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). Its improving ability to detect the content of water concentration and the ageing process in the insulation system can be an indicator of insulation quality and it´s ageing status of the transformer. The polarization phenomenon was studied using RVM on oil-paper sample in the paper. In order to interpret its mechanism, the extended Debye model was introduced. Various simulation results were collected using different circuit parameters. Meanwhile, physical measurements with different speed ageing condition test samples were also accomplished. On the basis of this experiment as well as theoretical calculation, correlations between polarizations and ageing were analyzed.