energy Production (AEP), kapacitetsfaktor, vindparkens effektivitet med hänsyn tagen till lagret/dammens variation av bas-last. Resultat har erhållits från alla tre turbinerna och den övergripande slutsatsen är att kombinationen med vatten- och vindkraft med lagring av vatten som pumpas upp vid behov är en tillfredsställande metod för att möta belastningstoppar, vilket valideras av denna uppsats. Nyckelord: pumpade vattenkraftdammar, vindkraftparker, energi lager, förnybar energi.
ABSTRACT Awareness and concern regarding the environmental effects of greenhouse gas emissions and depletion of non-renewable energy sources has increased over the last decades. A considerable development of new technology for renewable energy has occurred globally as an answer to this concern. There has been a major progress in production of electricity and heat generated from solar, wind, ocean, hydropower, biomass, geothermal resources, and biofuels and hydrogen. Consequently, the development of energy storages has become an imperative part, for integration of renewable energy. It is beneficial for the entire supply chain, for dependability and better stability, and for enhanced quality of electrical power. This thesis is exploring an optimal energy design for a system of pumped hydro-wind power plants including storage. Solutions with Pumped Hydro Storages have a great potential for their balancing role necessary for a higher degree of renewable energy sources, RES, in the energy systems because of the intermittent and variable nature of these sources. Tehri pumped hydro storage plant, in Uttarakhand, India is one of the objects studied in this thesis. The systems total efficiency of 93%, calculated from head losses, is discussed as well as wind potential and its impact. Wind data is obtained from National Institute of Wind Energy (NIWE) and analysed using the software tools MATLAB and WindPro. The finally chosen area explored for wind potential is Ramakkalmedu, Idukki district, Kerala, India. After selection of site within the area, three different turbines; Siemens SWT-3.2-113 3.2 MW, Enercon E-126 4.2MW, and Enercon E-126 7.58MW were considered for analysis. The analysis consists of several parts; Wind farm modelling, Noise estimation of Wind Park, estimation of Annual Energy Production (AEP), Capacity factor, Wind park efficiency with respect to the storage/reservoir´s base load variation. Results are achieved for all three turbines. The overall conclusion is that combined hydro and wind power with a pumped storage, is a satisfactory method for bulk energy store to address peak loads, which is validated by this thesis. Keywords: Pumped Hydro, Wind farm, Energy Storage, Renewable Energy.

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18

Pastukhov. "World development of wind power plants as an example of cosmopolitan patriotism." Thesis, Сумський державний університет, 2013. http://essuir.sumdu.edu.ua/handle/123456789/31688.

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It is known that the education of patriotism begins with understanding the values of the fatherland. Love and devotion to the Motherland formed with appreciation of beauty their homes, with a love of trees, flowers and peace of father's house. When you are citing the document, use the following link http://essuir.sumdu.edu.ua/handle/123456789/31688

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19

Cohen, Joshua B. "Kruiedokters, plants and molecules : relations of power, wind, and matter in Namaqualand." Doctoral thesis, University of Cape Town, 2015. http://hdl.handle.net/11427/19952.

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This thesis was born out of the post-Mbeki era and the prevailing, tense relationship between 'traditional' healing and biomedical science in South Africa. Attempting to imagine this relationship differently, and as part of an interdisciplinary project, it is based on eleven months of ethnographic fieldwork centring round villages in the Kamiesberg municipality, Namaqualand. Part of the project involved molecular biologists seeking bioactive compounds in locally growing plants. Many of these species were also used by local kruiedokters (herbdoctors), with two of whom, 'Koos' and 'John', the author spent a large proportion of his research time. The thesis addresses the following constructivist questions: what kinds of realities are being done as kruiedokters and molecular biologists work in their own ways with plants? How might these realities - and the similarities and differences between them - be researched, understood and described in ways that rely neither on absolute relativism, nor on one kind of reality trumping all others? Exploring the work of one of the molecular biologists, the thesis argues that the world cannot be entirely encompassed by the matter or pure physicality of modernist metaphysics. This raises the possibility of other modes of existence - modes that people have long considered imperative to human well-being: e.g. in the work of kruiedokters, who specialise in curing people of illnesses and ailments associated with toor (witchcraft/magic). In order not to unfairly reduce these phenomena to belief or superstition, three of the five chapters attempt to attune to the ways in which three vital concepts - krag (power/vitality/strength), toor, and wind (wind), which are central to the work of kruiedokters - exist in people's lives. Attuning meant following, in research and description, the living ecologies of relations through which krag, toor, and wind subsist. While belief can be understood to be part of the relational field, it is as much the constricting force of jealous, poisonous relations themselves that block people's lives. To free patients of these blockages, kruiedokters bring the force of their personality, the cleansing effects of plants, as well as their own ecologies of relations to bear on the therapeutic contexts in which they work. If this succeeds, patients are drawn into a new set of protecting relations that cultivate feelings of krag - enabling patients to move forward with their lives. This poses the challenge that these relations, this work of kruiedokters, this krag, can be understood as being of central importance to human life - and not just as colourful cultural additions to an objectively known world of pure physicality. Studying the interplay of different modes of existence in therapeutic contexts is suggested as a possible way to carry out future, non-reductive collaborations between biomedicine, plant science, and 'traditional' medicine.

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Broders, Adam C. "Combining of renewable energy plants to improve energy production stability." Worcester, Mass. : Worcester Polytechnic Institute, 2008. http://www.wpi.edu/Pubs/ETD/Available/etd-042908-132847/.

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21

Prada, Gil Mikel de. "Design, operation and control of novel electrical concepts for offshore wind power plants." Doctoral thesis, Universitat Politècnica de Catalunya, 2014. http://hdl.handle.net/10803/277427.

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Offshore wind is an emerging energy sector with a huge potential to be tapped in the near future. Offshore Wind Power Plants (OWPPs) are becoming increasingly relevant in Europe and worldwide mainly because the wind speeds are potentially higher and smoother than their onshore counterpart, which leads to higher wind power generation. Moreover, OWPPs have less space limitations constraints, so that it allows the possibility of using larger wind turbines. Nowadays, environmental and social aspects are forcing OWPPs to be constructed further from shore, (which usually leads to deeper waters) and the trend is expected to continue in the coming years. Several studies have demonstrated that if the distance between an OWPP and its grid connection point at the Point of Common Coupling (PCC) exceeds a certain critical distance (approximately 55-70 km), HVDC transmission becomes a more interesting solution than HVAC, since reduce cable energy losses and decrease reactive power requirements. This trend towards larger OWPPs located further away from shore is posing some technical, economic and political challenges that must be overcome to be fully competitive in the longer term compared to other energy sources. Today, there is an important concern about reducing the current Levelised Cost Of Energy (LCOE) of offshore wind projects by improving system reliability and availability, reducing O&M costs and/or increasing energy generation. This thesis aims to propose novel electrical WPP concepts more cost-effective than the existing ones and to comprehensive analyse their technical and economic feasibility. Specific challenges related to the design, optimisation, modelling, operation and control of these new concepts will be addressed in the study. All the concepts presented throughout this thesis, are focused on the collector grid of an OWPP, which encompasses all the necessary equipment to collect the power generated by the wind turbines and to export it to the offshore transmission HVDC platform. The first novel WPP concept assessed can be applied to either an onshore or offshore WPP with a MVAC collection grid connected to the grid through either an HVAC or HVDC transmission link, whilst the rest of the OWPP configurations analysed are motivated by the presence of HVDC technology and its ability to electrically decouple the OWPP from the onshore power system. Thus, the first wind power plant concept evaluated consists in properly derating some specific wind turbines in order to reduce the wake effect within the collection grid and, therefore, to maximise the energy yield by the whole wind power plant during its lifetime of the installation. The following three OWPP concepts analysed arise thanks to the opportunity provided by HVDC technology to operate the collection grid at variable frequency. Thus, the second proposed OWPP concept investigated is based on removing the individual power converter of each wind turbine and connecting a synchronous generator-based OWPP (or a wind turbine cluster) to a single large power converter which operates at variable frequency. Likewise, the third OWPP configuration assessed deals with the optimisation of this aforementioned concept and with the proposal of an hybrid MVAC/MVDC OWPP concept for the offshore collection grid. Regarding the fourth OWPP design, it consists of a DFIG-based OWPP with reduced power converters (approximately 5% of rated slip) connected to a single HVDC substation. This proposal is analysed both static and dynamically by means of simulations. Finally, the last novel OWPP concept presented in this thesis deals with the analysis of an entire offshore wind power plant in DC, with the aim of reducing the losses both in the inter-array and the export cable(s). In general terms, all the novel OWPP concepts analysed suggest a good potential to be applied to future offshore wind power plants by reducing in all the cases the LCOE in comparison with the existing OWPPs.
La energía eólica marina es un sector emergente que se encuentra en plena expansión. Múltiples circunstancias tales como que cada vez sea más difícil encontrar lugares propicios en tierra (principalmente en Europa) para la instalación de parques eólicos, que a medida que el parque se aleja de la costa el impacto visual y auditivo es menor y que en el mar el viento sopla con más intensidad y de una manera más constante que en tierra, lo cual posibilita obtener una mayor generación de energía eólica, han provocado que cada vez existan más parques eólicos marinos. Hoy en día, factores medioambientales y sociales están obligando a construir los parques eólicos marinos cada vez más alejados de la costa y se espera que esta tendencia continúe en los próximos años. Varios estudios han demostrado que a partir de una cierta distancia crítica entre el parque eólico y su punto de conexión a tierra (aproximadamente 55-70 km), la transmisión mediante alta tensión en corriente continua (ATCC) resulta una opción más interesante que a través de una transmisión en alta tensión de corriente alterna (ATCA), ya que las pérdidas en los cables se ven reducidas, así como los requerimientos de potencia reactiva. Esta tendencia hacia construir parques eólicos marinos cada vez mayores y a ubicarlos más alejados de la costa, supone el tener que resolver ciertos retos técnicos, económicos y políticos a fin de poder ser más competitivos en el futuro en comparación con otras fuentes de generación de energía. Hoy en día existe una importante preocupación por tratar de reducir el elevado coste actual de la energía para los proyectos de eólica marina a base de mejorar la fiabilidad y disponibilidad del sistema, reducir costes de operación y mantenimiento y/o incrementar la generación de energía. Esta tesis tiene como objetivo proponer conceptos eléctricos novedosos, aplicados a parques eólicos marinos, que resulten más rentables que los existentes actualmente. Asimismo, esta tesis pretende analizar de una manera exhaustiva la factibilidad, tanto técnica como económica, de dichos conceptos. Asuntos tales como el diseño, la optimización, el modelaje, la operación y el control son presentes en la tesis. El alcance del trabajo se focaliza en la zona colectora de un parque eólico y, por lo tanto, no se analiza, el sistema de transmisión ni su integración a la red. Dicha zona comprende todo el equipamiento necesario para recolectar la potencia generada por los aerogeneradores y transmitirla a la plataforma marina de ATCC. El primer concepto innovador de parque eólico evaluado puede ser aplicado tanto en parques situados en tierra como en el mar, que tengan una red colectora interna de corriente alterna en media tensión (MTCA) y un sistema de transmisión tanto ATCC o ATCA. Respecto al resto de configuraciones presentadas, estas vienen motivadas por la presencia de la tecnología ATCC y su capacidad para desacoplar eléctricamente la red interna del parque eólico del sistema eléctrico de potencia situado en tierra. Así pues, la primera propuesta de parque eólico a analizar consiste en operar algunas máquinas concretas por debajo de su punto óptimo de operación a fin de poder reducir el efecto estela dentro del parque y poder así maximizar la potencia total extraída por el mismo. Las tres siguientes configuraciones de parque analizadas se fundamentan en la posibilidad que ofrece la tecnología ATCC de poder operar la red interna del parque eólico a una frecuencia variable. En base a este nuevo concepto, la segunda propuesta de parque investigada consiste en prescindir de los convertidores individuales de cada turbina y conectar todos los generadores síncronos del parque eólico (o un simple grupo de máquinas) directamente al convertidor central, el cual opera a frecuencia variable. El tercer diseño de parque eólico se basa en una topología híbrida dentro del parque combinado MTCA y MTCC. Esta configuración surge de optimizar la propuesta anterior de parque eólico. Asimismo, la cuarta propuesta a analizar estudia la posibilidad de tener un parque consistente en generadores de inducción doblemente alimentados conectados a un convertidor común de tensión controlada situado en la plataforma marina, en el cual los convertidores de cada máquina sean de un tamaño menor a lo habitual (aproximadamente a un deslizamiento nominal de un 5%). Este sistema es analizado en detalle tanto estática como dinámicamente. Finalmente, el último concepto que se presenta en esta tesis analiza la posibilidad de considerar un parque eólico marino completamente (transmisión y red interna del parque) constituido mediante tecnología en CC, con el fin de poder reducir las pérdidas tanto en la red interna del parque como en el cable de exportación. En términos generales se puede concluir que todos los conceptos propuestos a lo largo de esta tesis sugieren un gran potencial para poder ser aplicados en futuros parques eólicos marinos, ya que su coste de energía se ve reducido en comparación con los parques eólicos existentes hoy en día.

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Raza, Muhammad. "Offshore grid control of voltage source converters for integrating offshore wind power plants." Doctoral thesis, Universitat Politècnica de Catalunya, 2017. http://hdl.handle.net/10803/461835.

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The offshore grid in North and Baltic Sea can help Europe to achieve 2020 and 2030 renewable energy target to counter climate changes . The formation of offshore grid requires the interconnection between several offshore wind power plants with multiple onshore grids. A voltage source converter based high voltage direct current transmission system is suitable to operate such an integrated offshore network. The offshore grid will enhance the trade between countries, provide better infrastructure for offshore wind power plants integration, and improve the energy market. This thesis presents the control system design of voltage source converter to operate an offshore grid. The offshore grid is built gradually , starting from the integration of a single offshore wind power plan! till combined offshore AC and OC network in arder to perform the power system analysis associated with the networks such as steady-state power flow, dynamic behavior, network stability, and short circuit response. The research presents the method of determining control parameters with respect of power distribution and network stability requirements. The research presents the frequency and voltage droop schemes to enhance the grid-forming mode of voltage source converter to operate in parallel in the offshore grid. A multi-objectives optimal power flow algorithm is proposed to determine the frequency and voltage droop gains in order to control the active and reactive power distribution among converters. Later, the impact of these droop gains on network dynamics and stability are analyzed. The study shows that the converter performance influences the offshore AC network stability in conjunction with the droops control loop. Furthermore, a short circuit and frequency coordinated control schemes are presented for both offshore wind generation units and grid-forming converters . The frequency coordinated control scheme reduces !he wind power up to the maximum available export capacity after the disturbance in the offshore grid. lt is suggested that !he coordination control mus! have both frequency and over voltage control for improved transient response. In the end, converter control of mullí-terminal OC network and its integration with the offshore AC network has been presentad. The research demonstrate the converter ability to control the distribution of power among the transmission system while ensuring the network stability. The finding of the research can be applied to derive the information and recommendation for the future wind power plants projects.
Las redes eléctricas marítimas en el Norte y en el Mar Báltico pueden ayudar a Europa a conseguir los objetivos para 2020 y 2030 de combatir el cambio climático. La formación de la red eléctrica marítima requiere la interconexión entre varios parques eólicos marinos con múltiples redes eléctricas en tierra. Un convertidor de la fuente de voltaje basado en el sistema de transmisión de corriente directa de alto voltaje es el apropiado para poder operar una red marítima integrada. Las redes eléctricas marítimas aumentarán el comercio entre países, proveerán una mejor infraestructura para la integración de los parques eólicos marinos y mejorarán el mercado energético. Esta tesis presenta el diseño del sistema de control del convertidor de las fuentes de voltaje para operar una red eléctrica marítima. La red eléctrica marítima se construye gradualmente, empezando por la integración de un solo parque eólico marino hasta la combinación de redes eléctricas marítima en CA y CD, esto para mejorar el análisis del sistema de potencia asociado con las redes, tales como el flujo de potencia en estado estacionario, el comportamiento dinámico, la estabilidad de la red y la respuesta en corto circuito. La investigación presenta el método de determinación de parámetros de control con respecto a la distribución de potencia y los requerimientos de estabilidad de la red. La investigación presenta los esquemas de frecuencia y la caída de voltaje para mejorar el método de formación de red del convertidor de la fuente de voltaje y operar en paralelo con la red eléctrica marítima. Se propone un algoritmo de múltiples objetivos para lograr un flujo de potencia óptimo, determinar las ganancias en la frecuencia y en la caída de voltaje y así lograr controlar la distribución de potencia activa y reactiva entre los convertidores. Después, se analiza el impacto de estas ganancias en la dinámica y estabilidad de la red. El estudio nos muestra que el desempeño del convertidor influencia la estabilidad de la red eléctrica marítima en CA en conjunto con el lazo de control de la caída. Así mismo, se presentan los esquemas de control coordinado de frecuencia y corto circuito, aplicados para las unidades de generación eólica marítima y los convertidores en red. El esquema de control coordinado de frecuencia reduce la potencia eólica hasta la máxima capacidad de exportación disponible después de las perturbaciones en la red eléctrica marítima. Se sugiere que la coordinación del control debe de tener control sobre la frecuencia y el sobre voltaje para mejorar la respuesta en transitorios. Por último, se presenta el control del convertidor de las multiterminales en la red CD y su integración con la red eléctrica marítima en CA. La investigación demuestra la habilidad que posee el convertidor para controlar la distribución de potencia, junto con el sistema de transmisión, mientras se asegura la estabilidad de la red. Los hallazgos de esta investigación pueden ser aplicados para obtener información y recomendaciones en los futuros proyectos de parques eólicos.

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23

Merante, Marco. "Application of dynamic rating to improve transportation capability of the power systems connected to wind power plants." Thesis, KTH, Skolan för elektro- och systemteknik (EES), 2016. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-200930.

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Current flow in the electrical grid is changing due to the introduction of new generators and loads.Specifically, weak Overhead lines, are a constraint for the introduction of wind farms located farfrom the central network. The current situation requires smart solutions to improve the transportationcapabilities of these grid’s components. Among the different possibilities, Dynamic Line Rating(DLR), is emerging as the most interesting solution from both the economic and technical points ofview. The presented Thesis work investigates the performance of DLR from both the theoretical andpractical perspectives.The theory behind DLR is based on the development of a thermal model able to estimate the precisetemperature experienced by OHLs conductor under different climate conditions. Since 1972, whenthe first investigation on DLR have been published, different thermal models have been developed,each with a different precision level. The first part of the thesis concerns the investigation of IEEE738 standard accuracy.The standard analysis highlighted weaknesses on the theoretical approach employed on the forcedconvective cooling calculation. Specifically the wind direction effect is estimated as the conductorwas a perfect cylinder. A wind tunnel test has been performed in order to verify the effect of theconductor’s strands on the total thermal equilibrium. The results show that an inclined wind-conductor relative direction can have a more important impacton the line rating than foreseen with the IEEE thermal model. Since the wind tunnel test has been thefirst experience of this kind pursued at KTH, the presence of few different laboratory set-updeficiencies did not allow to draw a definitive and precise conclusion on the necessary IEEE formulacorrection.The practical side of the Thesis project includes an extensive literature research on the differentdevices that can be employed for dynamic line rating and a real-case study analysis. The analysis isperformed in order to evaluate which can be the best solution when the introduction of new windenergy supply increase the load on a pre-existent OHL. Results show that, in the selected region,Värmland, in the southwestern Sweden, DLR has the prerequisites to allow the exploitation of thehigh wind energy resource at the lower expenses. Wind energy production is often associated with anincreased cooling on the line’s conductors. This means that higher current levels can be withstoodavoiding the need for expensive lines’ upgrading. For the selected hot-spot, in 2015, DLR wouldhave allowed a transport capability improvement of 69.6% during the summer and of 26.7% duringthe winter. It is also reported that a load equal to the SLR during the winter period would have causedserious overheating transients of the conductor. Overall DLR proved to allow technical and economicbenefit for the system operator.
Flödet genom elnätet förändras på grund av införandet av ny generering och nya typer av laster.Specifikt är svaga luftledningar en begränsning för installation av vindkraft som ligger långt fråndet centrala nätet. Den nuvarande situationen kräver smarta lösningar för att förbättratransportkapaciteten i elnätet. Bland de olika möjligheterna finns Dynamic Line Rating (DLR) somframstår som den mest intressanta lösningen från både ekonomiska och tekniska synvinklar. Det härexamensarbetet behandlar resultatet av DLR från både teoretiska och praktiska perspektiv.Den teoretiska grunden för DLR är baserad på utvecklingen av en termisk modell som kan skattatemperaturen i luftledningar under olika klimatförhållanden. Examensarbetets första del behandlaren undersökning av IEEE 738 standarden (DLR standard). IEEE 738 standarden utgår från ledarensom en perfekt cylinder. Något som har en effekt bland annat i effekten av vindriktning. Ettvindtunnel test har utförts för att verifiera effekten av fler kardelers effekt på den totala termiskajämvikten. Resultaten visar att antalet kardeler har en betydande effekt på den termiska jämviktenoch då alltså även på DLR.Den andra delen av examensarbetet innehåller en omfattande litteratursökning på de olikaapparaterna som kan användas till DLR samt en praktik undersökning/analys. Analysen utförs föratt utvärdera vilken lösning som kan vara den bästa vid införandet av mer vindkraft, som ökarbelastningen på en redan existerande luftledning. Resultaten visar att, i det valda området,Värmland, i sydvästra Sverige, har DLR förutsättningar för att medge ökat utnyttjandet av den storavindkraft resurs som finns där till relativt låga kostnader. Slutsatsen av examensarbetet är att DLR ger tekniska och ekonomiska fördelar tillsystemoperatören.

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24

Agabus, Hannes. "Large-scale integration of wind energy into the power system considering the uncertainty information = Elektrituulikute integreerimine energiasüsteemi arvestades informatsiooni mittetäielikkust /." Tallinn : TUT Press, 2009. http://digi.lib.ttu.ee/i/?446.

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25

Geary, Ryan D. "A review of offshore wind technology and the development of the Virginia coastline and outer continental shelf /." Full-text of dissertation on the Internet (1.84 MB), 2009. http://www.lib.jmu.edu/general/etd/2009/Masters/Geary_RyanD/gearyrd_masters_12-10-2009_01.pdf.

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26

Li, You. "Application of GIS tools in locating onshore wind power plants – A case study of Västmanland County, Sweden." Thesis, KTH, Mark- och vattenteknik (flyttat 20130630), 2013. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-171850.

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A rapid development of wind energy has been approved globally within the last few years due to the common recognition of this renewable energy technology. It is seen as one of the most promising substitutions to fossil fuels which have been exploited for over one century but were proved to be a crucial factor of human-induced climate change. However, even though wind energy has been regarded to be clean, resource saving and environmentally friendly, it still poses special problems and concerns to the surrounding social-ecological system. Thereby it requires careful selection of sites of installation. This paper provides an overview of wind energy and its development in the recent decade and focus on elaborating different issues involved in wind energy development. This is done through a case study of applying GIS tools in selecting suitable locations for onshore wind power plants in Västmanland County of Sweden.

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27

Mauger, Léo. "Generation of wind speed and solar irradiance time series for power plants with storage." Thesis, KTH, Energiteknik, 2016. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-181923.

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Sizing renewable energy power plants with storage devices needs new resource assessment. Global amount of energy available has to be replaced by time series to depict the resource as a function of time. This paper introduces methodology to generate time series for wind speed and solar irradiance with a granularity between 10minutes and 1seconde. Ground measurements and macro-date from satellite imagery are analyzed and processed to obtain long-term site-specific time series. Because renewable energy forecasting is a growing concern, a second part of the work presents how to modify previously generated profiles in order to obtain forecasts with an expected error.

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Ershad, Ahmad Murtaza. "Potential of Solar Photovoltaic and Wind Power Plants in Meeting Electricity Demand in Afghanistan." University of Dayton / OhioLINK, 2014. http://rave.ohiolink.edu/etdc/view?acc_num=dayton1398944251.

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29

Storgärd, Per. "Grid Optimization Of Wind-Solar Hybrid Power Plants : Case Study Of Internal Grid Connections." Thesis, Uppsala universitet, Institutionen för geovetenskaper, 2016. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-319385.

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Hybrid renewable energy systems (HRES) have proven to be a more stable and feasible source of energy than heir single source counterparts. The benefit of HRES is their ability to balance the stochastic behavior of wind and solar production. As result of this, they have been used as stand-alone systems with great success. Optimization studies in the field have shown optimum sizing of the components in the system to be a key element in order to increase feasibility. This paper focuses on the HRES impact on internal grid design and cost. The goal of the thesis is to create a mathematical function and graph on the internal grid design/cost relation for a virtual site with varying wind speed and solar irradiation. A secondary goal is to analyze how much Photovoltaics (PV) in Megawatt (MW) that can be connected to the internal grid post realization of the wind farm and to performed this analyze on the two specific case projects, Site A (17.25 MW) in Sweden and Site B (51.75 MW) in Italy. By utilizing a case study methodology, a mathematical model was created based on two case projects, both with potential to be a combined Wind-PV hybrid plants provided by the wind developer OX2. Identifiers for the two cases studied in this thesis where removed with respect to OX2’s ongoing projects. Hybrid renewable energy systems is a method of increasing the utilization of a regions RES, the system has an increase in overall power output compared to the single RES alternative. However, the internal grid cost was shown to be 3.85 % more expensive Site A and 5.3 % in Site B. This stood in direct correlation to the HRES in Site A using 8.6 % more cable for its internal grid and 29.7 % more in Site B, this is highly depending (depending on the location of the PV array). Furthermore, the case projects showed that the maximum PV to be connected post realization of the farm without major curtailment would be 11.5% of the wind farms rated power in the case of site A and 67.6 % in the case of Site B. Variations in wind speed and solar irradiation were shown to have some impact on grid cost. However, the results pointed out that grid cost in HRES is to a higher degree affected by total cable length in the internal grid than fluctuation in available energy sources. The extent of increase in cable length, the total grid investment cost rises up to 53.4 % for the two case projects.

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30

Keeli, Anupama. "Low frequency transmission for remote power generating systems." Thesis, Georgia Institute of Technology, 2011. http://hdl.handle.net/1853/41190.

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The goal of this Masters Thesis research is to evaluate alternative transmission systems from remote wind farms to the main grid using low-frequency AC technology. Low frequency means a frequency lower than nominal frequency (60/50Hz). The low-frequency AC network can be connected to the power grid at major substations via cyclo-converters that provide a low-cost interconnection and synchronization with the main grid. Cyclo-converter technology is utilized to minimize costs which result in systems of 20/16.66 Hz (for 60/50Hz systems respectively). Low frequency transmission has the potential to provide an attractive solution in terms of economics and technical merits.

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31

Stenneken, Christian. "Planung und Genehmigung von Windkraftanlagen : unter besonderer Berücksichtigung Nordrhein-Westfalens /." Frankfurt am Main [u.a.] : Lang, 2000. http://www.gbv.de/dms/spk/sbb/recht/toc/314687904.pdf.

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32

Cruickshank, Kyle Mark. "The perceived visual impacts and attitudes of the Grahamstown community towards the Waainek Wind-Farm." Thesis, Rhodes University, 2014. http://hdl.handle.net/10962/d1011768.

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Renewable energy has become an important feature of most modern economies with clean and non-exhaustible sources of power being given a greater significance. Wind energy is one of the favoured renewable, as it is (2013) generally the cheapest and most mature technology available for commercial use. The South African government, as outlined by the Department of Energy's Integrated Resource Plan (IRP), aims to install 5 GW (Gigawatts) of wind energy by 2020. However, South Africa has had little experience in the wind energy industry which is limited to two projects, Klipheuwel (2002) and Darling (2008). Much effort has been dedicated to calculating balance sheet costs, which carries uncertainty due to the high reliance on country specific and site specific variables. An aspect which deserves more attention, and is often ignored, is the public‟s attitudes towards local wind farm developments, which have been known to "make or break" a project during the planning stages. Public backlashes have mostly been concerned with the visual "intrusiveness" of wind farms in the landscape. Detrimental effects on scenery, while seemingly innocuous, are acknowledged as being the single largest barrier to successful wind farm development. Individuals within an area become sentimentally attached to their surroundings, where significant rapid changes in the landscape are viewed as "damage". Economics recognises such declines in scenic resources as market failures, where an externalised cost is passed on to the public and is often not accounted for by private parties responsible for the liability. The primary objective therefore was to measure the magnitude of the visual impact, caused by the Waainek Wind Farm, on the Grahamstown community. Conventional NIMBY¹ (not in my back yard) reasoning, which seeks to explain local wind farm resistance, has attracted criticism with regard to its simplistic approach to wind farm problem identification. Contemporary arguments propose that NIMBY is a poor explanation for the trouble experienced on the local level because it groups problems into one all-encompassing term, leaving much of the discontent unexplained. Instead, the NIMBY explanation is really a broad set of unattended problems, largely resulting from the unsound practices present in the public participation process. Insufficient community involvement and disparities in the negotiation power structures have become the recent focus in wind farm literature. Essentially, these disparities force opposition groups to select factors which may seem more serious to developers, leading to ineffective remedial measures because the core underlying problems are not being remedied. Thus these considerations formed an additional area of investigation. No NIMBY effect was found for the Grahamstown community, as support for both the local and general level was roughly 80%. The public participation process on the other hand revealed that while many found the practices of the developer to be unfair, attitudes towards the wind farm were not adversely affected, especially for the lower income Grahamstown East areas. While the public participation process in this instance did not have any effect on people’s attitudes, careful inspection of the circumstances need to be given. Wind farms are new to South Africa, where the novelty and benefits are the focus of enthusiasm. Job opportunities as well as clean energy are positive drivers for attitudes; however given time, once the anticipation for wind farms dulls, real problems may be revealed. Thus it is crucial to implement good practice procedures during the public participation process, especially when national adoption rates of wind energy are low. Early implementation of an effective public participation process system will ensure that when major problems do arise in future projects, experience and institutional processes would have had ample opportunity to evolve appropriately over a period of time. The double bounded Contingent Valuation Method was used to value the impact of the wind farm on the Waainek scenery through a hypothetical scenario based procedure which presented pictures of the landscape before and after the wind farm had been installed. Based on the perceived impact of the wind farm, respondents were asked their Willingness to Pay to relocate the development, based solely on visual impacts. Learning design Contingent Valuation (Bateman et al., 2008) is a novel technique employed to familiarize respondents with the hypothetical market institution as well as the scenic goods being valued. Average Willingness to Pay was found to be R67 per month, with a final total monthly negative visual impact of R104,000 to R121,000 per month for the entire Grahamstown community. Grahamstown Central (middle-high income) residents were more likely to pay than Grahamstown East (low-middle income) East residents because of socio-economic differences present in each area. A ranking exercise determined that while negative visual impacts are present, the overall benefits derived from the wind farm are potentially much higher. Additionally, positive scenic improvements were found, but were not measured due to time constraints, and would have worked to reduce the net visual impact of the Waainek Wind Farm. ¹Problem where individuals support the general concept of wind power, but when it comes to local implementation, opposition to the development arises within the same group.

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33

Dibennardo, Maurizio. "Performance based contracting: A concept for cost-effective operation and maintenance of wind power plants." Thesis, Högskolan på Gotland, Institutionen för kultur, energi och miljö, 2011. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-217024.

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34

Mohseni, Mansour. "Enhanced control of DFIG-based wind power plants to comply with the international grid codes." Thesis, Curtin University, 2011. http://hdl.handle.net/20.500.11937/1878.

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A review of the latest international grid codes shows that large wind power plants are stipulated to not only ride-through various fault conditions, but also exhibit adequate active and reactive power responses during the fault period in order to support the network stability. In particular, modern grid codes require wind power plants to: (1) ride-through various voltage sag and swell conditions, (2) inject reactive current into the grid during the fault period, and (3) attain swift active power restoration after the fault clearance. This thesis proposes a transient control scheme for DFIG-based wind power plants to comply with these requirements.In the first part of this thesis, the latest regulations enforced on large wind power plants are studied and compared. This study identifies the most stringent regulations defined by the international grid codes, to be further investigated in the following chapters. In the second part of this thesis, extensive simulation studies are carried out to examine the transient response of DFIG-based wind turbines under various symmetrical and asymmetrical fault conditions. Supplementary theoretical analyses are also presented to justify the observations made in the time-domain simulations results. For the first time, the impacts of phase-angle jump, voltage recovery process and sag parameters on the DFIG response are explored. The results of this study can assist researcher to identify the difficulties that hinder successful fault ride-through response of DFIG-based wind turbines, as requested by the international grid codes.In the third part of the thesis, an enhanced hysteresis-based current regulator (referred to as VBHCR) is proposed to be implemented in the rotor-side and grid-side converters of DFIG-based wind turbines. The main advantages of this current regulator are very fast transient response, simple control structure and insensitivity to the machine parameters variations. Simulation results show that on one hand the VBHCR has very good steady-state performance and on the other hand, it presents very fast/robust tracking response. Therefore, the DFIG equipped the proposed current regulator can fulfill the most stringent low-voltage ride-through requirements imposed by the international grid codes, i.e., those stipulated by the Australian grid code. In the fourth part of the thesis, a new hybrid current control scheme is introduced to enhance both low and high voltage ride-through capabilities of DFIG-based wind turbines. The proposed control scheme uses the standard PI current regulators under steady-state conditions but upon a voltage sag or swell occurrence, the supervisory control unit transfers the switching strategy of the rotor-side and grid-side converters to the hysteresis-based method. The VBHCR remains in action until the oscillation in the rotor current and dc-link voltage of DFIG suppress below the safety limit and then, the PI current regulator are activated through a re-initialization process.Finally, the conventional vector control scheme of DFIG-based wind power plants is modified to fulfill the regulations imposed on the active and reactive power responses of wind farms subject to various faults. New design strategies are suggested and their corresponding P-Q capability curves are thoroughly studied. Simulations results show that the proposed control scheme can meet the Australian regulations as the most demanding grid code. The best design strategy, with enhanced active and reactive power responses, permits the rotor-side and grid-side converters of DFIG to be temporarily overloaded during the fault period and also exploits the free capacity of the GSC to inject further reactive power to the grid. As a result, the active power generation of DFIG-based wind power plant can be retained during the fault period while its reactive power injection capacity of DFIG is also increased to further support the grid.

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35

Menzies, Greig Hamilton. "An economic evaluation of a wind power electricity generating farm in South Africa." Thesis, Nelson Mandela Metropolitan University, 2011. http://hdl.handle.net/10019.1/18156.

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Thesis (MComm (Economics)--Nelson Mandela Metropolitan University, 2011.
ENGLISH ABSTRACT: Renewable energy technology has received much attention over recent years. The depletion of known fossil fuel reserves and the volatility of international fuel prices require that society looks beyond the current coal-dominated electricity generation methods. Wind energy is an internationally well-established technology with large markets in major countries around the world, such as the USA and Germany. South Africa has the potential to generate large amounts of electricity from the wind because of the strength of the country’s wind resource. The long coast line and open areas are ideal for the exploitation of wind energy.
Sponsored by the Centre for Renewable and Sustainable Energy Studies

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36

Engström, Staffan. "Wind Farms Influence on Stability in an area with High Concentration of Hydropower Plants." Thesis, Uppsala universitet, Institutionen för fysik och astronomi, 2011. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-158447.

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The number of large-scale wind farms integrated to the power system in Sweden is increasing. Two generator concepts that are widely used are Doubly-Fed Induction Generators (DFIG) and Full Power Converters (FPC). The study is of a quantitative character and the aim of the Master thesis is to compare DFIG-models with FPC-models integrated in an area with high concentration of hydropower. Then it is possible to examine how the dynamics in the power system change depending on the selection of technology (DFIG or FPC) when connecting a wind farm. The power system is simulated during a summer night, i.e., a low load is connected. The Master thesis covers stability analysis of the power system by using rotor angle stability that are split into small-signal stability and transient stability (time-domain simulations) and finally voltage stability to see how the hydropower generators react when varying the power production in the wind farm. The Master thesis concludes that independently of wind turbine technique, integration of a wind farm has slight impact on the stability in the power system compared to a power system without a wind farm, even though the load is low. Further, an integration of a wind farms affects the reactive power production in neighbouring hydropower plants. Finally, when increasing the size of the wind farm the neighbouring hydropower station consume less reactive power which can induce problem with the voltage stability.

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37

Ahnlund, Joakim. "Short-circuit Contributions from Fully-rated Converter Wind Turbines : Modeling and simulation of steady-state short-circuit contributions from FRC wind turbines in offshore wind power plants." Thesis, KTH, Elektriska energisystem, 2014. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-144846.

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In recent years there has been an increase in wind power plants installed out at sea. The generated power of wind turbine generators (WTGs) are collected through numerous subsea cables into a single hub, the offshore platform. Subsequently, this platform is interconnected with the onshore main grid through a further stretch of cable. In the event of a fault, a sudden increase in current, so called short-circuit current, will occur somewhere in the system. The short-circuit current will, depending on the duration and location of the fault, potentially harm the power system. In order to accurately determine the dimensions and rating of the equipment installed in the offshore wind power plant (OWPP), the magnitude of this current needs to be studied. Furthermore, depending on the country in which the OWPP is installed, the transmission system operator (TSO) might pose different low-voltage-ride-through (LVRT) requirements on the system. One such requirement is that the installed turbines should provide voltage regulation through injection of reactive current. A type of generator able to achieve this is a so-called fully-rated converter windturbine generator (FRC WTG). Through a power electronic interface, the reactive and active current components of the generator can be freely controlled. With a high level of reactive current injected during a fault in the OWPP, the short-circuit contribution from these FRC WTGs needs to be evaluated. In this master’s thesis, a method has been developed in order to determine the steady-state short-circuit contribution from multiple FRC WTGs. This methodology is based on an iterative algorithm, and has been implemented in the simulation tool PowerFactory. To evaluate the performance of the method, two case studies were performed. In order to improve simulation times, an already existing WTG aggregation model has been implemented to reduce the number of turbines in the test system. From the results, it is concluded that the method obtains the expected FRC WTG short-circuit currents with sufficient accuracy. Furthermore, the deviation from the expected results are evaluated using a numerical tool. This project was initiated and conducted at ABB in Västerås, Sweden.

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Dincer, Ali Ersin. "Investigation Of Waterhammer Problems In The Penstocks Of Pumped-storage Power Plants." Master's thesis, METU, 2013. http://etd.lib.metu.edu.tr/upload/12615452/index.pdf.

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Waterhammer is an undesirable event, caused by sudden flow changes in a confined pipe system. When it occurs, its consequences can be very costly and even sometimes deadly. In general, it may be encountered in the penstocks of hydropower plants, water transmission lines, water networks, etc. Therefore, the operation guidelines of the hydropower plants should be defined correctly. In this thesis, waterhammer problems in pumped storage hydropower plants are investigated. Time dependent flow conditions in the penstocks are studied by the help of computer software, HAMMER. The software solves nonlinear differential equations by using method of characteristics. Firstly, hydraulic transients for various operational cases are investigated using some scenarios. Then a surge tank, protective device for waterhammer, is added to the system and for the same operational cases, hydraulic transients are studied again. Finally, the results obtained from the operation of the system with and without surge tank are compared. Wind-hydro hybrid systems are also included in the study.

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39

Pietrangeli, Sven. "Comparison of fixed diameter and variable diameter wind turbines driving a permanent magnet hub motor." Thesis, Cape Peninsula University of Technology, 2012. http://hdl.handle.net/20.500.11838/1283.

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Thesis submitted in fulfilment of the requirements for the degree MAGISTER TECHNOLOGIAE: Mechanical Engineering in the FACULTY OF ENGINEERING at the CAPE PENINSULA UNIVERSITY OF TECHNOLOGY, 2012
The amount of power a horizontal axis wind turbine (HAWT) can produce is determined by two main factors, wind velocity and rotor swept area. Theory dictates that the power production of a horizontal wind turbine is related to the cube of wind velocity and the square of the turbine diameter (or radius). The power produced at any given time is thus dependent on of the wind velocity and the rotor swept area of the turbine. Wind is variable in availability and consistency. Very little can be done to effect the wind velocity passing through the turbine rotor area and its effect is minimal. Thus understandably if more power is required, from the same wind velocity, the rotor diameter must be increased. A variable length blade can adapt lengthwise to accommodate low wind velocities and similarly high wind velocities during extreme conditions, thus increasing the operational time and power production of the turbine. The work undertaken in this thesis is a comparative study between standard design, fixed length blades to that of a modified design, variable length blade. The project entailed the design and development of small diameter HAWT blades and experimental testing. The turbine blades were designed using applicable theory and manufactured from available materials. For the experiments, the turbine was mounted on a vehicle and driven at various speeds. Due to size limitations, no dynamic adaption was done during testing. The variable length design blade was obtained by cutting increments off. The results obtained from each test were compared at corresponding points and conditions. Final interpretation of results lead to the conclusion that by increasing or decreasing the turbine blade length the area of turbine energy capture can be adjusted to affect the amount of power produced. Additional benefits included, force reduction during extreme operating conditions, extended production period for the turbine and a mechanical start up method during low wind speeds. The financial feasibility did not form part of the scope of this thesis and the technical feasibility of the concept can be thoroughly addressed in future research.

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Al, Buflasa Hanan Mubarak. "Impact of high wind power penetration into power systems with reverse osmosis desalination plants, taking Kingdom of Bahrain as a case study." Thesis, Loughborough University, 2008. https://dspace.lboro.ac.uk/2134/36131.

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This study is based on the Bahraini government's interest in the construction of largescale renewable energy projects in Bahrain. This thesis investigates the impact of integrating a high penetration of wind power into Bahrain's power system. It includes wind and site assessment and a study of the correlation between wind power and power demand. The power system is analysed before and after wind integration covering different wind penetration levels. In order to mitigate against the possible impact of high levels of wind power, the operation of reverse osmosis stations is modelled as a means of providing additional grid balancing. The geographical distribution of wind speed (the wind atlas) for the kingdom of Bahrain is presented, based on measured data and on calculations undertaken using WAsp and Matlab. The data used were recorded by the Meteorological Directorate using a weather station at Bahrain International Airport. The data were taken on an hourly basis for a period of ten years. These data indicate an annual mean wind speed of 6.93 m/s at 60 m height and mean Weibull scale and shape parameters C and k of 7.80 m/s and 1.79 respectively. This suggests that the area has a good wind resource. The wind atlas shows that several locations in the less populated central and southern regions of the main island of the archipelago of Bahrain are potentially suitable for wind energy production.

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DeLucia, Dominic. "A Parametric Study on Power Variation for Model Wind Turbine Arrays." PDXScholar, 2013. http://pdxscholar.library.pdx.edu/open_access_etds/1120.

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This thesis presents the results of wind tunnel experiments performed for various model wind turbine arrays. The aim is to understand how siting affects power output. To optimize wind farm efficiency the experiments vary the parameters of the model wind turbines and the layout of the wind turbine array. The parameters include the alignment, height, spacing, and the rotational direction of the model wind turbines. These experiments employ mechanical torque sensors to simultaneously measure the torque and rotor angular velocity, which yields a direct measurement of the fluid mechanical power extracted by the turbine at multiple locations. For a 4 × 3 array, the power is calculated at the center turbine in each of the rows. Variations in wind farm efficiency ranging from 55% to 90% are observed between the 13 different layouts tested. Modifications to the layout of the wind turbine array clearly affects the power output of the wind turbines downstream. The results of such experiments highlight the importance of studying the relationship between wind farm layout and power output.

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Jarvis, Christina M. "An evaluation of the wildlife impacts of offshore wind development relative to fossil fuel power production." Access to citation, abstract and download form provided by ProQuest Information and Learning Company; downloadable PDF file 0.67 Mb., 123 p, 2006. http://gateway.proquest.com/openurl?url_ver=Z39.88-2004&res_dat=xri:pqdiss&rft_val_fmt=info:ofi/fmt:kev:mtx:dissertation&rft_dat=xri:pqdiss:1430770.

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Alexander, Karen. "Offshore power production and marine stakeholders : from understanding conflict to impact mitigation." Thesis, University of the Highlands and Islands, 2012. https://pure.uhi.ac.uk/portal/en/studentthesis/offshore-power-production-and-marine-stakeholders(92df071b-42b0-4d65-a4b4-798d4300169b).html.

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Little is known about the impact of marine renewable energy installations upon the marine environment and those who use it. Harnessing marine energy will involve the offshore siting of energy extraction devices and their associated infrastructure. This will alter the local environment and substantially modify use and access for a variety of marine stakeholders, potentially leading to conflict. Using the Ecosystem Approach (EA) as a conceptual framework, this thesis aimed to answer the question: What is the potential for conflict between the marine renewable energy industry and marine stakeholders, and how can this be mitigated? The research consisted of three components which used a variety of methods: i) stakeholder identification through a review of the literature and use of a novel interactive mapping method; ii) an investigation of the potential consequences for the priority stakeholder which used a mail survey and in-depth interviews; and iii) an exploration of potential mitigation which used ecosystem modelling. The stakeholder most likely to be affected by marine renewable energy device (MRED) deployment was the fishing industry. Potential consequences included: navigation and safety hazards, loss of access and alternative employment. Further exploration revealed that a loss of livelihood was the all-encompassing concern for fishers, and that skills shortages (transferable skills) may mean that should a loss of livelihood occur there may not be acceptable alternative employment. The modelling exercise indicated that it is not currently possible to definitively predict whether any opportunities which may be created by MRED installation will mitigate any negative effects, and that exclusion zones may actually decrease catches for most fleets. The findings of this study have implications for ‘conflict-free’ development of the marine renewable energy industry. To address this, several policy recommendations were offered as regards to operationalising the EA in terms of marine renewable energy.

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Jayam, Prabhakar Aditya. "Application of STATCOM for improved dynamic performance of wind farms in a power grid." Diss., Rolla, Mo. : Missouri University of Science and Technology, 2008. http://scholarsmine.mst.edu/thesis/pdf/Jayam_Prabhakar_09007dcc804f7428.pdf.

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Thesis (M.S.)--Missouri University of Science and Technology, 2008.
Vita. The entire thesis text is included in file. Title from title screen of thesis/dissertation PDF file (viewed May 12, 2008) Includes bibliographical references (p. 64-66).

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Duvvury, Rolan Shawn. "Potential negative effects of wind turbines on the ear." Thesis, Georgia Institute of Technology, 2011. http://hdl.handle.net/1853/44927.

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This thesis presents investigations on the potential negative effects of wind turbine noise on the human ear from a sound point source (i.e. wind farm). In Chapter 2, the tectorial membrane, which is a crucial gelatinous structural matrix located within the cochlea of the inner ear, is considered to have a similar constitutive stress-strain relationship to that of an elastomer (rubber) in tension. The tectorial membrane appears to stretch when subjected to constant heavy sound stimulation. The tectorial membrane is modeled as a simply-supported beam with an external load Pext applied at midspan. A virtual work approach is used to balance the external work at midspan Pextδz of the tectorial membrane with the internal strain energy from its hysteresis loops. These hysteresis loops quantify the amount of damage that the tectorial membrane undergoes due to an applied external loading. Normalized damage tables are presented at the end of the chapter to suggest safe distances away from the wind turbines to limit damage to the tectorial membrane. Chapter 3 considers a hypothetical autonomous village constructed in South Pretoria, South Africa. This village accommodates approximately 2000 people (~500 families) and receives electricity for hot water from a nearby 2.5 MW wind farm. The design process for the village is discussed from an architectural and design standpoint. The wind farm specifications, specifically the number of 2.5 MW wind turbines needed to provide electricity for hot water, are established. Results from Chapter 2 are used to suggest minimum safe distances between the wind farm and the autonomous village in the context of limiting damage to the tectorial membrane.

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Kuiler, Ian Radcliffe. "Condition monitoring of squirrel cage induction generators in wind turbines." Thesis, Cape Peninsula University of Technology, 2017. http://hdl.handle.net/20.500.11838/2530.

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Thesis (MTech (Electrical Engineering))--Cape Peninsula University of Technology, 2017.
Globally governments are faced with challenges in the energy sector which are exacerbated by uncertain financial markets and resource limitations. The over utilization of fossil fuels for electricity generation has had a profound impact on the climatic conditions on earth. Coal power stations release carbon dioxide (CO2) during the combustion process and studies show that concentrations have sharply risen in the atmosphere. Adverse environmental conditions like global warming exist as a result of high greenhouse gas (GHG) emissions in particular CO2. In 2015 Eskom constructed Sere Wind farm with a supply capability of 100 MW. Due to the lack of technical expertise and skills with regard to the new technology within Eskom, Siemens was offered a 5 year maintenance contract. Siemens also provides training on basic operation and maintenance (O&M) of the wind farm to Eskom staff. This excludes specialised training on Siemens Turbine Condition Monitoring (TCM) systems which is a critical part to develop optimum maintenance strategies. This shortage of specialised skills in the application of condition monitoring techniques within Eskom is a major concern. If the most cost effective maintenance strategies during the contract period are implemented, the long term plant health and design life of Sere wind farm will be reduced. There is a need to develop new condition monitoring techniques to complement or address the shortcomings of the existing systems. Developing these skills will increase the understanding of the technology and improve the operating and maintenance of Sere wind farm.

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Torres, Sibille Ana del Carmen. "Visual Impact Assessment of Human Interventions on the Landscape: The case of Wind Farms and Solar Power Plants." Doctoral thesis, Universitat Politècnica de València, 2011. http://hdl.handle.net/10251/9147.

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El incremento de intervenciones humanas sobre el paisaje ha dado paso a una creciente preocupación social por la degradación del mismo y cada vez más, su mantenimiento comienza a plantearse en nuestra sociedad como una prioridad. En las últimas décadas, la investigación sobre el paisaje ha crecido de manera exponencial, impulsada por la necesidad de cumplir con mandatos legales. A pesar de ello, todavía no existe una herramienta universal para la evaluación del impacto visual que pueda ser utilizada por diferentes tipos de usuarios dentro del ámbito de la investigación y la planificación paisajística. Por otra parte, las herramientas desarrolladas son a menudo demasiado complicadas o demasiado específicas para ser útiles en la práctica. El objetivo de este trabajo es por lo tanto, desarrollar herramientas fiables y de fácil aplicación para cuantificar el impacto visual de las intervenciones humanas en el paisaje, por medio de una metodología potencialmente generalizable. Se presta especial atención a los parques eólicos y a las huertas solares. Se presentan tres casos de estudio. Cada investigación tiene como objetivo avanzar desde los resultados de la anterior, como complemento de la metodología, con nuevas herramientas. En el primer estudio, se desarrolla un indicador para medir la magnitud objetiva del impacto visual de los parques eólicos. El indicador combina medidas tangibles de visibilidad, color, fractalidad y continuidad que se puede tomar a partir de fotografías. Se construyen funciones de valor para cada variable y se incorporan al indicador. Este indicador se utilizó para calcular el impacto estético de cinco parques eólicos reales. La comparación estadística de los resultados del indicador con los obtenidos por consulta a una muestra de individuos, muestra que el indicador representa correctamente el orden de impacto según la percepción de la muestra de la población, por lo que es una medida objetiva y adecuada de los efectos visuales de los parques
Torres Sibille, ADC. (2010). Visual Impact Assessment of Human Interventions on the Landscape: The case of Wind Farms and Solar Power Plants [Tesis doctoral no publicada]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/9147
Palancia

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Suryana, Rahmat [Verfasser]. "Optimal Operation of Wind Power Plants with Doubly-fed Induction Generators under Considerations to Network Operator Regulations / Rahmat Suryana." Aachen : Shaker, 2017. http://d-nb.info/1138177636/34.

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Münsterberg, Torsten [Verfasser], and Carlos [Akademischer Betreuer] Jahn. "Simulation-based evaluation of operation and maintenance logistics concepts for offshore wind power plants / Torsten Münsterberg ; Betreuer: Carlos Jahn." Hamburg : Universitätsbibliothek der Technischen Universität Hamburg-Harburg, 2017. http://d-nb.info/1130704556/34.

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Thapa, Ravi Chandra. "Damping Interarea Oscillations in Power Systems with DFIG." Thesis, North Dakota State University, 2011. https://hdl.handle.net/10365/29173.

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With rapid depletion of fossil fuels and increasing environmental concerns, the trend to capture renewable energy, especially through wind energy resources, is increasing. The doubly fed induction generator (DFIG) is the most widely used generator for wind energy conversion because of its various advantages over other types of generators. In a DFIG, the rotor is fed through back to back converters via slip rings. The converters enable the generation control. This control property can be used to support reliable operation of a grid network system. Interarea oscillation has been a major factor in limiting power transfers in interconnected power systems. Poorly damped modes can trigger oscillatory instability, potentially leading to cascading blackouts in such systems. We consider a two-area system where DFIG based wind generation is integrated with conventional synchronous generators. A simple controller is proposed for the DFIG to improve damping of interarca oscillations. To support the proposition, case studies are conducted in Matlab/Simulink. The effectiveness of the proposed controller is then analyzed by eigenvalue analysis and verified with time domain simulation results. The results show that a properly tuned controller can increase the damping of dominant oscillatory mode by nearly 5% while improving the area transfer by about 200 MW of wind power. The results further show that with the proposed control strategy, damping of dominant oscillatory mode increased by more than 10%.
North Dakota State University. Graduate School
North Dakota State University. Department of Electrical and Computer Engineering

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