11kV Vacuum Circuit Breaker (VCB) Panels
Spark Engineering Technology Bangladesh manufactures 12kV & 36kV indoor metal-clad vacuum switchgear integrating world-renowned ABB (Italy) VD4 fixed or withdrawable vacuum circuit breakers.
In a vacuum interrupter, electric arc extinction takes place in a sealed ceramic vacuum chamber at natural current zero. Rapid metal vapor condensation restores dielectric strength within microseconds, ensuring completely restrike-free operation and eliminating all fire or oil explosion hazards.
Key VD4 VCB Engineering Features:
- Metal-clad, horizontally drawout, dust & vermin-proof enclosure.
- Ceramic interrupter bottles for superior electrical & mechanical endurance.
- Stored energy motor-charged spring closing mechanism with manual trip/close pushbuttons.
- Comprehensive mechanical and electrical interlocks preventing racking under load.
- High dielectric heat-shrinkable busbar sleeves and fire-retardant barriers.
Technical Parameters of VD4 Vacuum Circuit Breaker (12 kV Class)
| Specification Parameter | Engineering Rating | Testing / Compliance Standard |
|---|---|---|
| Rated Operating Voltage | Up to 12 kV (36kV option available) | IEC 62271-100 / BS / VDE |
| Insulation Level (Power Frequency) | 28 kV / 35 kV RMS (1 min withstand) | IEC 60060-1 |
| Impulse Voltage Withstand | 75 kVp / 95 kVp (1.2/50 μs lightning crest) | IEC 60071 |
| Rated Normal Current | 630 A, 1250 A, up to 2500 A | Continuous Full Load |
| Rated Short-Circuit Breaking (Isc) | Up to 44 kA RMS peak / 31.5 kA symmetrical | Duty Cycle: O - 0.3s - CO - 15s - CO |
| Rated Short-Time Withstand (3s) | Up to 44 kA RMS (3 seconds duration) | High Thermal Capacity |
| Breaker Operating Time | Opening: 30–50 ms | Closing: 60–80 ms | Ultra-fast fault isolation |
| Mechanical Endurance | 30,000 Operations without maintenance | Class M2 Mechanical Duty |
11kV Load Break Switch (LBS) Panels
For distribution substations where a circuit breaker is not economically mandated, the FN12 Load Break Switch (LBS) offers high technical performance and cost-effectiveness. The salient feature of our LBS is its ability to permit normal load switching and disconnect safely even during prospective upstream disturbances.
Equipped with high-speed (snap action) make-and-break mechanisms and specialized arc chutes, the LBS is combined with HRC current-limiting fuses to clear short circuits in less than 10 milliseconds, preventing downstream transformer damage.
LBS System Highlights:
- Integrated earthing switch with interlocked access doors.
- Tripping mechanism actuated by fuse striker pins.
- Compact footprint ideal for package unit substations (USS).
- Complies with IEC 60265, VDE 0670, and BS standards.
Mandatory Interlocking & Operator Safety
Operator safety is central to our switchgear design. Every panel incorporates fail-safe interlocks to eliminate human error: