Repository logo
 

Research Publications (Engineering and Built Environment)

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

Browse

Author: search.filters.author.Hamatwi, E.Has files: Yes

Search Results

Now showing 1 - 2 of 2
  • Thumbnail Image
    Item
    Control of multi-level voltage source converters integrating a wind turbine system into the grid
    (IEEE, 2016) Hamatwi, E.; Davidson, Innocent E.; Gitau, M.N.
    In recent years, wind energy has proven to be the most competitive and environmental friendliest renewable energy (RE) source for generating electricity. Wind farms are more likely to be located far from the load centres, and hence the generated power has to be transmitted over long distances. A high voltage direct current (HVDC) transmission system increases the transmission capacity, improves the system stability, and possesses lower transmission losses. Therefore, it is the preferred means for power delivery over long distances compared to the high voltage alternating current transmission system. In this paper, a 690V, 2MW wind turbine is modelled to be integrated into a 33kV AC grid via a 3-level Neutral-Point-Clamped Voltage Source Converter-based HVDC transmission system. Three control schemes were implemented: a pitch-angle controller, a controller applied to the generator-side converter, and a controller applied to the grid-side converter. The proposed wind energy conversion system and control schemes were implemented in MATLAB/SIMULINK and simulations were carried out to analyse the performance of the system.
  • Thumbnail Image
    Item
    Optimisation of a hybrid PV-diesel system for rural application : the case of Oluundje village, Namibia
    (University of Namibia, 2017) Hamatwi, E.; Nyirenda, C. N.; Davidson, Innocent Ewaen
    The absence of electricity in remote and rural areas is one of the major challenges faced by many poor and developing countries. Hybrid energy systems (HES) based on photovoltaics (PV) are considered to be an effective option to electrify remote and isolated areas, which are far from conventional grids. This is true for areas that receive high averages of solar radiation annually. This research investigation involves the modelling, simulation and optimization of a PV-Diesel hybrid system for Oluundje village in Namibia. A site survey was conducted in a form of questionnaires and interviews for the purpose of load forecasting and system modelling. HOMER software was used to design and model the proposed hybrid energy system. Costs of different components, hourly solar radiation, and rating parameters are inputs of the simulation program. Sensitivity analysis was carried out using Homer. The optimal PV-Diesel hybrid system and diesel-generator-only system were compared both technically and economically. Based on simulation results, it was found that electrifying a remote village using a PVdiesel hybrid system is more advantageous when compared to the diesel-generator-only system as it has lower operating costs and emissions. This system may be used as a preliminary design to guide in the planning and modelling of similar systems for other remote villages.