Insulation Materials The Rapid Development
Insulation material is one of the most important materials in the transformer, Insulation Materials its performance and quality directly affect the reliability of transformer operation and transformer life. In recent years, the transformer products used in new insulation materials after another.
With the rapid development of science and technology, Insulation Materials electrical appliances, transformers and other electrical equipment is increasingly widely used. The reliability and service life of the transformer is largely dependent on the insulation material it uses. Insulation materials are increasingly engaged in the design and manufacture of transformers.
Over the past two decades, Insulation Materials transformers insulation materials aspects of new products, new technologies, new theories continue to emerge and development, so that the transformer insulation materials and its application has formed a very important discipline.
Insulation material, also known as dielectric, is a high resistivity, Insulation Materials low conductivity of the material. Insulation material can be used to isolate live or different potential of the conductor, so that the current flow in a certain direction. In the transformer products, Insulation Materials insulation materials also play a cooling, cooling, support, fixed, arc, improve the potential gradient, moisture, mildew and protect the role of the conductor.
Transformer insulation material heat resistance grade refers to the insulation material in the transformer to allow the maximum temperature. If the correct use of insulating materials, Insulation Materials you can guarantee the material 20 years of service life. Otherwise it will be based on 8 ℃ law (A-class insulation temperature for each 8 ℃ rise, half life cycle, B-class insulation is 10 ℃, H level is 12 ℃. This law is known as heat aging 8 ℃ law) Service life. The heat resistance of the insulating material composed of the polymer is lower than that of the inorganic dielectric. Insulation Materials The properties of insulating materials are closely related to their molecular composition and molecular structure.
The concept of insulation resistance Insulation material resistance refers to the insulation material in the role of DC voltage, the pressure for a long time, and the line on the charging current and absorption current disappears, only the leakage current through the resistance value / generally specified as the voltage Plus a minute after the measured resistance value that is the insulation resistance value.Insulation Materials For high-voltage large-capacity transformers, the insulation resistance is specified for 10 minutes.
With the increase of temperature, Insulation Materials the resistivity decreases exponentially, because when the temperature increases, the molecular thermal motion increases, the average kinetic energy of the molecule increases, Insulation Materials the molecular kinetic energy can reach the activation energy, the ion is easy to transfer.
Moisture immersion in the dielectric, an increase of conductive ions, but also to promote the dissociation of impurities and polar molecules. So the insulation material decreases as the humidity increases, Insulation Materials especially the insulation paper or insulating paperboard insulation resistance decreases more.
The moisture content of the dielectric surface of the dielectric surface is very sensitive to the surface resistance of the ion crystal, Insulation Materials and the hydrophobic material of the ionic crystal is more attractive to the water than the cohesion of the water molecules. The continuous water layer on the surface reduces the surface resistance. So electrical equipment due to moisture caused by reduced insulation resistance, Insulation Materials resulting in leakage current is too large and damage the equipment.
The surface of the dielectric is contaminated by impurities, Insulation Materials and the adsorption of water will cause the surface resistivity to drop rapidly. Insulation resistance of the insulating material is one of the most sensitive parameters reflecting the amount of impurities in the material. In order to ensure the insulation level of the insulating material, the insulating material plant must strictly control the cleanliness of the production environment in the standard of insulating material. The method of measuring the volume resistivity of the insulating material is often used to measure the impurity content of the insulating material.
In the case of the electric field strength is not too high, the electric field strength on the ion transfer capacity and the impact on the resistivity is very small. When the electric field strength increases, Insulation Materials the ion migration ability increases with the electric field intensity, so that the resistivity decreases, when the electric field strength increases to the dielectric near breakdown, due to a large number of electrons migration, the resistivity index exponentially.