Theses and dissertations (Engineering and Built Environment)
Permanent URI for this collectionhttp://ir-dev.dut.ac.za/handle/10321/10
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Item Secured Power Line Communication based network for advanced metering in Smart Grid(2018-07) Khumalo, Zephania Philani; Nleya, BakheA Smart Grid (SG) generally refers to a modernized power grid system that incorporates Infor mation and Communications Technologies (ICT) so that a two way communication between the grid system (utility) and power users ensures power supply efficiency and optimization to the users. In a way, an SG is an evolved version of legacy power grid systems that manages electricity de mand in a sustainable, reliable and economic manner, built on advanced infrastructure and tuned to facilitate the integration of all involved. The provisioning of duplex communication between the utility and itsusers (customers) allows key devicessuch as SMs to interact directly with the utility 's control center (CC). SGs are destined for provisioning a cleaner environmental sustainable and renewable energy for the future. Its successes mostly rely on advanced ICT design and architecture. It is imperative that it meets the future data transmission and design performance requirements in terms ofrobustness, reliability, and at the same time ensuring end-to-end data exchanges with min imal latencies and losses. The incorporation oflCT, however, results in security and access control challenges, as a result complex network arrangement may be exploited by hackers among other things, access private information and sensitive data, hence the necessity to address vulnerabilities of such systems. Typ ical consequences or repercussions of security and access control threats include energy theft by way of altering of SM data. At present, it is cost effective to implement the ICT related infrastruc ture on the currently unused power line spectrum (i.e. above 50Hz) hence in this work, Power Line Communication (PLC) is elected for provisioning this platform. As such, PLC implementation shall imply the digital communication in power lines concurrently with electrical power transmission and ensuring uninterruption of either of the services, as well as guaranteed efficiency. We address approaches to increasing the data rate of transmission and re duction of bit error rates. That will enhance the performance of PLC and redevelopment ofreliable JCT without additional cost to the existing infrastructure of electrical grids. We also address secu rity and access control by implementing Advanced Encryption Standard (AES) protocol to secure SG related data in our proposed security and access control framework. Results show that the sys tem has low computational requirements, minimal latency and as well ensures confidentiality and integrity. The simulation is run on a combined MATLAB/ OPNET platform.Item An energy efficiency evaluation of a bagasse gasification system for the South African sugar industry(2018) Nene, Sinqobile Wiseman; D'Almaine, George Frederick; Lazarus, Ian JosephAbstract The sugar industry in South Africa has been in existence for over a century. During this period, it has experienced different challenges both in production and market value, but recently; it is experiencing some difficulties in terms of relying solely on the sugar market. Recently, with South Africa undergoing energy-mix processes, the sugar industry has identified an opportunity for the utilization of this excess bagasse. The generation of excess electricity can then be exported into the national grid after all factory electrical requirements have been fulfilled. Several studies have been conducted to develop a system that would be more efficient than the current system which is the direct combustion of bagasse and coal in some factories. This research followed a case study approach. Two systems, direct bagasse combustion and bagasse gasification, were evaluated for their thermal efficiency and their impact on the operation of the sugar industry. According to the available data, bagasse gasification system is said to be at least 50% more efficient than the current direct combustion system. The gasification system utilizes a bagasse gasifier instead of a conventional direct combustion boiler. The gasifier is used to gasify bagasse into synthetic gas, also known as syngas. This gas can be used in gas turbines to generate electricity, and it can be integrated into an existing steam system as a source of steam for process operations. The system analysis showed bagasse gasification system thermal efficiency as 55% as compared to the direct bagasse combustion system thermal efficiency of 19.68%. The knowledge contribution of this study was that of a practical evaluation of the current direct bagasse combustion system and the theoretical evaluation of the bagasse gasification system with similar inputs to identify the benefit of the utilizing the bagasse gasification system.