| In recent years, domestic investment and operation of large power transformers in order to achieve and GIS connectivity, high voltage transformer bushing widely used insulating oil-SF6 gas structure high-voltage capacitor bushing(referred to oil and gas bushing), compared with the traditional connection methods, the use of oil-SF6 bushingconnection has more benefits,such as high reliability, no corona noise pollution, less maintenance and other advantages. With this type of bushing used more and more widespread in recent years, oil-gas bushing fault condition occurs excessive capacitance happen in many plant, including State Grid, China Southern Power Grid and other power companies, if the capacitance of the core bushing discharge that an accident will be happen,such as bushing breakdown eventhought an explosion,that situation threatenthe security and stability of power system, so to carry out research of such issues is important.In this paper, the main Transformer 500 HC resin-impregnated paper oil-SF6 bushing of Guangzhou pumped storage power station, the following referred to as oil-gas bushing, which was manufactured by England Legend Corporation,. In the past years of operation, the capacitance of the bushing had been over standard for several times. Some other power station also ues this type oil-gas bushing, such as THP pumped storage powerstation,GuangdongShajiao C power station,Dachaoshan power station.Theproblem that capacitance of the bushing had been over standard has also happened in these power stations.In order to make clear the fault reason of this type oil-gas bushing,a fault oil-gas bushing,which had classic fault characteristic,was chosen to be studied in aspects of VFTO level simulation,test of insulation characteristics,analysis of anatomy,analysis of design method and electricfield simulation.The study on fault reason of the oil-gasbushing mainly included the following content.By combining the above analysis and research, the fault analysis and study on the main Transformer oil-gas bushing was carried out systematically and comprehensively so as to make clear of the fault reason of the bushing and give a suggestion for choosing oil-gas bushing. This paper studies the class main transformer high voltage bushing fault analysis and problem solving has good reference value and significance. |
