With the increasingly widespread application of GIS equipment

type and number of GIS defects increases. Many defects can be reflected by thermal distribution. Based on the technology of infrared temperature measurement and thermal image analysis

two kinds of thermal defect mechanisms and manifestations for GIS equipment are introduced

the corresponding diagnosis basis is proposed

and by analyzing examples of the image features for internal and external heat defects

the reasons for defects are summed up

which provide effective reference for how to distinguish types and cause of the defects

thus providing technical support to improve the level of state detection and deepen condition-based maintenance work.