The basin-type insulator is a core component of gas-insulated switchgears (GIS)

serving as insulation

support

and isolation. With the increasing application of GIS

the issue of GIS failures becomes prominent due to subsurface defects in basin-type insulators. Therefore

it is important to carry out the research on the nondestructive test and identification of subsurface defects in basin-type insulators. In this paper

the finite element simulation is used to establish an epoxy basin-type insulator model with various subsurface air cavities. The dynamic temperature distribution characteristics on the surface of basin-type insulators are calculated

revealing the conduction pattern of infrared thermal wave energy in the basin-type insulator model. A defect identification method based on the improved infrared thermal image and surface temperature distribution of the basin-type insulator model is proposed. The results show that

under the external thermal excitation

the difference of temperature distribution on the air defect area of basin-type insulators can be identifiable. The inhomogeneous temperature distribution on the surface of basin-type insulators is greatly influenced by the depth and diameter of the air defects. Moreover

it is found that the infrared thermography and surface temperature distribution are closely related with the subsurface defects. Based on the surface temperature variation of the air defect area of basin-type insulators

the effects of different defect parameters on the maximum temperature difference and the time to reach the maximum temperature difference are achieved. Thus

the maximum temperature difference evaluation model for the basin-type insulator is established

and the validity of the model is verified. This research provides the theoretical guidance for the application of the infrared thermal wave detection in basin-type insulator and subsequent field test.