The safe and stable operation of converter transformer

as a key device of DC transmission system

is crucial. Due to the long cantilever structure

the dry-type valve-side bushing of the converter transformer has a high risk of cracking in high seismic intensity regions. Existing research has usually overlooked the factors including the nonlinear temperature-dependent characteristics of epoxy materials and thermal expansion coefficient mismatches among components

and seismic dynamic response of bushing under thermal-mechanical coupling remains unclear. Addressing these issues

we established a thermal-mechanical coupled finite element model for ±500 kV converter transformer dry-type valve-side bushings. The influence of whether the thermal field was considered or not on the seismic response was compared

and the response characteristics were investigated for different installation inclination and peak seismic acceleration. The results show that thermal field slightly affects the characteristic frequencies

acceleration responses

and displacement responses

but significantly affects the stress responses. Under the consideration of the thermal field

the safety factor of the bushing is seriously insufficient

and the stress of the core root exceeds the tensile strength of the epoxy material. Although increasing the installation inclination can slightly reduce the stress

it still does not satisfy the safety factor regulation. The increase in load current leads to an increase in bushing temperature and stress peaks;meanwhile

when the load current reaches 1 000 A

the stress peak increases significantly. For high-intensity seismic application

the impact of thermal field can not be neglected.