Investigation for a reference material for the dynamic drop test (DDT) with a reproduceable and repeatable retention time

With the dynamic drop test method (DDT), the hydrophobicity retention of polymeric insulation materials can be evaluated under stress with droplet under electrical field stress, which results also to droplet corona stress. The CIGRE WG D1.58 carried out a round robin Test (RRT) with the aim of clarifying the reproducibility and repeatability of test results (hydrophobicity retention) with this method. In the participating laboratories, retention times were determined on the same insulating materials, which have both a very good agreement and considerable deviations from one another. Even with repeated tests in a laboratory, different retention times are sometimes measured for identical technical insulating materials, whereby the reason for this was not fully evaluated up to now.For this reason this investigation shows the research work based on evaluation of possible reference materials to check the repeatability and reproducibility of different test stands and different test locations.