Study on Thermal Aging Characteristics of Epoxy Resin in Saturable Reactor

The saturable reactor is widely applied for safe operation of the thyristor, and its failure will endanger the whole converter valve. The epoxy resin insulation of the saturable reactor endures a long-term thermal stress, which may make its insulation performance degraded rapidly. Therefore, in order to study the insulation deterioration of epoxy resins under thermal accumulation, accelerated thermal aging test was carried out. The results show that the mass loss rate of epoxy resin increases with aging temperature and time rising, and simultaneously, its thermal stability decreases slightly. The dielectric properties of the epoxy resin are tested in a wide frequency range from 0.01 Hz to 1 MHz. The results show that the dielectric loss tanδ of epoxy resin drops firstly and then increases with the ageing time and temperature. Finally, the FTIR results indicate that thermal aging causes the volatilization of phenol converted from benzene ring in the epoxy resin, which is the main reason for mass reduction.