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Faculty of Engineering and Built Environment

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    High voltage transmission system planning for a southern African regional grid
    (2022-09-29) Ndlela, Nomihla Wandile; Davidson, Innocent Ewaen
    It is proposed to use highly complex power system controllers to integrate African power grids into super-grids capable of accepting high levels of renewable energy penetration while maintaining power quality, active and reactive power flow, voltage, and power system stability. The proposed super-grid is built with ultra-high voltage direct current (UHVDC) and flexible AC transmission systems (FACTS), as well as dedicated AC and DC interconnectors with intelligent system applications, to create a Smart Integrated African Super-Grid. DC interconnectors will divide the continent's power grid into five substantial asynchronous portions (regions). Asynchronous segments will restrict AC fault propagation across segments while permitting power interchange between various regions of the super-grid, with minimal difficulties for grid code unification or harmonization of regular design regimes across the continent, as each segment retains its autonomy. A Smart African Integrated Electrical Power System Super-Grid powered by these technologies is critical to Africa's long-term economic growth and development; it is built on the foundation of green energy and harnesses over 200GW untapped potential of Africa's clean renewable hydro-electric, solar-PV, and wind power as part of a vast energy mix comprised of conventional and alternating energy resources. The proposed Super-Grid will power Africa's emerging economy and serve its 1.3 billion people by facilitating electricity trading and power exchange between regional power pools and countries. This study focuses on the development of the Southern African Power Pool (SAPP), into a robust Southern Africa regional grid (SARG), and prospects for a Smart Integrated African Super Grid. The Southern African countries have the potential to have a reliable, sustainable, and efficient electrical power grid; thus, the use of renewable energy is strongly encouraged, as is upgrading the existing AC grid, including encouraging power interconnections to exchange power more specifically for long-distance transmission networks when transmitting bulk power using High Voltage Direct Current (HVDC) and installing suitable FACTS controllers to maximize power transfer. Thus, the modernization of the traditional Power Grid into a Smart Grid will enable two-way digital communication technology by providing utilities with real-time, precise data on electricity demand, power outages, and quality of supply. This study develops a load flow model for a robust Southern African Regional Grid, and introduces a number of power interconnections for power exchange in the Southern African Regional Grid, to increase grid reliability, and reduce electrical losses. This load flow analysis was carried out using DIgSILENT PowerFactory. Results obtained from varying the load and observing the generator and transmission lines for different scenarios, using HVDC, and HVDC transmission links with FACTS controllers, are discussed and presented. This study is valuable as we seek to enable all SAPP countries to interchange power more efficiently, especially those who lack access to electricity
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    Geographic information system as a vessel for conventional and alternative forms of zoning
    (2020-10-06) Kitching, Joseph; Musvoto, Godfrey Gombana
    Given the well-documented rates of global urbanisation and the fact that sub-Saharan Africa is set to urbanise at the highest rate during the next few decades, it is easy to understand that urban management systems will increasingly be under pressure to operate efficiently, effectively and transparently in order to circumvent potential economic, social and environmental disasters. A land-use management system is one of the management systems in urban areas aimed at ensuring health and safety, environmental quality, sustainability, social equity, and amenity, amongst others. Since the beginning of the twentieth-century, a key tool of planners wishing to accomplish this, has been zoning. Although zoning has been abused, and heavily criticised for that, the objectives of zoning systems around the world echo noble values such as promoting environments that are safe from flooding and fire hazards, that encourage harmonious communities and economic growth, that preserve agricultural land, and protect the natural environment. Conventional zoning, which was significantly shaped by the US Supreme court’s village of Euclid decision, focuses on the separation of incongruent land uses. There are also several other types of zoning such a flexible Euclidean zoning, performance- based zoning and even no zoning. Amongst the novel types are form-based codes, which stem from the New Urbanism paradigm. Form-based codes focus more on the public realm and the appearance of spaces and structures rather than the use of space. Practically and problematically, both conventional and alternative zoning schemes are currently comprised of a map and a separate text document. The map depicts the geographic dispersion of zones, typically related to properties or zoning districts. The text document contains regulations pertaining to the various zones, procedures and definitions. Alongside the inefficient separation of regulation and map, are the variations within single zones where specific, locally important, regulations apply to some properties within the zone. Geographic information systems (GIS) have been evolving since the mid-twentieth century and have gained serious traction with the advent of the microcomputer. Defined by many as a system that captures, collects, manages, analyses and presents geographic data and attributes, it is essentially a database linked to a geographic component, In the case of zoning, it currently comprises geographic properties linked to attributes describing the zoning. The rigid, surveyed, property boundaries make the vector or discrete objects model ideal for the representation of zoning. The raster model – the other half of the debate – is useful in representing images supporting the regulations. Given the need for more efficient systems, the pervasiveness of corruption and poor capacity in municipal systems, the omni-present abuse of power, the need for an informed citizenry and laws that are comprehensible, this study aims to see if GIS can be used to represent the regulations in conventional and alternative schemes. To establish this, six sample cities from around the world, more than twenty conventional zones in the eThekwini municipality and two zones from the Daufuskie form-based code were assessed to determine what types of regulations are common and whether they could be represented as either geographic norms or attributes to geographic features. This study found that GIS is able to represent all regulations in conventional schemes and most of the regulations in alternative zoning. It also found that some regulations are naturally inclined to spatial representation, others as attributes, and still others as scanned attachments or hyperlinks. This implies that there is no need for the separation of regulations from property and the confusion and potential misinterpretation that are associated with current practices.