Leakage current data is utilised to investigate indicators of insulator surface degradation (ageing). An accelerated ageing test was developed to study the degradation of small samples of insulation materials (silicone rubber and EPDM). The computerised data acquisition system allows on-line capture of cycles of voltage and current every second. These data were then analysed to extract rms and mean values, FFT parameters and the instantaneous power absorbed during the test. The extracted data were then used as input to artificial intelligence software, based on the self-organising Kohonen maps, in order to identify trends in the surface ageing process. It was found that leakage current magnitude alone was not a suitable indicator of ageing but maps combining data input from multiple parameters did show some trends in the ageing process.
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