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Research Publications (Engineering and Built Environment)

Permanent URI for this collectionhttp://ir-dev.dut.ac.za/handle/10321/215

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Subject: search.filters.subject.Grid integration

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    Perspectives on impact of high penetration of renewable sources on LV networks
    (IEEE, 2020-08) Chidzonga, Richard F.; Nleya, Bakhe
    In most countries, electricity power grids have not undergone extensive modernization and/or liberalization. They are still predominantly vertically integrated i.e. designed and opera ted top (Generation)-down (Distri bution/loads). Increasing electricity demand and rising costs are ca using congestion and strain on power distribution networks cperartens. Fossil fuels are in decline and blamed for most negative environmental l and cUmadc imp acts on world economics and societal maleficence. Through out the world they are heightened impetuses to migrate to cleaner Renewable Energy (RE) sources and incorporate more intelligence in the utilization of energy. This has birthed the concept of smart grids with high participation of various clean energy sources . Hybrid renewable energy generation (HRE) systems are complementary technologies that have potential to mitigate climatic variability effects which are still a challenge with respect to dispatchability of RE resources. The emerging smart power grids are no longer unidirectional in terms of energy Row, but also allow users to inject energy back into the grids. The bi-directional now of energy has a significant positive impact on overall systems design and operation. This article provides an overview of the preliminary work that done to assess impact scenarios on power grids with increased penetration of RE. Simulation results show possible negative factors that may affect QoS parameters of typical LV power networks.
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    Modeling and control of voltage source converters for grid integration of a wind turbine system
    (IEEE, 2016) Hamatwi, E.; Davidson, Innocent E.; Gitau, M. N.; Adam, G. P.
    Wind energy is one of the most promising renewable energy sources for generating electricity due to its cost competitiveness when compared to the conventional energy sources (fossil fuels). Wind farms are usually located far from the loads for minimal disturbances and optimal power generation. High Voltage Direct Current (HVDC) transmission is the preferred bulk power transmission system over long distances due to the minimal transmission losses, low costs and reduced environmental impacts. In this research investigation, a 690V, 2MW wind turbine equipped with a PMSG is modelled to be integrated into a local 33kV AC grid via a 2-level VSC-based HVDC transmission system. Three control schemes are implemented on the proposed system: a blade-pitch-angle controller applied on the wind turbine model, a field-oriented rotor speed controller applied on the rectifier for maximum power extraction, and a vector-oriented direct-current-link voltage controller applied on the grid-side inverter to keep the DC-link voltage constant and to ensure unity power factor. The proposed subsystems are implemented in MATLAB/Simulink and simulations are carried out to analyze the overall system’s performance.