Solid Insulation Material Used in Transformers
The solid insulating material used in the transformer refers to an insulating material whose material itself is solid or chemically reacted and physically changed into a solid. There are many kinds of solid insulation materials for transformers, such as insulating paper, insulating paperboard, Nomex paper, sizing paper, electrical laminated wood, epoxy glass cloth board, low dielectric loss laminate, insulating varnish, insulating rubber, cotton tape, and fastening tape. Reticulated polyester tape and so on.
1. Insulating paper: The insulating paper described here refers to pure sulphate wood pulp paper, and other insulating papers include synthetic fiber paper (such as NOMEX paper), nitrile insulating paper (such as Denison paper), and the like.
2. Insulating crepe paper: It is made by wrinkling of electrical insulation paper. There are wrinkles along its lateral direction, and the wrinkles are pulled apart when stretched. Wrinkle paper with different elongation can be produced due to different wrinkle processing procedures. The thickness of the insulating paper is generally 0.05 mm to 0.12 mm, and the elongation is in the range of 5% to 200%. Insulated crepe paper is often used for the winding insulation of oil-immersed transformers, such as the windings.
3. Nomex paper: is a heat-resistant synthetic fiber paper produced by DuPont of the United States. Nomex is the trade name for this fiber paper. Nomex’s main ingredient is aromatic polyamide, which has good heat aging properties. It can be used at 220 °C for a long time and belongs to Class C insulation material.
4. Sizing paper: It can be divided into single-sided adhesive tape, double-sided adhesive tape and rhombic adhesive tape. The sizing type is made by coating a phenolic resin or an epoxy resin with a 0.07 mm wound paper, followed by baking and drying.
5. Metallized paper: used for floor and electrostatic screens. The bottom paper is 0.2 mm thick insulating paper, the thickness of the aluminum foil is 0.02 mm lead and the insulating screen is insulated.