What are common goals of On-line Maintenance of Power Transformers ?
the operational (short-term) maintenance is oriented towards quick recovery of the operational reliability of the transformer. It usually starts after the detection of a not-permissible deviation from the main parameter(s) of the oil-insulation system, most often the drop of the dielelectric strenght of the oil The process primarily focuses on the restoration of the given parameter(s) within the limits required by IEC norm.
the life-extending maintenance is focused on the savings achieved by the prolongation of the life-time of the transformers under safe operational conditions. The long-term or even continuous maintenance process is started by the detection of the complex symptoms of the rapid aging of the oil-cellulose system. The process is primarily focused on the reduction of aging process in the cellulose insulants