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Theses and dissertations (Engineering and Built Environment)

Permanent URI for this collectionhttp://ir-dev.dut.ac.za/handle/10321/10

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    Modelling and performance analysis of doubly fed induction generator wind farm
    (2018) Aluko, Anuoluwapo Oluwatobiloba; Akindeji, Timothy Kayode; Dorrell, D.G.; Sewchurran, Sanjeeth
    Power generation from renewable sources like wind and sun have increased substantially owing to various challenges such as government regulations, environmental pollution and depletion of non-renewable energy sources over the past few decades. Of all renewable energy sources, wind appears to be the foremost of choice due to economies of scale. Due the intermittent nature of wind, the increase in the penetration of wind power to the grid gives rise to several challenges in which power quality is the most critical. The mitigation of power quality challenges to grid-connected wind energy systems and other renewable energy plants led to the development of the renewable energy grid code. This research focuses on voltage quality as one of the power quality issues affecting connection of renewable energy plants to the grid. This research models and performs analysis of a grid-connected doubly fed induction generator (DFIG) wind farm. Using the IEEE 9 bus system as a base case for the study, the modelled wind farm is then integrated into the base case. Steady state performance and performance during faults are analyzed using load flow study and transient stability studies respectively. The load flow study is carried out to comparatively evaluate the steady state stability of the base case and the wind farm integrated network with respect to the NRS 048 South Africa standard. The transient stability study is carried out on the wind farm integrated network with compliance to the South Africa renewable energy grid code (SAREGC) which allows the wind farm to reduce active power production during a continuous low voltage event below 85% at the point of common coupling. This work compensates the wind farm with a static synchronous compensator (STATCOM) to keep the voltage at the point of common coupling above the set point, thereby keeping the wind farm connected to the grid and supplying maximum active power during a low voltage event. The results show that the static synchronous compensator allows the wind farm ride through a low voltage event without disconnection and reduction in active power supply and the wind farm increases the transient stability of the network.
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    A design methodology for the supply of subterranean water through the use of wind energy
    (2005) Marais, Brett Richard
    The Reconstruction and Development Programme adopted by the Government of National Unity is more than a list of the services required to improve the quality of life of the majority of South Africans. It is not just a call for South Africans to unite to build a country free of poverty and misery; it is a programme designed to achieve this objective in an integrated and principled manner. Based on the strategic objectives, as highlighted in the White Paper on Water Supply and Sanitation Policy, with regard to alleviating the chronic potable water shortages in South Africa, this thesis investigates a design methodology to supply potable water through the use of wind energy. The design focuses on small rural off-grid developments where grid electricity either has not or will not reach, and where renewable energy is the only viable option. This thesis provides an overview of wind energy and presents the fundamentals of wind power calculations. It also formulates an overview of the historic and present situation with regards to potable water supply, and reflects on the need for urgent intervention. The feasibility of using wind energy to supply potable water to rural communities in South Africa is explored in a case study. The various problem areas are identified and examined and a wide range of possible solutions are recommended. A final flow chart for the system design is proposed, thus ensuring comprehensive design methodology from which future design of similar systems can be based.