Abstract
M.Phil. (Engineering Management)
In recent years, electricity supply has become the driving force behind economic growth in many cities, urban areas and businesses around the world. As a result, utilities are under pressure to supply reliable electricity to their customers at all times. Most power outages take place in the distribution network, and the most used distribution network in the city and urban areas is Medium Voltage (MV) underground cable distribution network is due to space constraint. The power disruption statistics in Europe and South Africa indicates that the rate of power outages is high in the MV network adding up to 80% of the entire electrical distribution network. However, the national regulator expects the City of Tshwane to manage these interruptions effectively and to improve network reliability.
This dissertation will begin by giving a detailed description of the City of Tshwane MV underground cable network. Thereafter, the research will identify, quantify and characterize factors that cause cable failures and poor reliability of this network. It is very important for the municipality to understand these causes before making any asset management decisions in the network since condition assessment or replacement of underground cables is very difficult and restoration times are long due to the complexity of cable access. The research also looked at the available solutions in various literatures that can benefit the municipality in terms of knowledge. Some of the solutions include different network configurations.
The research methodology used in this paper is a quantitative approach, which applies statistical analysis methods for failure prediction, and a qualitative method is also applied for in-depth explanation of the data. The focus of this research is a case study about the City of Tshwane municipality, using secondary data.
MV underground cable failure data evaluation was divided into four stages so that important network behaviour characteristics could be analysed. The first stage was MV network data and information acquisition. The second stage consisted of cable failure analysis, where equipment failure was the highest. The main cause of equipment failure is insulation failure. In the third stage, Pearson’s linear correlation method is used to evaluate the relationship between cable failure behaviour and various climatic seasons (temperature and rainfall). The findings were not...