1. Select the circuit breaker corresponding to the voltage level based on the power grid level
The standard voltage (12/24/40.5/72.5/126/170/245/363/420/550/800/1100kV) is matched with the corresponding nominal voltage of the power grid. For example, for a 35kV power grid, a 40.5kV circuit breaker is selected. According to standards such as GB/T 1984/IEC 62271-100, the rated voltage is ensured to be ≥ the maximum operating voltage of the power grid.
2. Applicable scenarios for non-standard customized voltage
Non standard customized voltage (11/22/44/52/132/230/275/300/345/400/380/765kV) is used for special power grids, such as the renovation of old power grids and specific industrial power scenarios. Due to the lack of suitable standard voltage, manufacturers need to customize according to power grid parameters, and after customization, insulation and arc extinguishing performance must be verified.
3. The consequences of selecting the wrong voltage level
Choosing a low voltage level can cause insulation breakdown, leading to SF leakage and equipment damage; Choosing a high voltage level significantly increases costs, increases operational difficulties, and may also result in performance mismatch issues.

1. Their core difference is arc-extinguishing media: Vacuum breakers use high vacuum (10⁻⁴~10⁻⁶Pa) for insulation and arc extinction; SF₆ breakers rely on SF₆ gas, which adsorbs electrons well to quench arcs.
2. In voltage adaptation: Vacuum breakers fit medium-low voltages (10kV, 35kV; some up to 110kV), rarely 220kV+. SF₆ breakers suit high-ultra high voltages (110kV~1000kV), mainstream for ultra-high voltage grids.
3. For performance: Vacuum breakers extinguish arcs fast (<10ms), have 63kA~125kA breaking capacity, suit frequent use (e.g., power distribution) with long life (>10,000 cycles). SF₆ breakers excel in stable large/inductive current breaking but work less frequently, needing insulation recovery time post-extinction.

1. The core differences between porcelain column circuit breakers and tank circuit breakers—two main structural types of high-voltage circuit breakers—lie in six key aspects.
2. Structurally, porcelain column types are supported by porcelain insulation pillars, with open-layout components like arc extinguishing chambers and operating mechanisms. Tank types use metal-sealed tanks to encapsulate and highly integrate all core parts.
3. For insulation, the former relies on porcelain pillars, air, or composite insulating materials; the latter combines SF₆ gas (or other insulating gases) with metal tanks.
4. Arc extinguishing chambers are mounted on the top or pillars of porcelain columns for the former, while built inside metal tanks for the latter.
5. In application, porcelain column types suit outdoor high-voltage distribution with a dispersed layout; tank types adapt flexibly to indoor/outdoor scenarios, especially space-constrained environments.
6. Maintenance-wise, the former’s exposed components enable targeted repairs; the latter’s sealed structure reduces overall maintenance frequency but requires full inspections for local faults.
7. Technically, porcelain column types offer intuitive structure and strong anti-pollution flashover performance, while tank types boast excellent sealing, high SF₆ insulation strength, and superior resistance to external interference.