M.Ing. (Engineering Management) / Engineering design capabilities are highly specialised skills and are often begot through a number of years in a field of specialisation, the research’s aim is to establish how this engineering design capability can be brought into a an organisation through the International Technology Transfer (ITT) medium. In this paper a case study is presented whereby a South African State Owned Organisation (SOC) collaborated with an international company for the acquisition of a new technology, which in turn meant the acquisition of new know-how for the organisation. Despite the dynamics that inherently arise due to the Developed versus Developing Country dynamics it is imperative that the knowledge transfer (KT) initiatives are just as successful, however the difficulty is faced in actually measuring the effectiveness of the knowledge transfer processes. The local engineering industry is still growing and many more of these collaborations are still to be seen in the country, hence it makes it imperative from an engineering management perspective that the quality of the knowledge that can be salvaged from these collaborations is great value for money and is unquestionable. To not only prove the main drivers of the effectiveness of the transfer but to also highlight the areas for improvement a survey in the form of a questionnaire was issued out to the participants of the ITT within the local organisation. Based on literature on similar studies and from the survey results, it is clear that training and engineering human resource development in engineering designs of the technology being transferred is the most important method of ensuring maximum technology transfer. Moreover it was established from the survey results that most often than not this aspect of the transfer process, although ranked as important, is not structured strategically for the benefit of the transferee. Herein, a proposal is thus made as to the key interventions that may be adopted to close the gaps in the technological knowledge aspirations of the organisation.

No description available.

M.Ing. (Electrical Engineering) / Induction heating has been used in practice for many years. The main goal of this study is to investigate the use of a single-turn coil in a typical induction heater. The work starts off with a background study of elecrroheat and specifically high-frequency induction heating. Finite element simulations were conducted on different coil shapes and compared with each other. The converter. with control and driver circuits. used in the, experimental setup, as well as the experimental construction and results are described. The work is concluded with an evaluation of the project.

No description available.

Reactive power compensation, as generated by capacitors, has been used to mitigate the constraints of power transmission and improve the power transfer of the transmission system of the South African power utility, Eskom‟s 66/22kV Albany-Wesley transmission system. An investigation was carried out on a number of current compensation schemes, and their operations, by means of load flow analysis. Different capacitor qualities and technologies were applied to alter the transmission line characteristics that resulted in acceptable voltage regulation. This resulted in easing the load on the lines and transformers and hence reducing line losses. For long transmission lines, utilities need voltage support, as provided for by different voltage compensators, to keep the terminal voltage within standard voltage regulation, and meet the designed power demand. The approach to large and small scale compensation was tested and the outcomes revealed distinct patterns that were used to confirm the hypothesis and improve the transfer of power. The templating temperature and thermal perspective as used by Eskom on line design was discussed and used to design a new transmission line. Load flow solutions were also used to plan and design the optimised transmission system as well as to determine the specification and location of the compensating capacitor banks. Capacitor banks, as a source of reactive power, were used to model the compensation in this research. Electrical protection and faults associated with the capacitors banks were discussed, as prevention to total blackout or load shedding on the transmission line in case of established contingency. Long term investment plans, to meet future electricity demands, require substantial investment hence a financial survey was carried out. Finally this dissertation selects a viable solution to meet the electrical power demands and then recommends a way forward for the Eskom‟s 66/22kV Albany-Wesley line.

The use of electrical networks for telecommunications has a long history. It has been known since the beginning of the twentieth century [Ahola03]. The idea of using electrical networks for broadband communications arose in the 1990s [Hrasnica et al 04]. Recent and growing research interest has indicated that PowerLine Communications (PLC) is the threshold for achieving broadband delivery particularly in very dispersed and low teledensity areas. Currently, there are numerous PLC trials and commercial deployments underway inside and outside South Africa. Nevertheless, these PLC deployments are very isolated, done without clear methodology and performance remains bound to the physical layout of the electrical network. Because of that high bandwidth broadband PLC systems are prone to poor performance and this in turn limits the acceptance and deployment of this emerging alternative broadband technology. Though, PLC technical challenges are being addressed, there has been little analysis and research work that is focused on the “Development of Methodologies for Deploying and Implementing Local & Medium Area Broadband Power Line in Residential and Office Electric Grids” that would lead to broadband PLC being adopted and be of greater use to non-broadband communities of South Africa. PLC is a term describing several different systems using electrical grid distribution wires for simultaneous distribution of data by superimposing an analog signal [Hrasnica et al 04]. The research proposed and presented broadband PLC methodologies for typical medium voltage and local voltage PLC networks. These methodologieswere implemented and experimented with in configurations which closely mirrored residential and office settings through laboratory and multibuilding experiments using commercial 2nd Generation Mitsubishi Electric PLC technology. Research results presented not only serve to provide insight into broadband PLC but also how it handled broadband applications (communications), competed and compared with other technologies such as Ethernet LAN. In combination with networking communication theories, the research explored and analyzed the extent of PLC in providing broadband communication to residential and office electric grids at the University Fort Hare, Computer Science Department.

Intrabuilding power distribution circuits offer a number of unique advantages for local area networking. To enable the selection of proper error-control codes and protocols for reliable data communication services, error pattern statistics of intrabuilding power line channels are obtained. Also, error-causing disturbances are identified and their relationships to specific types of error patterns are determined. It is found that error occurrence is highly periodic, with periodicity being a function of the power line frequency which is nominally 60Hz in North America. Furthermore, results indicate that error pattern behaviour is relatively insensitive to communication carrier frequency and modulation schemes. Based on the measurement results, hybrid ARQ with bit-interleaving is suggested for reliable data transmission at high data rate (19,200bps). Burst error correcting codes can be used to reduce decoder cost and complexity with some sacrifices in performance. At lower data rates (1,200bps or below), effective error control can be accomplished more easily. Finally, the attenuation characteristics of a number of typical power line channels are presented. It is found that high frequency bypass can be used to improve signal transmission between different phases of the distribution transformer. / Applied Science, Faculty of / Electrical and Computer Engineering, Department of / Graduate

The propagation characteristics of lightning surges in compressed SF₆ gas insulated power substation was studied using an electromagnetic transients program. Numerical models were developed to represent the behaviour of different system components especially under lightning over-voltage conditions. The characteristics of lightning surge propagation in overhead multi-phase untransposed transmission lines was analysed first. Modal analysis, together with special rotation techniques to fit time domain solutions were then used to simulate the wave propagation in multi-phase untransposed line in an electromagnetic transients program. Non-linear voltage-dependent corona attenuation and distortion phenomena were also investigated. Available field test results could be duplicated to within 5%. The characteristics of lightning surge propagation in multi-phase single-core SF₆ cables was studied next. A program was developed to obtain the cable parameters for typical cable configurations. The amount of core current returning through its own sheath and through the earth were computed to illustrate the single phase cable representation for wave propagation in single core SF₆ cables. / Applied Science, Faculty of / Electrical and Computer Engineering, Department of / Graduate

The multi-resonant technique, a novel concept in dc/dc power conversion, is proposed. The essence of the multi-resonant power conversion is the effective utilization of the major parasitic reactive components of the power stage, including the leakage inductance of the power transformer, output capacitance of the power MOSFET, and junction capacitance of the rectifier. The multi-resonant operation is achieved by addition of a resonant switching network around the semiconductor switching devices. Zero-voltage-switched multi-resonant converters (ZVS-MRCs) are proposed for high-frequency power conversion applications. ZVS-MRCs use a resonant network with one resonant inductor and two resonant capacitors. The resonant inductor is in series with the leakage inductance of the power transformer. One of the resonant capacitors is effectively in parallel with the power MOSFET, while the other resonant capacitor is effectively in parallel with the rectifier. As a result of the arrangement of the multi-resonant network, the major parasitic reactances of the power stage are utilized in the circuit. In addition, all semiconductor devices operate with zero-voltage switching, which substantially reduces the switching losses and permits efficient operation in multi-megahertz range, with moderate transistor voltage stress and wide load range. A dc analysis is presented for the basic converter topologies: buck, boost, buck-boost, Cuk, Zeta, and SEPIC. The analysis is performed using a generalized multi-resonant switch concept. The forward ZVS-MRC topology is employed to develop a state-of-the-art, high-density, on-board dc/dc power converter. The converter operates with a nominal input of 50 V and an output of 5 V at 10 A. The nominal switching frequency is 2.7 MHz. The complete hybridized converter has a power density of 50 W/in³ and a nominal efficiency of 83%. The feasibility of increasing conversion efficiency at several megahertz by means of resonant synchronous rectification is investigated using circuit analysis with nonlinear-capacitance MOSFET and Schottky diode models. / Ph. D.

published_or_final_version / abstract / Electrical and Electronic Engineering / Doctoral / Doctor of Philosophy