Application of AC Pulse Discharge Helium Ionization Detector to GC Determination of Dissolved Gases and Moisture in Transformer Oil

Performance of a self-made alternating current pulse discharge helium ionization detector (ACPDHID) and its application to the GC determination of dissolved gases and moisture in transformer oil were described.By discharging with a two-way AC pulse high voltage power source,anode sputtering and cathode contamination were avoided.Pure helium (purity 99.999%),without any additional purification,was used in the detection.The ACDHID was found to be working in good coordination with the temperature elevation programming and the bi-column switching system.Seven dissolved gases in transformer oil (i.e.H2,CO,CH4,CO2,C2H4,C2H6 and C2H2) as well as the moisture content were determined.Detection limits (3S/N) obtained for these gases were lower than 0.1×10-6μL·L-1.