The Smart Grid system being developed includes the automated intelligent system of the continuous computerized control and diagnostics of the electric equipment. It has the expanded set of sensors covering all units and systems of the object and enables early detection of the destructive processes. High wear-out rate of the high voltage transformers constitutes a hazard for the operating personnel and manufacturing process. The most essential task of the Smart Grid technology is to introduce instruments of monitoring and diagnostics into the energy systems and industrial electric networks. The authoring team is developing the intelligent system of the continuous computerized control and diagnostics of the power transformers. System modifications reflect transformers’ application (network, unit and furnace) and specific features of their modes. Propagation of the intelligent systems for diagnostic control ensures possibility of the real introduction of the Smart Grid technology into electric networks of the industrial enterprises.