A comparison of the performance of high-voltage insulator materials in a severely polluted coastal environment

[摘要] ENGLISH ABSTRACT: The main aim of this research programme was to compare the relativeperformance of different insulator materials used in South Africa when subjectedto a severe marine pollution environment. A test programme and procedure, testfacility and instrumentation were established. Some novel instrumentation andmonitoring equipment were developed and built specifically for this researchprogramme, supported by data analysing software programs. In order tocompare material performance only, all non-material design variables betweenthe test insulators had to be removed (e.g. creepage distance, connecting length,inter-shed spacing, profile, etc.). To achieve this some of the test insulators hadto be specially manufactured. Leakage current, electrical discharge activity,climatic and environmental data was collected successfully over a one-year testperiod, starting with new test insulators.The peak and energy values of the leakage current were identified as the twomain parameters needed to describe the leakage current activity on the testinsulators. A correlation was found between the climatic and environmental dataand the leakage current data, and it was found that the leakage current can bedetermined successfully from some of the climatic and environmental parametersmonitored by using multiple regression techniques. Surface conductivity andenergy were found to be the best parameters to show the maximum andcontinuous interaction of the insulator material surface with the electrolyticpollution layer. A natural ageing and pollution test procedure was developed,which has become a South African standard and is gaining internationalacceptance.A model and hypothesis are proposed to describe the electrical discharge activitythat takes place on the test insulators and explain the difference in leakagecurrent performance of the various materials.Keywords: Insulator, Pollution, High Voltage, Leakage current, Materialperformance.

[发布机构] Stellenbosch University