Electrical insulation materials can be categorized based on various criteria such as physical state, thermal class, and voltage rating; materials within different categories exhibit distinct properties and are suited for different applications.
Classification by Physical State
Gaseous insulation materials
Common types: Air, nitrogen, sulfur hexafluoride (SF₆), etc.
Key characteristics: Serve dual functions of insulation and cooling; widely used in high-voltage equipment such as gas-insulated switchgear (GIS) and gas-insulated transformers.
Liquid insulation materials
Common types: Mineral insulating oils (transformer oil, switchgear oil), etc.
Key characteristics: Eliminate air gaps to enhance dielectric strength while improving heat dissipation; widely used in transformers and power cables.
Solid insulation materials
Organic: Insulating varnishes, insulating adhesives, insulating paper, plastics, rubber, etc.
Inorganic: Mica, glass, ceramics, etc.
Composite: e.g., SMC (Sheet Molding Compound) fiberglass composites, polyimide films, etc.; offer a combination of high mechanical strength and insulating performance.