High-voltage fuses are crucial electrical devices for overload and short-circuit protection in power systems. They can be categorized into multiple types based on structure, application, arc-extinguishing medium, and other criteria. The specific classifications and their characteristics are as follows:

I. Classification by Installation Location

Indoor High-Voltage Fuses

Model Identification: Usually starts with the letters RN (e.g., RN1, RN2).

Features: Compact size with a sealed structure, suitable for indoor power distribution equipment (such as switchgear cabinets, beside transformers) with voltage ratings ranging from 3kV to 35kV.

Typical Applications: Protect voltage transformers (RN2), power lines, and transformers (RN1).

Outdoor High-Voltage Fuses

Model Identification: Usually starts with the letters RW (e.g., RW3, RW10).

Features: Excellent weather resistance with rainproof and dustproof structures, suitable for outdoor power distribution lines (such as on utility poles) with voltage ratings from 3kV to 110kV.

Typical Applications: Protect outdoor transformers and overhead lines. Some models (e.g., RW11) are equipped with arc-extinguishing devices to achieve load breaking.

II. Classification by Arc-Extinguishing Medium

Solid Gas-Generating Fuses

Principle: When the fuse element melts, high temperature decomposes solid gas-generating materials (such as fibers, resins) to produce a large amount of gas, which blows and extinguishes the arc.

Representative Types: RN series indoor fuses, RW series outdoor fuses.

Features: Strong arc-extinguishing capability, simple structure, and low cost.

Oil-Immersed Fuses

Principle: The fuse element is immersed in insulating oil, which cools and extinguishes the arc when the fuse blows.

Representative Types: RW9, RW10 series (some models).

Features: Excellent arc-extinguishing effect, suitable for higher voltage levels, but requires regular oil quality inspection.

Vacuum Fuses

Principle: The fuse element is placed in a vacuum interrupter, where the high insulation of vacuum is used to extinguish the arc at an extremely fast speed.

Features: Strong arc-extinguishing capability, long service life, compact size. Suitable for high-voltage and large-current applications (such as urban power grids, substations) but with relatively high cost.

Sulfur Hexafluoride (SF₆) Fuses

Principle: Uses SF₆ gas as the arc-extinguishing medium, which serves both insulation and arc-extinguishing purposes.

Features: Outstanding arc-extinguishing performance, suitable for protecting high-voltage and large-capacity equipment, mostly used in GIS (Gas Insulated Switchgear) complete sets of devices.

III. Classification by Application

General Distribution Fuses

Applications: Protect conventional equipment such as power lines and distribution transformers, with moderate breaking capacity (e.g., RN1, RW3).

Special Fuses for Voltage Transformers (PT)

Applications: Specifically designed to protect voltage transformers, featuring small rated current (usually 0.5A) and fast arc-extinguishing speed to prevent the expansion of PT short-circuit faults (e.g., RN2, fuses matched with JDZ series).

Motor Protection Fuses

Applications: Protect high-voltage motors, capable of withstanding the inrush current during motor startup and having strong short-circuit current breaking capacity.

Capacitor Protection Fuses

Applications: Protect high-voltage shunt capacitor banks, need to withstand the inrush current from capacitor charging and discharging to avoid false tripping.

IV. Classification by Current-Limiting Characteristics

Current-Limiting Fuses

Features: The fuse element melts extremely quickly, extinguishing the arc before the short-circuit current reaches its peak. This limits the magnitude of the short-circuit current and prevents equipment from being damaged by large current impacts.

Representative Types: RN series, vacuum fuses, widely used for protecting important equipment (such as transformers, mutual inductors).

Non-Current-Limiting Fuses

Features: Long melting time, requiring the short-circuit current to reach its peak before the arc can be extinguished. The short-circuit current causes significant impact on the power system.

Representative Types: Some old-fashioned RW series outdoor fuses, mostly used for protecting non-critical distribution lines.