The Department of Electrical Engineering in fulfilment of the
requirements for the Magister Technologiae in Electrical
Engineering at the
Cape Peninsula University of Technology
November 2013 / Pole mounted transformers (PMT) in rural areas present an opportunity for local
utilities to do current monitoring on these systems. These transformers are exposed to
abnormal amounts of stress due to the vast power demand in these areas. The aim of
this study is to develop a more cost-effective condition monitoring system. Transformer
current monitoring can be a dangerous practice if not done by suitably trained utility
electricians. Hence this study is partly aimed at the elimination of hazardous working
environments associated with manual electrical measurements.
An investigation to determine a safe and cost-effective way to obtain the electrical
measurements required from PMTs is undertaken. Although current measurements can
be done with a current clamp-on meter, these measurements still take place at the
phases of the transformer and are unsafe. The possibility of implementing wireless data
gathering on current clamp-on meters is therefore investigated. This is made possible by
a wireless sensor node (WSN) which gathers information and transmits it wirelessly to
a WSN base station.
This wireless solution is battery powered, necessitating battery replacements, therefore
leading to the investigation of magnetic fields, magnetic materials and magnetic
induction. A current clamp able to generate a high voltage (HV) output with minimal
magnetic field strength is developed. The magnetic fields produced by the transformer’s
phase cables are used to generate an alternating voltage. With the help of a
microcontroller and an energy harvesting circuit, this voltage is converted and used to
charge supercapacitors. The magnetic fields are also used to determine the current flow
in the transformer phase cables when the device is not in energy harvesting mode.
The device will then undergo comprehensive laboratory testing to determine its
accuracy and durability, and is then used to do ‘real life’ current measurements, the
results of which are compared against an off-the-shelf current monitoring device.
| Identifer | oai:union.ndltd.org:netd.ac.za/oai:union.ndltd.org:cput/oai:localhost:20.500.11838/1186 |
| Date | January 2013 |
| Creators | Zandberg, Hermanus Andries Jakobus |
| Publisher | Cape Peninsula University of Technology |
| Source Sets | South African National ETD Portal |
| Language | English |
| Detected Language | English |
| Type | Thesis |
| Rights | http://creativecommons.org/licenses/by-nc-sa/3.0/za/ |
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