Determination of Partition Coefficients of Gases for Insulation Liquids - Results of a CIGRE WG Round Robin Test

This paper discusses partition coefficients, which are an integral part of dissolved gas analysis (DGA) especially when using the headspace method to extract gases from oil samples. With its recent study, Cigre joint working group JWG D1/A2.77 has addressed this issue, where both a method to determine the coefficients and difference in gas solubility between various insulation oils and liquids in respect to partition coefficients are evaluated. The first part of the study concerns an evaluation of the method to determine the coefficients. Several laboratories participated in a Round Robin Test (RRT), where each laboratory determined the coefficients for identical gas-in-oil samples using the same determination method. This was to verify its applicability and reproducibility. The results are evaluated statistically and compared to values given in IEC 60567 [1] commonly applied within the industry for all mineral oil samples.