Electrical insulation materials, as impregnants and insulating oils in electronic equipment such as transformers and capacitors, play a critical role in their operation. The following is a comprehensive analysis based on material types, performance advantages, application cases, and development trends:

I. Major Types of Electrical Insulation Materials
1. Insulating Varnishes
Solvent-based: These include polydiphenyl ether modified varnishes, polyesterimide varnishes, epoxy-modified polyester varnishes, and silicone varnishes.
Solvent-free: These primarily include six types, including epoxy resin, unsaturated polyester, and diphenyl ether resins, with heat resistance grades ranging from Y (90°C) to C (>240°C).

Polyimide Insulating Varnish: This offers excellent insulation, thermal stability, and chemical stability, and is widely used in electronic components, motors, transformers, and other applications.

2. Oil-Impregnated Paper Insulation
A composite insulating material consisting of fiber paper impregnated with insulating oil. The main components are a combination of mineral oil, synthetic ester oil, or vegetable oil and cellulose paper. Widely used in cables, capacitors, transformers, reactors, bushings, and other equipment.

II. Performance Advantages Analysis
1. Advantages of Insulating Varnish
Heat Resistance: Heat resistance grades range from Y (90°C) to C (>240°C), meeting the needs of diverse temperature environments.
Electrical Performance: Excellent electrical strength and dielectric properties.
Chemical Stability: Excellent resistance to chemical media and various chemical corrosion.
Process Adaptability: Adjustable parameters such as viscosity and gel time to accommodate various impregnation processes.

2. Advantages of Oil-Impregnated Paper Insulation
Synergistic Effect: The synergistic effect between oil and paper compensates for pore defects, significantly improving dielectric properties.
High Temperature Resistance: Basalt composite fiber paper enhances high temperature resistance and flame retardancy.
Long Life: Blended insulating oil (60% mineral oil + 40% vegetable oil) increases the lifespan of insulating paper to 1.91 times that of a mineral oil-based system.
High Temperature Resistance: DPE insulating paper combined with vegetable oil can achieve a temperature resistance of up to 140°C.

3. Advantages of Polyimide Insulating Varnish
Thermal Stability: Maintains stable performance in high-temperature environments
Mechanical Strength: Provides excellent mechanical protection
Electrical Insulation: Excellent insulation properties

III. Specific Applications in Transformers and Capacitors

1. Transformer Applications
Silicon Steel Sheet Insulation: Low iron loss, high magnetic induction, smooth surface, and excellent punching performance

Amorphous Alloy Core: Reduces no-load losses by 70-80% and no-load current by over 50% compared to conventional transformers

Insulating Paper Applications: Pure sulfate wood pulp paper, synthetic fiber paper, etc. are used for winding insulation

2. Capacitor Applications
Oil-Impregnated Paper Insulation: Used in high-voltage capacitors, providing excellent dielectric properties
Film Materials: Polypropylene film, etc. are used in low-voltage capacitors, offering high dielectric strength
Composite Insulation: A combination of various materials meets the requirements of different voltage levels

IV. Material Performance Comparison
Performance Indicators: Insulating Varnish, Oil-Impregnated Paper Insulation, Polyimide Insulating Varnish
Heat Resistance Grade: Y-C, Up to 140°C (Extremely High)
Electrical Strength: Excellent Excellent Excellent
Chemical Stability Good Average Excellent
Mechanical Strength Average Good Excellent
Process Adaptability High Medium Medium
Cost Medium-High Medium-High

V. Development Trends
High Performance: Develop materials with higher thermal resistance and improved electrical performance
Environmental Protection: Develop environmentally friendly insulation materials to reduce pollution
Combined Use: Combine multiple materials to achieve synergistic effects
Intelligent Use: Develop intelligent insulation materials with self-diagnostic capabilities
Electrical insulation materials are key components of electronic equipment, and their performance directly impacts their reliability and lifespan. With the advancement of power electronics technology, the requirements for insulation materials will continue to rise, and related research will continue to deepen.