The development of a methodology to compile an insulator pollution severity application map for South Africa

[摘要] ENGLISH ABSTRACT:The main objective of this research project was to develop a methodology which can beused to assist in developing an insulator pollution severity application map (INSMAP),more particularly for South Africa. The techniques must be able to assist in determiningpollution severity levels.At the inception of this project a phase one insulator pollution severity application mapwas available; this map was based on an existing corrosion map, climatic maps and dustgauge measurements. The phase one map was conservative and did not highlight localisedpollution. To confirm and possibly improve on this map, a phase two map was developed,which was based on feedback from Eskom field personnel via an electronic insulatorpollution questionnaire survey (based on IEC 60815 guidelines).Jhe questionnaire wasincorrectly completed in most cases due to a lack of understanding by field personnel ofenvironmental pollution and the impact on insulator performance. This resulted in anunrealistic map with exaggerated contamination levels.To confirm the findings of the phase one map, a phase three approach was followed, whichwas focused on an investigation into pollution measurement techniques andmethodologies. Based on the phase one map, a need was identified to confirm bymeasurements the impact of distance-to-coast. Also, the validity of installing a dust gaugeat 3 metres above ground level, while insulators are at a height of 8 to 40 meters, had to beinvestigated. Two pollution monitoring programmes were established: a distance-to-coastand height-above-ground environmental pollution study. Various test methods aredescribed with a complete testing procedure, descriptive equations and related pollutionseverity classifications for insulator pollution (DDG and ESDD) and corrosion (CLIMATand metal specimens).The distance-to-coast test results confirm the phase one map, while the height-abovegroundmeasurements justify the installation of dust gauges at 3 metres above ground level.Good correlations were found for the distance-to-coast study between insulator pollutionseverity and corrosion rates.From the height-above-ground study, a slight (insignificant) decrease in pollution levelswas found for increase in height for insulator pollution and corrosion tests.Recommendations are made on setting up a basic pollution monitoring station.Key words: Insulator pollution, Corrosion, Distance, Height.

[发布机构] Stellenbosch University