Seismic evaluation and analysis of 1100-kVUHV porcelain transformer bushings

Abstract

Abstract Shaking table tests were carried out on five 1100-kV ultra-high voltage (UHV) porcelain transformer bushings to evaluate their seismic performance. Finite-element models of the bushings were established. The influence of different types of connection on the seismic responses of the oil-side bushings was analysed. A simplified method to rapidly estimate the seismic responses of transformer bushings was implemented. Test results indicated that the safety factors of the porcelain insulators met the seismic requirements of the relevant standards. However, the metal flange might have cracked in earthquakes. Increasing the rotational stiffness of the connection reduced the seismic responses of the oil-side bushings. The mode mass participating coefficients of the first mode of the UHV transformer bushings were between 0.6 and 0.65. The simplified method presented in this paper was able to estimate the seismic responses of the 1100-kV UHV transformer bushings, with results close to those of the shaking table tests.