The larger the capacity of the large-scale steam turbine generator, the higher the voltage, and the higher the requirements for the main insulation of the stator bar. The major companies in the world manufacture generators with their own insulation systems. The main insulation of the stator bar is very thin, but the voltage resistance level is high. but very high. At the beginning of the 21st century, the manufacture of large-scale steam turbine generator stator bars will be able to be wrapped with mica tapes with good bonding strength and less rubber powder and manufactured by vacuum solvent-free impregnation (VPI). The difference between the peak and valley of power consumption in the power grid is very large, and the insulation of the stator and rotor windings of the generator is required to be verified by 10,000 cold and heat cycle tests. Air and hydrogen-cooled surface-cooled turbo-generators also require a substantial increase in the thermal conductivity of insulation, which requires improving the thermal conductivity of materials such as mica tapes and paints. After the 1980s, there have been new developments in the world of insulating materials and insulation technology. In particular, the development of basic technologies such as nanotechnology, interpenetrating network technology and fiber reinforcement technology is applied to the transformation or development of new insulation technologies. More than 10 years ago, nano-tech titanium dioxide, silicon dioxide, alumina, calcium carbonate, etc. were added to insulating materials abroad to improve the toughness, elongation and other properties of the material, while the traditional technology usually reduces the strength of the material while improving the strength. toughness and elongation.
my country has also vigorously developed nanotechnology in recent years. For example, adding 5% to 20% of nano-titanium dioxide or silicon dioxide to polyimide films can greatly improve the corona resistance of polyimide films. Adding 10% calcium carbonate to ester plastic can improve its heat resistance by about 10%. The price of nanomaterials has also gradually dropped, from tens of thousands of yuan per ton to several thousand yuan. In recent years, applied research on the modification of insulating materials using interpenetrating network technology is also developing. The interpenetrating network technology is to fully mix two or more polymers and then solidify. There is no chemical reaction between the polymers involved in the interpenetration, but cross-penetration and mechanical entanglement. This network is forced at the molecular level. Mutual solubility and synergy can effectively improve the dispersibility and interfacial affinity of the system, thereby improving the phase stability and realizing complementary properties, which is an effective method to improve the properties of polymer materials. At present, the interpenetrating network between polyacrylate, epoxy polyurethane, polystyrene, vinyl resin, j-member network and their different varieties has been applied.
In recent years, the bone-shaped (dumbbell-shaped) short fibers developed by insulating material workers using the reinforcement principle of animal long bones are very effective for the reinforcement of composite materials. The concept of fiber morphological design is introduced to solve the contradiction between the strength and toughness of composite materials through special-shaped fibers, and overcome the problem that short fibers are easily disassembled from the matrix when the interface bonding is short, which leads to the failure of composite materials. It has application prospects in laminates.

In recent years, a lot of research work has been done abroad on the co-curing reaction process of epoxy resin and hydrogen ester. It has been greatly improved and has been widely used in metallized film Factory the fields of electronics, electrical, aerospace, and may also be used in large generators in the future.
Experimental and practical research on stator windings using high thermal conductivity materials. When the generator is cooled by air, hydrogen or evaporative surface, the heat consumption of the stator winding copper needs to be dissipated to the iron core or the air duct cooling medium through the insulator. The thermal conductivity of the stator winding insulator has a direct influence on the maximum temperature rise of the stator winding. Thermal conductivity of the insulating layer.
The stator winding ends of the large-scale steam turbine generators are fixed, and a large cone ring formed by intertwining glass fibers with mechanical strength and thermal expansion coefficient that meets the design requirements, supports made of high-strength flame-retardant laminates without air gaps, and Various film and tape insulation products with high temperature resistance, good mechanical strength and electrical strength. In short, the improvement of insulation materials and insulation technology is an important aspect of the development of turbo-generators in the 21st century.