Extension of service life of oil transformers with long-term operation

Technical condition evaluation performed for the equipment of power stations and substations is associated with a high wear level of power supply infrastructure which influences the states and modes of equipment oper-ation. The levels of such mutual influence and its regular patterns can be determined only at the general evaluation of the state of a whole power supply facility. Selecting a rational system to repair power oil transformers at distribution substations implies a problem with multiple variables based on the concept of reliability, obsolescence, renewal and industrial diagnostics. The paper provides recommendations to organize repair in a comprehensive way based upon the Customer's individual observations over the change of equipment technical condition in the course of its operation and quantitative evaluation of the technical state of transformers on a total of diagnostic parameters.