Indoor MV SF6 Circuit Breakers (Fixed / Withdrawable)

Property Specification

Type: Medium-Voltage Indoor SF6 Gas Circuit Breaker (Fixed and Withdrawable Configurations)

Features: Utilizing sulfur hexafluoride gas for both arc quenching and dielectric insulation, this medium-voltage breaker achieves smooth current interruption without arc chopping or overvoltage generation, substantially reducing electrical and thermal stress on network components. The breaker poles feature sealed-for-life pressure construction requiring zero routine maintenance. Driven by a stored-energy mechanical mechanism, it provides independent, trip-free opening and closing operations. Constructed on a lightweight yet rigid steel frame, the assembly is available in fixed execution or withdrawable versions fitted with an integral racking carriage for easy switchgear installation and removal.

Applications: Ideal for power distribution systems safeguarding power lines, transformers, distribution substations, heavy motors, and capacitor banks. Its overvoltage-free switching performance makes it well-suited for retrofitting, upgrading, or expanding aging infrastructure with insulation sensitive to dielectric stress.

Description

Transposed Technical Comparison Matrix

Performance Characteristic / Parameter Medium-Voltage SF6 Gas Circuit Breaker Technical Specifications
Maximum System Voltage (Ur) 12 kV – 17.5 kV – 24 kV – 36 kV – 40.5 kV
Power-Frequency Withstand Voltage (1-min dry)

12 kV: 28 kV | 17.5 kV: 38 kV | 24 kV: 50 kV

36 kV: 70 kV | 40.5 kV: 95 kV

Lightning Impulse Withstand Level (Up Peak)

12 kV: 75 kVp | 17.5 kV: 95 kVp | 24 kV: 125 kVp

36 kV: 170 kVp | 40.5 kV: 185 kVp

Continuous Load Current Capability (Ir)

12 kV / 24 kV: Up to 3600 A (fixed) / 3150 A (withdrawable)

17.5 kV / 36 kV / 40.5 kV: Up to 2500 A – 3150 A

Short-Circuit Interrupting Rating (Isc / 3 s)

12 kV / 17.5 kV: Up to 50 kA

24 kV: Up to 40 kA

36 kV / 40.5 kV: Up to 31.5 kA

Peak Making Current Capacity (Ip) 40 kAp to 125 kAp across line product range
Standard Operating Cycle O – 0.3s – CO – 15s – CO (standard) / O – 0.3s – CO – 3min – CO (high duty)
Switching Speed Characteristics

Opening Time: 35 ms – 60 ms (12–24 kV) / 45 ms (36–40.5 kV)

Arc Duration: 10 ms – 15 ms

Total Interruption Time: 45 ms – 75 ms

Closing Time: ≤ 85 ms

Insulating Gas Medium Pressure Absolute pressure 380 kPa to 550 kPa depending on interrupting capacity
Inter-Phase Distance Options 150 mm, 210 mm, 275 mm, or 350 mm center-to-center spacing
Thermal Operating Envelope -5°C to +40°C