HD 487 S1:1987

Determination of water in insulating liquids by automatic coulometric Karl Fischer titration

Scope

This standard describes a method for the determination of water in unused or used insulating liquids with coulometrically generated Karl Fischer reagent - The method is applicable to water concentrations of 2mg/kg to 100 mg/kg - The precision data given in Clause 10 apply only to new oils with viscosity less than 20 mm 2/s at 40° C (see note) - Appendix A contains two suitable methods for preparing the reagents which may be useful in countries where it is difficult to buy prepared reagents - This method should be supplementary to the classical Karl Fisher titration as described in IEC Publication 733: Determination for Water in Insulating Oils-impregnated Paper and Pressboard and, in case of dispute, this latter method shall be used as a reference for arbitration (Note: For liquids in service the accuracy of the method may be affected by the presence of contaminants and degradation products)