Insulator pollution monitoring device : development, calibration and field evaluation

Schwardt, Wilhelm Heinrich (2005-04)

Thesis (MScEng)--University of Stellenbosch, 2005.

Thesis

ENGLISH ABSTRACT: The calibration and field evaluation of an Insulator Pollution Monitoring Relay (IPMR) were the main aims of this research programme. A repeatable artificial wetting test method was developed after several modifications were made to the steam system, test chamber and the test routine. The IPMR was successfully calibrated with insulators that were artificially polluted according to the solid layer method. Linear and polynomial relationships were determined after curve-fitting techniques were performed on the results. The calibration showed that the IPMR is capable as a device relating the maximum conductivity during artificial wetting to the ESDD, a severity classification parameter. The IPMR was successfully used in a salt fog chamber to determine if the device is capable to evaluate the severity of an instantaneous pollution event. The IPMR was successfully installed at a natural pollution test site along the Cape west coast. The conductivity measurements with natural wetting showed good correlation to flashovers experienced. A rule of thumb, developed to indicate a possible risk of flashover, was based on observations made on the relationship between humidity and surface conductivity. The measured IPMR data was successfully applied to quantify the site severity according to the conductivity measurement with natural wetting. This calculated severity value could be used in the assessment of flashover probability of high voltage insulators.

AFRIKAANSE OPSOMMING: Die hoofdoel van die tesis was die kalibrasie en veldtoetse van 'n isolatorbesoedelingsmonitor (IPMR). 'n Herhaalbare nagebootste benatting-toetsmetode is ontwikkel na veranderings aan die stoomstelsel, toetsruimte en die toetsproses. Die IPMR is suksesvol gekalibreer met isolators wat besoedel was met 'n nagebootste besoedeling volgens die "solid layer method". Liniêre sowel as kwadratiese verwantskappe is ontwikkel na krommepassings op die resultate uitgevoer was. Die kalibrasie het gewys dat die IPMR in staat is om die maksimum geleidingsvermoë wat d.m.v. nagebootste benatting verkry is, met die ESDD, 'n besoedelingsklassifikasie, kan vergelyk. Die apparaat is ook suksesvol gebruik tydens soutmistoetse om te bepaal of dit in staat is om 'n skielike besoedelingsgebeurtenis te kan meet. Na die afhandeling van laboratorium werk is die apparaat by 'n natuurlike isolator besoedeling-toetsstasie langs die Kaapse weskus geïnstalleer. Die geleidingsvermoë metings met natuurlike benatting het goeie korrelasie getoon met isolator oorvonkings. 'n Skattingsmetode wat ontwikkel is om moontlike oorvonkings te voorspel, is gebaseer op waarnemings wat gemaak is van die humiditeit sowel as die oppervlakte geleidingsvermoë. Die IPMR se geleidingsvermoë metings met natuurlike benatting is aangewend om die besoedelingsgraad van die gebied te bepaal. Die bepaalde besoedelingsgraad kan verder gebruik word om die waarskynlikheid van die oorvonking van isolators vas te stel.

Please refer to this item in SUNScholar by using the following persistent URL: http://hdl.handle.net/10019.1/50372
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