Automatic system for thermal-imaging diagnostic (ASTID) for the substation electrical equipment is based on mass-produced thermal-imaging modules ASTROHN-TA. Designated software for control and early flaw growth detection performs a non-contact IR diagnosis of any equipment that comes in sight of the system. In case of hardware malfunction, the system detects flaws in its operation real-time (i.e without turning off or deactivating the equipment) in the context of application conditions. The monitoring is automatic and put into practice by built-in data-mining system for heat distribution analysis (thermoanalysis). Built-in thermoanalysis allows to monitor all of the equipment types as per individual algorithms that are correspond with equipment groups, according to RD 153-34.0-20.363-99 “Method for Infrared Inspection of Electrical Equipment and Overhead Lines”.