Fault diagnosis model of oil-immersed transformer based on Return Voltage Measurement

One of the methods currently being investigated as a possible non-intrusive diagnostic tool for condition monitoring of power transformer and cable is the Return Voltage Measurement (RVM), which will be improving the ability to detect the content of water concentration and the ageing process in the insulation system and can thus be an indicator of insulation quality and it´s ageing status. The polarization phenomenon was studied using RVM on oil-paper sample. In order to interpret its mechanism, the extended Debye model was introduced. With different circuit parameters, various simulation results were gotten. Furthermore, with different speed ageing condition test sample, measurements are accomplished in Lab. On the basis of this experiment as well as theoretical analysis, correlations between polarizations and ageing were analyzed.