Analytic System Studies On Dissolved Gasses Analysis Of Transformer Oil

Dissolved gasses analysis (DGA) is the predominant method for forecasting incipient fault test and its corresponding diagnosis of the electric oil-immersed equipment. Operational status of the electric oil-immersed equipment is evaluated by the concentration of the dissolved gases, the ratio between certain gases and changing rate of gases concentration, providing the effective basis of the equipment maintenance. The gas chromatography is worldwide accepted DGA method with high sensitivity and accuracy.This work studied the Headspace GC detecting the 11 dissolved gases in the insulating oils and developed the partial degasses in conjunction with mobile GC method to detect 7 fault gases in transformer oils.1. Basically, the DGA includes the oil-gas separation and chromatography analysis domestically. This traditional method required analyst with relative high proficiency operation skill and the analysis speed is limited by the time of the oil-gases separation. Under the premise of guaranteeing testing result accuracy, the limitation doesn't meet the requirement of a great deal of work in third part lab, so the assembly of the oil-gases separation and chromatography technology creates the DGA analysis with speediness and accuracy.This work established a GC method coupled with headspace (HS) to analyze 9 kinds of dissolved gases in insulating oils, including dioxide (CO2), methane (CH4), ethane (C2H4), acetylene (C2H2), hydrogen (H2), oxygen (O2), nitrogen (N2), carbon monoxide (CO) and ethane (C2H6). In the thesis, we introduced the principle of dissolved balance degasses, set up the samples pretreatment method, improved the two-columns-valve-switch GC system and optimized the HS and GC condition, and verified the method of linearity, repeatability, recovery and chemical measurement uncertainty evaluation. In addition, we developed a GC method to detect propylene(C3H6), propane (C3H8) and the above 9 gases simultaneously, which reduced the gap between home and abroad, and provided the technology way of the domestic transformer mineral oil DGA test.2. The operational status of high-capacity oil-immersed transformer relates to power grid safety running. The high price of the domestic on-line DGA GC analysis technology restricts the widely popularity in spite of well stability and reliability. Other on-line analysis technologies are difficult to mix the kinds of analyzed gases and the sensitivity demand of the gases measurement result.This article also established a partial degas method in conjunction with mobile GC instrument to research the testing method of 7 kinds of dissolved gases (carbon dioxide (CO2), methane (CH4), ethane (C2H4), acetylene (C2H2), hydrogen (H2), carbon monoxide (CO) and ethane(C2H6)). We introduced the principle of partial degasses, optimized the partial degases method, verified the method of linearity, repeatability, reproducibility and detection limit. This work provided an on-site fast test method of oil-immersed equipment under Chinese circumstance.