This standard specifies the use of Gas chromatography, CG to determine the moisture content in the sealing oil for transformer oil, turbine oil and hydrogen-cooled generator sets during operation. The moisture determination of Miscellaneous oil can also be referred to. Methods After collecting oil samples, vaporization, separation and detection are carried out with special Gas Chromatograph, and finally the moisture content is calculated compared with the standard oil sample. The standard details the requirements of Gas Chromatograph, Detector configuration and selection of Chromatography Column to ensure the accuracy and reliability of the measurement results.