South African medium voltage underground electrical networks consist mainly of cables of
paper insulated lead covered construction. This construction is still the standard used for most
utilities in South Africa. While the in-service performance history of these cables has been
excellent, global manufacture of this cable type is decreasing.
Internationally, the use of polymeric cables is increasing, resulting in the security of the supply
chain for paper cable becoming an increasingly important issue. The most widely used
polymeric construction is cross-linked polyethylene. Modern distribution switchgear, which is
increasingly used in South Africa, is designed for the newer polymeric technology as this
enables more compact construction and reduced equipment footprint. The reduced clearances
present installation and operational issues when using modern switchgear with paper insulated
cables.
Although a comprehensive literature review was conducted, not much academic work has been
done on the process of migrating from one cable platform to another. Manufacturer data,
academic reference sources, industry experts and software modelling tools are used to
demonstrate that the use of polymeric technology is viable for South African utilities.
This dissertation focuses on the difference between paper and polymeric technologies, and
explores the advantages and disadvantages of each. Integration issues are examined along with
the methods used to overcome the challenges of hybrid or mixed dielectric networks. Economic
comparisons between paper and polymeric cables with respect to purchase and operating costs
(including the cost of losses) as well as steady state, cyclic, distribution and emergency current
ratings are made.
The dissertation concludes that it makes economic and engineering sense for users of paper
cable in South Africa to change to polymeric technology, taking the recommendations given
into consideration in order to choose an optimised cable design and gain maximum benefit from
the change. / Thesis (M.Sc.Eng.)-University of KwaZulu-Natal, Durban, 2011.
| Identifer | oai:union.ndltd.org:netd.ac.za/oai:union.ndltd.org:ukzn/oai:http://researchspace.ukzn.ac.za:10413/8601 |
| Date | January 2011 |
| Creators | Ryan, Morgan. |
| Contributors | Ijumba, Nelson M. |
| Source Sets | South African National ETD Portal |
| Language | en_ZA |
| Detected Language | English |
| Type | Thesis |
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