Thesis (M.Ing.)--University of Stellenbosch, 2000. / ENGLISH ABSTRACT: The application of cycloaliphatic epoxide (CE) insulation in the Republic of South
Africa is investigated within this thesis. There was a request from industry to evaluate
the product and indicate its suitability for application within the various geographic
and climatic zones typical of the RSA.
An extensive survey was conducted into the historic origins of the material, and the
experiences of international utilities applying the insulation medium in respect of
polluted conditions. The properties of the Automatic Pressure Gelation (APG) CE
insulator manufacturing process are discussed with reference to the manufacture of
glass and porcelain insulation, and typical areas for concern are discussed with
reference to insulators found to deviate from specification.
Typical insulators were obtained from the manufacturers and utilities associated with
the product, and were subjected to electrical, material and visual examination tests.
The electrical tests included AC wet and dry, lightning impulse, clean fog, salt fog,
mould release resiliency and the IEC 1109 voltage test. The material tests included the
identification of the epoxide systems in use in the RSA, ultraviolet radiation aging
simulation, water hydrolysis and salt deposit density tests.
The main findings are:
• CE insulation is sensitive to marine pollution and continuous-wetting pollution
types.
• The use of CE insulation is promoted in respect of inland and medium
industrial pollution types.
• Class B pin-type CE insulation is prone to partial discharge related failures.
• Surface roughening on the insulator surfaces leads to reduced AC wet
flashover voltages and increased pollution catch.
Additionally:
• A comprehensive aging hypothesis was developed detailing three independent
aging stages/modes applying to CE insulation.
• A hypothesis was developed for a new evaluation method for documenting
changes on insulator surfaces due to the action of aging mechanisms: The
Surface Area Index. / AFRIKAANSE OPSOMMING: Die aanwending van sikloalifatiese epoksied (SE) isolasie in die Republiek Van Suid
Afrika word in hierdie skripsie ondersoek. Hierdie ondersoek is geloods op versoek
van die elektrisiteitsbedryf om die toepaslike aanwending van die produk onder die
verskeie heersende streeksweersomstandighede binne die RSA te evalueer.
Breedvoerige navorsing is gedoen om die geskiedkundige oorsprong van die materiaal
vas te stel, sowel as om die prestasie daarvan as insulasiemiddel te boekstaaf. Daar is
veral gelet op die prestasie van die materiaal onder besoedelende omstandighede en
ondervinding wat opgedoen is deur intemasionale ondememings. Die eienskappe van
die automatiese drukjelvormings-vervaardigingsproses (APG) word behandel met
verwysing na die maak van glas en porselein insulators. Tipiese probleemareas word
bespreek van insulators wat afwyk van spesifikasie af.
Verteenwoordigende isolators is vanaf vervaardigers en ondememings verkry wat met
die produk bemoei is. Hulle is blootgestel aan elektriese, materiaal en visuele toetse.
Die elektriese toetse het die volgende behels: nat en droog wisselstroom, skoon
waterdamp, sout waterdamp en die IEe 1109 spanningstoets. Die effek van die verlies
van die anti-kleefmiddel (gebruik tydens die gietproses) as gevolg van veroudering is
ook in detail behandel. Die materiaaltoetse het ingesluit: die uitkenning van die
epoksied stelsels in gebruik in die RSA, gesimuleerde veroudering deur
ultravioletligbestraling, water hidroliese en soutlaag digtheids toetse.
Die hoofbevindings is:
• SE isolasie word bemvloed deur seelug besoedeling sowel as volgehoue
benatting. Die gebruik van SE isolasie word voorgestel vir binnelandse
gebruik sowel as in gebiede met mediumvlak nywerheidsbesoedeling.
• Klas B pen-tipe SE isolasie is geneig tot deelontladings wat dan tot faling lei.
• Oppervlakvergroffing lei tot In verminderde wisselstroom orvonksspanning
onder nat toestande sowel as verhoogde vangs van besoedeling.
Bykomend hiertoe is:
• 'n breedvoerige SE verouderingshipotese ontwikkel wat drie onafhanklike
stadia en modusse van die verouderingsproses uitgewys het.
• 'n hipotese ontwikkel vir In nuwe evaluasiemetode om die verandering in die
isolatoroppervlak as gevolg van veroudering te dokumenteer: Oppervlakte-
Area Indeks (SAl).
| Identifer | oai:union.ndltd.org:netd.ac.za/oai:union.ndltd.org:sun/oai:scholar.sun.ac.za:10019.1/51613 |
| Date | 12 1900 |
| Creators | Van der Merwe, Neil |
| Contributors | Holtzhausen, J. P., Vosloo, W. L., Stellenbosch University. Faculty of Engineering. Dept. of Electrical and Electronic Engineering. |
| Publisher | Stellenbosch : Stellenbosch University |
| Source Sets | South African National ETD Portal |
| Language | en_ZA |
| Detected Language | English |
| Type | Thesis |
| Format | 158 leaves : ill. |
| Rights | Stellenbosch University |
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