Large Scale Dielectric Test of Transformer Oil with Uniform Field Electrodes

Results of 60-Hz breakdown tests of transformer oil obtained with 3-, 15-, and 30-cm-diameter brass, copper, and aluminum electrodes are analyzed. The influence of the electrode area as well as the influence of different electrode materials is shown. It is suggested that for evaluation purposes of transformer oil, the statistical occurrence of the minimum, mean, and maximum values should be applied instead of the test values obtained with American Society for Testing Materials (ASTM), British Standards (BS), or Verein Deutscher Elektrotechniker (VDE) tests.