What scenarios should different high-voltage circuit breakers be used in
Applicable scenarios of different types of high-voltage Circuit Breakers
Typical voltage levels of circuit breaker types, main advantages, and applicable scenarios
Oil immersed circuit breakers
ranging from 10kV to 200kV (traditional large substations) have a sturdy structure, impact resistance, and relatively low cost. They require high currents (several kiloamperes) and high mechanical strength requirements for old substations;
- Special places with low fire prevention requirements such as fuel and chemical industries;
- As the main protection device for power plants and transformer outgoing lines (still used in some 10 kV to 66 kV systems)
Low oil (low oil) circuit breakers
ranging from 10kV to 35kV are small in size, light in weight, and easy to maintain. They are compact switchgear for medium voltage distribution networks and urban distribution stations;
- Industrial parks with strict restrictions on land area;
- In situations where rapid maintenance is required
Compressed air circuit breakers
ranging from 30 kV to 220 kV use high-voltage air jet arc extinguishing, with a relatively simple structure.
- Outdoor switch stations for medium and high voltage transmission lines;
- Environmentally friendly, oil-free, and SF free environments;
- Specific projects that need to be matched with compressed air stations
SF gas insulated circuit breaker
110 kV -765kV (also used for 36 kV -220 kV GIS) has high dielectric insulation strength, small volume, and good arc extinguishing performance, suitable for Gis Switchgear in dense cities or indoor GIS areas;
- Main circuit breakers for ultra-high voltage (≥ 220 kV) transmission lines;
- Connection between generator set and power grid (generator circuit breaker)
≤ 35 kV (commonly 10 kV, 20 kV, 35 kV) have compact structure, long service life, low maintenance cost, and no gas leakage.
- Main circuit breakers for medium voltage (≤ 35 kV) distribution networks and substations;
- Industrial power distribution systems that require high reliability and rapid recovery;
- Vacuum module in GIS (applicable for voltages below 35 kV)
Hybrid/composite circuit breakers
(such as vacuum+SF, magnetic blow, etc.) are critical transmission lines that require high reliability and voltage in the 35 kV to 220 kV range, balancing the gas free advantage of vacuum and the high-voltage arc extinguishing capability of SF;
- Special projects that require high current interruption in a limited space
Generator specific circuit breakers
ranging from 10kV to 35kV (usually 10kV) have a compact structure and are designed specifically for the generator end to withstand high short-circuit currents. They are critical nodes within the power plant that connect the generator to transformers or busbars;
- Generator protection scenarios that require rapid tripping and low impact
HVDC circuit breaker (DC circuit breaker)
70 kV -500 kV (VSC-HVDC uses special arc extinguishing technology (such as gas, liquid or vacuum), which can achieve fast disconnection in DC systems
- high-capacity flexible DC transmission (VSC-HVDC) projects;
- Submarine or cross-border transmission projects that require reliable disconnection on the DC converter side
Key points for scene matching
The voltage level is the primary basis for selection:
≤ 35 kV → mainly vacuum or low oil circuit breakers;
35 kV -110 kV → SF coexists with compressed air, depending on land occupation and environmental protection requirements;
≥ 110kV → SF ₆ (or GIS) is the mainstream due to its small size and strong insulation.
Land occupation and environmental restrictions:
Urban dense areas, underground or indoor distribution stations tend to use SF ₆ GIS or vacuum GIS;
Projects with strict requirements for environmental emissions, such as green energy parks, tend to prefer vacuum or compressed air.
Maintenance and lifespan:
Priority should be given to vacuuming in situations that require long-term low maintenance, such as high-voltage lines that are far away from maintenance personnel;
Traditional facilities or existing oil immersed equipment renovation projects can still continue to use oil immersed equipment.
Special requirements:
Generator sets, HVDC systems, etc. have extremely high requirements for breaking capacity and impact tolerance, and use generator specific circuit breakers and DC circuit breakers respectively.
Summary
Vacuum circuit breaker: suitable for medium voltage (≤ 35 kV) distribution networks GIS、 Scenarios with high requirements for reliability and low maintenance.
SF circuit breaker: suitable for high voltage and ultra-high voltage (≥ 110kV) transmission, urban GIS, and substations with limited land occupation.
Oil immersed/low oil circuit breakers: still used in some old or high current demand substations, especially in the 10 kV to 66 kV range.
Compressed air, hybrid, generator specific, and HVDC circuit breakers: correspond to specific voltage ranges, environmental requirements, generator protection, and specialized scenarios for DC transmission.
Based on the above matching principles, the most suitable type of high-voltage circuit breaker can be quickly located during the project design phase to achieve safe, economical, and reliable operation of the power system.