The repair method and its organization in each case are justified by the scientific organization of labor, which ensures the highest productivity and high quality of transformers produced from repair. During individual repairs of large transformers under operating conditions, the entire range of repair work is carried out on almost one repair site, rarely on two.
The Right repairs
Repairs with opening transformers without disassembling the active part sometimes have to be carried out in temporarily constructed rooms, and in exceptional cases even outdoors, under the portal, using truck cranes, electric winches and other lifting devices. A visit to http://www.surplec.com/en/ will help you out.
Overhauls, when it is necessary to disassemble the active part, rewind or replace windings and insulation, disassemble the magnetic system, are carried out only in enclosed spaces equipped with lifting devices, while repairs are organized so that it is as close as possible to factory (industrial) conditions. However, rewinding and manufacturing of windings of the main insulation, re-insulation of the plates of the magnetic system, repair of bushings with voltage of 110 kV and higher, in this case, is also carried out in specialized workshops.
The Fine Repairs
Repair under operating conditions is carried out by field teams of electric fitters of repair enterprises. The beginning of individual repairs under operating conditions is preceded by a large organizational and preparatory work. Prior to the output of the transformer for repair, a statement of the scope of work is made up, it contains a list and scope of repair work and serves as a source document for determining labor costs, repair time, necessary technological equipment, spare parts, devices and materials. In the process of disassembling the transformer, the defective list and the amount of work included in the repair are specified. Using these documents, for the individual repair of high-power transformers, they develop a project for the organization of work (POR). Along with organizational and technical issues, it reflects the need for labor and material resources, issues of preparation for repairs, labor protection and safety measures, and contain a repair schedule.
The room selected for individual repair should be protected from dust and atmospheric precipitation, have lifting mechanisms or allow their suspension. The room must contain the transformer tank, its active part, racks for dismantled parts and details, a bench, oil cleaning equipment, materials, fixtures, scaffolding, stairs, etc. The room must be equipped with an electrical panel with electric power supply, have lighting, ventilation, and comply with all fire and sanitary requirements.
Particular importance is attached to lifting mechanisms and structures. They should ensure the safety of work and facilitate labor-intensive operations. Lifting mechanisms (electric hoist, overhead crane, hoist) must be mounted and checked before the start of repair, and if their test period has expired, they should be tested in accordance with labor safety requirements. The load capacity of mechanisms, slings, cables is selected depending on the weight of the transformer, which is indicated on its plate and in the technical passport.