The Program Design Of Data Detection And Malfunction Diagnosis Based On Gas Chromatography

1. IntroductionElectric transformer is not only the most important and most expensive equipment, but also one of the most accident-prone equipments in electric system. The running reliability of electric transformer can ensure directly the safe running of electric system. Oil is usually used to insulate and emit heats in the large electric transformer. Under the condition of running voltage, the transformer oil and the solid organic insulated material (paper and cardboard etc.) in the oil will decompose because of the multiplicate factors such as electrics, heats, oxidation and partial arc. It will be decomposed to produce a few low molecular hydrocarbons such as firedamp (CH₄), ethane (C₂H₆), ethene (C₂H₄), ethane (C₂H₂) and carbon monoxide (CO), carbon dioxide (CO₂), hydrogen (H₂). Most of the gases will be dissolved in the oil. The potential overheated and discharging electricity malfunction in the transformer will quicken the speed of gas producing. The decomposed gases in the oil form air bubble and increase continually because of the convection and pervasion. In a certain extent, the component and content of dissolved gases in transformer indicate the insulation aging and malfunction degree of transformer. In order to ensure safety and credibility of the transformer, it is important to detect the component, content and speed of gas producing in the oil of transformer, to find out the potential malfunction in the transformer. The portable gas chromatography detection system can find out the potential malfunction in the transformer as soon as possible and forecast the developing trend of malfunction. It is an important instrumentality to monitor the running of electric transformer and ensure its safe and economical running.Dissolved Gas Analysis (DGA) is one of the mainly technology methods to diagnose the internal malfunction in transformer. By request of DL/T722-2000, < Guide to the analysis and the diagnosis of gases dissolved in transformer oil >, the component of H₂, C₂H₂, C₂H₄, C₂H₆, CH₄, CO and CO₂ is used to judge and analyze the internal malfunction in transformer. Because the method of gas chromatography to analyze the dissolved gas component has the advantages such as high separation efficiency, rapid analysis speed, high detecting sensitivity etc. It is applied extensively in electric power department at home and abroad. Of late years, with the developments of chromatography analysis technology and software,...