Abstract
M.Ing. (Engineering Management)
Electricity is a crucial key component in the everyday life influencing the economy, safety,
health, productivity and comfort of the people. Power utilities continue to make the continuity
of electricity supply to the consumers their first priority. Power transformers are the crucial part
of the power system network because they regulate the voltage either up or down on the
electrical network for safe use by the consumers. Their reliable operation on the network is very
critical because it directly impacts the reliability and stability of the entire electrical network
connected to it.
One of the major challenges power utilities face is the failure of substation power transformers
on the distribution network. Sudden failures of these transformers cause the interruption of
supply to the customers. For the utility, it causes high transformer repair costs and revenue loss.
The power utility is also forced to replace the failed power transformers in order to reduce the
outage time for the affected customers. Although power transformers have become the heart of
the distribution network, the success rate for these transformers to complete their full life cycle is
not a guarantee.
The performance of the power transformers on the Limpopo distribution network has not
reached the projected target set by the plant performance department in the past four years and
this is cause for great concern. There was a number of power transformer failures recorded in the
substations. After investigations were conducted, it was found that the major causes for these
failures were aging, overloading, improper maintenance schedule, internal faults and insufficient
security measures in substations in remote areas. This dissertation looks at the methodologies
that are currently being implemented to ensure that the installed substation power transformers
approach or complete their full life cycle. It further proposes the improvement of the
methodologies currently being implemented.
The conclusion reached in this study is that in order for the substation power transformer failures
on the Eskom distribution network in Limpopo to decrease, the methods that can alleviate the
problem include: installation of an online monitoring system on the power transformers;
improvement of the maintenance schedule; installation of a backup transformers in single
transformer substations; improvement of the security measures in substations that are located in
remote areas; putting asset replacement plans in place for transformers that are approaching their...