Applied Study On Oil Chromatogram Faults Diagnosis Of Large Transformer For Pingliang Substation

This paper analyzes the meaning, the present status and developmental trend of transformer oil chromatogram faults diagnosis, as well as its implementation in Pingliang substation. According to the domestic and overseas oil chromatogram detecting systems provided at present, considering the factors and error sources which influence the results of conventional oil chromatogram analysis, it has successfully fulfilled on-line monitoring of six gas solved in transformer oil with characteristic of infiltrative film. Large number of data has indicated that this system is stable, credible and able to reflect the status of transformer operation. It can be used as warrant of condition maintenance. Based on great investigations and researches, it analyzes the effects of various on-site disturbances on on-line monitoring and diagnosis of transformer oil gas chromatogram. Theses disturbances include transformer complemented weld, transformer complemented oil, filtering oil by vacuum oil filtering machine, oil permeation into transformer in switching room, oil latent pump, oil floating relay, active mental materials, oil floating static discharge, calcium carbide stove workshop, overloading, water and new transformer. Some valuable conclusions have been drew to entirely, synthetically and accurately diagnose transformer inner defaults. For conventional oil chromatogram analysis and on-line oil chromatogram analysis, the effects of different sampling points on transformer oil chromatogram analysis have been discussed. Particularly, when choosing sampling point for on-line case, the way of oil circulation, operation status, transformer structure, oil floating distribution, faults location and its extent must be taken into account. It also fully states the characteristics of gas solved in oil and its relationship with content, faults extent, types of default under the circumstance of transformer inner default or abnormity. Because the most present means of faults diagnosis are on-line or off-line, the author puts forward the value determination principal of identifying parameter, studies the normal model of grey correlation analysis. One analysis method of grey correlation called area correlation method, is proposed and practice has indicated its efficiency to diagnose the type of transformer faults.