Method and device for drying large-scale power transformer

Abstract

The invention relates to a method for drying a large-scale power transformer, which is used for improving the drying effect and shortening the drying time of the large-scale power transformer. A vacuum tank, a heating tube array and a vacuum pump form a drying system. The temperature and the vacuum in the vacuum tank change according to the set curve through controlling the work state of the heating tube array and the vacuumizing speed of the vacuum pump. The large-scale power transformer in the vacuum tank is dried and the deep water in the large-scale power transformer is vaporized. The invention adopts an intermittent vacuumizing method to control the vacuum in the vacuum tank so that the temperature and the vacuum in the vacuum tank change according to the set curve, thus the vaporization of the deep water in the insulating layer can not be affected by the too rapid change of the vacuum, and the drying speed of the large-scale power transformer is accelerated. The invention can greatly shorten the drying time of the large-scale power transformer and obviously improve the drying effect of the large-scale power transformer and can meet the insulating requirement of the large-scale power transformer to the maximum extent.

Description

technical field [0001] The invention relates to a method for drying a coil or body of a large-scale power transformer by using a vacuum drying tank, which belongs to the technical field of transformers. Background technique [0002] The moisture in the transformer is mainly gathered in the insulating paper (board) and transformer oil, which will reduce the insulation resistance, increase the dielectric loss, and the partial discharge voltage and breakdown strength will also drop sharply with the increase of the water content in the insulation system. The moisture will affect the operation of the transformer. Safety poses a greater threat, and in serious cases, it will cause a discharge breakdown accident. In addition, moisture also directly participates in the chemical degradation reaction of polymer media such as oil and paper cellulose, which promotes the degradation and aging of these materials, thereby accelerating the reduction of the dielectric strength of the insulati...

AI Technical Summary

Problems solved by technology

[0003] High-voltage and large-capacity transformers have a thicker insulating layer. Traditional vacuum drying methods, such as electric heating vacuum drying, hot air circulation drying, etc., cannot precisely control the drying process, and the pressure in the vacuum tank drops from atmospheric pressure to high. The vacuuming time of the vacuum is very short, it is easy to shrink the hair cells on the surface of the insulating paper (board), and affect the evaporation of deep water, resulting in a long production cycle and incomplete drying, which is difficult to meet the insulation requirements of the transformer

Images