Large-scale oil-immersed transformer insulating end ring and its manufacturing process

Abstract

The invention discloses a large oil-immersed transformer insulated end ring and a manufacturing technology thereof. The large oil-immersed transformer insulated end ring comprises casein glue layers and a plurality of layers of paperboards, and every two adjacent layers of paperboards are glued via one of the casein glue layer. The manufacturing technology includes: A, utilizing a board shearing machine to shear needed large electrical insulating paperboards into regulated dimension so as to obtain semi-finished paperboards; B, evenly spraying distilled water on the surfaces of the semi-finished paperboards, guaranteeing the paperboards to have certain bending capability, utilizing a roller press to roll the paperboards into cylinders according to technical requirements; and C, selecting casein glue which is strong in permeability on the insulated paperboards to glue the layers of the paperboards according to a single-face gluing technique, tightening the layers of the paperboards via a binding strap, placing in a drying furnace to be subjected to drying and vacuum oil spraying, and finally disassembling the binding strap. The large oil-immersed transformer insulated end ring and the manufacturing technology thereof have the advantages of simple technology, convenience in operation, reliability in performance, and capability of effectively avoiding or greatly reducing of transformer partial discharge magnitude caused by closed air bubbles in insulating parts.

Description

technical field [0001] The invention belongs to the field of transformers, and relates to a large oil-immersed transformer insulating end ring and a manufacturing process thereof. Background technique [0002] In recent years, with the development of high-voltage and ultra-high-voltage power systems, the voltage level requirements for oil-immersed power transformers have also increased, and the power supply range of transformers has continued to expand; because transformers play the role of transforming voltage and transmitting electric energy in the entire power system The quality of the transformer directly determines the power supply reliability and operating life of the entire power system. For this reason, transformer users put forward higher requirements on the quality of transformers, especially the size of partial discharge of transformers. For example: GB1094.3-2003 standard stipulates that for ACSD (and / or ACLD) induced voltage with partial discharge Test, accordi...

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Problems solved by technology

The second is the irregular shape of the transformer insulation structure determined by the heat dissipation and insulation strength of the transformer winding

Third, the material quality of transformer insulating end rings, oil, etc. is prone to defects, such as moisture, pollution, metal particles, etc.

Fourth, the shape of the electrodes inside the transformer is irregular, and the control of the distribution of the electric field is not yet mature.

However, for the partial discharge caused by the air in the cavity enclosed by glue, it is a very complicated work to deal with. First, there are many factors affecting the uneven distribution of the electric field inside the transformer; second, because there are many insulating end rings in the transformer, Coupled with the fact that the air bubbles are inside the insulation, it is difficult to accurately determine which one it is; third, the transformer insulation needs to be repeatedly disassembled, assembled, dried, vacuum oiled, statically placed, and tested when replacing it, which not only wastes A large amount of manpower and material resources will affect the production cycle, delay the delivery date, and may even damage the parts where the insulation strength can meet the requirements, making the corresponding test items of the transformer fail, and eventually the entire component may be scrapped and redone

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