Investigation on Hot Spot Temperature of Resin-Impregnated Paper High-Voltage Bushing Based Upon Dielectric Loss

The resin-impregnated paper high-voltage bushing (RHB) has explosion-proof and flame-retardant advantages compared with the oil-impregnated paper bushing. However, the RHB failure is frequently caused by high temperatures, so it is essential to investigate the hot spot temperature of the transformer RHB. Thus, the multiphysics field simulation model of the transformer RHB is developed. Furthermore, the hot spot temperature distribution pattern is obtained. In terms of the transformer RHB temperature rise test, the transformer RHB frequency-domain spectroscopy (FDS) is carried out under load and oil temperature variables. In addition, the relationships between the transformer RHB hot spot temperature and FDS curves are established. It is illustrated that the inversion method of the transformer RHB hot spot temperature is based on the dielectric loss tangent integral. According to the tan
$\delta $
curves, the dielectric loss tangent integral and the square of the dielectric loss tangent integral are used as the characteristic parameters for the inversion of the transformer RHB hot spot temperature. The results show that both characteristic parameters have a well-fitting exponential correlation with the transformer RHB hot spot temperature. In addition, this conclusion enables nondestructive measurement of the transformer RHB hot spot temperature to improve the thermal reliability of its operation.