Insulating paper is generally a sheet-like material formed by plant fibers, mineral fibers, synthetic fibers, or a mixture thereof, deposited on a paper machine by water or other media. Insulation paper has high tear strength, low elongation, and good insulation, and is therefore widely used as an insulating material in motors, cables, capacitors, and transformers. It is also an insulating material for laminates, composites, and prepregs. The main constituent material.
In recent years, with the development of the electric power industry, modern power generation equipment and transmission equipment have developed toward high pressure and large capacity. With the rapid development of world science and technology, a variety of high-performance synthetic fibers have been developed and produced and applied to the paper industry, such as poly. Ester fiber paper, polyaramid fiber paper, polysulfone fiber paper, polyoxadiazole fiber paper, etc. have been successfully applied to electric equipment such as batteries, transformers, and capacitors. In particular, the application of aramid insulation paper is the most common and successful.
Due to the special use of insulating paper, it must have some characteristics different from other paper types, mainly including mechanical properties, electrical properties and thermal stability.
Insulation paper can be affected by various external forces during use. For example, insulating paper used in high-voltage large-capacity generators can withstand high mechanical stress due to high-speed rotation, starting and stopping, and sudden short-circuit. Therefore, higher mechanical performance is required. , Including tensile strength and elongation at break.
Thermal stability is an important indicator of insulating paper, and it is a major factor in the generation of low-voltage insulation aging, which determines its service life. Under normal operating conditions, the electric field strength has only a slight effect on the insulation aging process. Insulating paper used for a long time in a relatively high temperature environment will be brittle due to thermal aging, gradually losing its mechanical and electrical properties.
Insulation paper is widely used in electrical equipment, so it must meet certain electrical properties. The electrical properties of insulating paper refer to its polarization, conductance, dielectric loss, and breakdown characteristics that occur under the influence of an electric field.
The properties of insulating paper are interrelated and cannot be viewed separately. In the selection and development of materials, it is necessary to comprehensively balance the advantages and disadvantages of various materials. In addition, to produce insulating papers with good electrical properties, metal ions and other impurities and bubbles and moisture must be avoided in the production process, and the insulation paper should have high uniformity.