Theses and Dissertations (Power Engineering)
Permanent URI for this collection
Browse
Recent Submissions
Item Modelling of transmission line faults using machine learning methods(Vaal University of Technology, 2023-03-30) Makgai, Maphale Lucas; Sutherland, G., Dr.; Joubert, A., Prof.Electrical transmission lines are a link between the generation station and the consumer. Any abnormality in transmission lines may result in a prolonged total electricity shutdown if not detected and identified accurately. Malfunctioning of transmission lines contributes to economic destruction and leads to wildfires and damage to electrical equipment. The existing literature has confirmed that 70 to 80 percent of the abnormalities that usually occur in transmission lines are single line-to-ground (L-G) faults. Detecting and identifying such faults will minimise restoration time. Machine learning-based models' accuracy has never been comprehensively tested in detecting and identifying L-G faults in transmission lines under noisy conditions. This study tested a MATLAB machine learning-based model to detect and identify L-G faults when introducing noise on these transmission lines.Item Development of a multi-protocol equipment interface for use in renewable energy systems(Vaal University of Technology, 2023-01-31) Benson, M; Sutherland, G., Dr.; Joubert, A., Dr.Modern renewable energy systems be it off-grid, grid-connected, hybrid or a combination consisting of different equipment allowing data communication through different wired and wireless methods. The combination of equipment by different manufacturers has an impact on the communication and functionality of these energy systems. The aim of the research is to develop a multi-protocol equipment interface allowing communication between different renewable energy equipment using different communication mediums and communication protocols. The communication protocols to be focused on were Modbus and SunSpec using RS-232, RS-485 and Ethernet as wired communication mediums between the equipment interface and renewable energy devices. The research methodology utilized allowed for multiple cycles to develop the equipment interface. The first cycle focused on the hardware design and the second cycle focused on the design and development of the software algorithm required to retrieve the data from various renewable energy equipment. The equipment interface has shown that it was able to obtain a single data register value using Modbus and SunSpec and that it can gather data values from multiple registers as required by the user for Modbus and SunSpec. The user has to specify communication medium and the registers which are required along with the data types and scale factors depending on communication protocol used.Item A testing and verification protocol for a modern bus bar transfer scheme based on the transfer philosophy and theory of voltage decay(Vaal University of Technology, 2020-04) Van Rooyen, Johannes Petrus; Le Roux, B. J.; Walker, J. J., Prof.This dissertation focuses on the creation of a testing protocol or procedure for verification of a modern motor bus bar transfer scheme. There are four main transfer methods addressed during this study and with it the main parameters affecting the operation of such a system. The complete construction of the simulation and training panel is described and with it the outline of the testing protocol for using this panel is given. Some simulation work was done to calculate the correct verification times based on mathematical formulation to lay out the criteria for verification of transfer methods when testing with a modern three phase test bench. On completion of result documentation, a detailed analysis is conducted to generate the testing protocol which is also discussed in detail. From the test results obtained it was possible to accurately test the 4 common transfer methods using the theory of voltage decay as a guideline, but the protocol will have to be adjusted to suit individual transfer system needs as each transfer system may be unique in design and function although the basic principles outlined during this report will stay the same. Possible steps to take when adjusting the protocol were addressed and some future work for testing motor bus bar transfer schemes was suggested.Item Partial discharge evaluation of a high voltage transformer(2015-02) Kyere, Isaac Kwabena; Walker, J. J.; Le Roux, B. J.This dissertation is devoted to the study of partial discharge evaluation of a high voltage transformer. The 400 V/300 000 V (300 kV) high voltage transformer in the high voltage laboratory was manufactured in 1967. Given the old age of the transformer and the crucial importance of insulation systems, it is vital to assess the condition of its insulation to ensure the effectiveness and the reliability of the transformer as well as the safety of the personnel using it. In order to achieve that, it is important to evaluate the partial discharge in the insulation system as this is the main cause of destruction of insulation. The phase-resolved partial discharge method was the main method used to perform the partial discharge measurements in this research. Partial discharge measurements were performed on a faulty 11 kV voltage transformer. Defects were also created in samples of solid insulation at predetermined locations with different shapes and sizes. The measurements taken on the 11 kV voltage transformer and samples of solid insulation formed a basis to prove the validity of the assessment methods on the 300 kV transformer. Using the method mentioned above, partial discharges were recorded with respect to the phase of the applied voltage with the aid of a commercial instrument which complies with IEC 60270, (ICM monitor - partial discharge detector from Power Diagnostix Systems GmbH). The observations from this study have furthered the understanding of partial discharge processes. The patterns recorded were analysed in order to conclude about the condition of the transformer. From the partial discharge pattern, the type and location of partial discharges were concluded. The patterns obtained from the transformer reveal that the device is healthy and can be operated up to 200 kV.Item Design and development of a high efficiency modulated Class E amplifier(2006-01) Crafford, Crafford, Hendrik Lambert Helberg Hendrik Lambert Helberg; Pienaar, H. C. v Z.Amplitude modulation is not commonly associated with effective amplifying. This work focuses on implementing amplitude modulation into a high efficiency Class E amplifier. Different types of amplifiers are compared with each other, to show the advantages of using a Class E amplifier. The theory of the Class E amplifier is dealt with in detail. A harmonic filter is designed for the amplifier to make it radio spectrum friendly. The modulation process is implemented with the aid of a transformer into the Class E amplifier. The advantage of this is that the transformer serves both as a radio frequency choke for the Class E circuit as well as a modulator. The implementation of the amplitude modulation into the high efficient Class E circuit was successful. The final Class E circuit had superb efficiency, the harmonic filter showed good harmonic attenuation and the modulation process had low distortion. All this resulted in a fine low power AM transmitter.Item Incandescent light power efficiency: an impact study on the power consumption of the Vaal University of Technology's light sources(2013-12) Adeniyi, A. O.; Sutherland, G.; Nicolae, D. V.; Joubert, T.In view of the energy consumption problems, an impact study, extensive laboratory tests and an investigation towards comparable energy saving light sources was carried out on the light sources identified in the survey conducted at the Vaal University of Technology (VUT), Vanderbijlpark campus. Three types of identified incandescent light sources were purchased and extensively tested in order to obtain viable statistical data on the life span, luminance delivered per unit, power consumption and economic effect, as well as identifying relevant energy efficient light sources for replacement purposes. A suitable computerised maintenance program has been developed to be introduced to the VUT that currently does not have a lighting system maintenance program. The case study was located within the empirical-analytical paradigm, using quantitative data. The identified aims and goals place the empirical part of the study in the category of implementation evaluation research that provides an overview of a maintenance plan.