Overview
The ZN12-12/40.5 indoor high-voltage AC vacuum circuit breaker is engineered for 12 to 40.5 kV three-phase AC 50 Hz power systems, delivering exceptional reliability, explosion-free operation, and minimal maintenance requirements. It is ideally suited for critical applications in power plants, substations, and industrial transmission networks where consistent switching performance and dependable fault interruption are paramount.
Built to comply with GB1984-89 standards, the ZN12 series integrates the actuator and breaker into a compact structure, featuring a spring energy storage operating mechanism. This design supports frequent switching operations, heavy load interruption, and long service life under demanding electrical conditions while maintaining mechanical stability and operational safety.
Model Designation
Construction
The ZN12 series features a compact, integrated actuator-breaker structure with a spring energy storage operating mechanism. This configuration ensures reliable performance during frequent switching cycles and enables robust interruption of heavy fault currents. The mechanical design emphasizes stability and durability, supporting extended service life even in electrically demanding environments.
All components are housed in an indoor-rated enclosure suitable for installation in metal-enclosed switchgear. The vacuum interrupters provide arc-free, maintenance-friendly operation, eliminating risks associated with oil or gas-based technologies. The unit includes provisions for manual charging and auxiliary signaling, enhancing operational flexibility and safety during maintenance or power outages.
Technical Parameters
Service Conditions
- Ambient temperature: -10 degC to +40 degC
- Altitude: <=1000 m above sea level
- Relative humidity: <=95% at 25 degC
- Environment: No hazardous gases, explosive dust, or severe vibration
Technical Data
| Parameter | ZN12-12 (12 kV) |
ZN12-40.5 (40.5 kV) |
|---|---|---|
| Rated voltage (kV) | 12 | 40.5 |
| Rated frequency (Hz) | 50 | 50 |
| Rated current (A) | 630 / 1250 / 1600 / 2000 / 2500 / 3150 | 1250 / 1600 / 2000 |
| Rated short-circuit breaking current (kA) | 20 / 25 / 31.5 / 40 | 25 / 31.5 |
| Rated short-circuit making current (peak, kA) | 50 / 63 / 80 / 100 | 63 / 80 |
| Rated short-time withstand current (kA/4s) | 20 / 25 / 31.5 / 40 | 25 / 31.5 |
| Power frequency withstand voltage (kV, 1 min) | 42 (phase-to-phase & phase-to-ground) 48 (isolation gap) |
95 (phase-to-phase & phase-to-ground) 118 (isolation gap) |
| Lightning impulse withstand voltage (kV, peak) | 75 (phase-to-phase & phase-to-ground) 85 (isolation gap) |
185 (phase-to-phase & phase-to-ground) 215 (isolation gap) |
| Mechanical life (operations) | 10,000 | 10,000 |
| Electrical life (at rated current) | 10,000 | 10,000 |
Installation & Wiring
Installation Diagram
The ZN12 vacuum circuit breaker is designed for fixed or withdrawable installation in metal-enclosed switchgear. Adequate clearance must be maintained around the unit to ensure safe operation, facilitate maintenance access, and allow proper heat dissipation during continuous service.
Safety Notice: Ensure all mounting surfaces are level and secure. Verify clearances per local electrical codes before energizing.
Selection & FAQs
Selection Guide
- Select the ZN12-12 or ZN12-40.5 platform from system voltage; do not combine current, fault or insulation data across the two voltage classes.
- For 12kV choose 630A–3150A and 20kA–40kA; for 40.5kV choose 1250A–2000A and 25kA or 31.5kA, subject to available pairings.
- Verify the matching four-second withstand, peak-making and phase/earth plus open-gap insulation levels against protection and insulation studies.
- Select fixed or withdrawable installation and confirm switchgear dimensions, primary contacts, stroke, interlocks, shutters, control plug and grounding interface.
- Specify spring-mechanism control voltage, motor, trip/close coils, auxiliary contacts, relay logic, local/manual operation and required switching sequence.
Frequently Asked Questions
Q1: Can the ZN12-12 breaker operate in 40.5kV networks?
No, the ZN12-12 is strictly rated for 12kV systems. For 40.5kV applications, you must select the ZN12-40.5 model. Contact our engineering team for voltage-specific selection assistance.
Q2: What is the maximum short-circuit breaking current for 12kV models?
The ZN12-12 supports a maximum rated short-circuit breaking current of 40kA. Available standard ratings include 20, 25, 31.5, and 40kA. Specify your exact system fault level during ordering.
Q3: Are high-altitude installations supported for this vacuum circuit breaker?
Standard installation is limited to altitudes of 1000 meters or less above sea level. For higher elevations, derating or special design modifications are required. Please contact us for altitude-specific engineering details.
Q4: Which rated currents are available for the 40.5kV vacuum breaker?
The ZN12-40.5 model offers rated currents of 1250A, 1600A, and 2000A. Custom current ratings are subject to factory confirmation. Provide your load requirements for precise configuration.
Q5: How are factory tests documented before shipment?
Standard routine testing documentation is subject to confirmation based on project requirements. We provide detailed factory test reports upon formal request. Contact our procurement department for exact testing scopes.
Q6: Where is this indoor high-voltage vacuum circuit breaker applied?
It is primarily used in indoor AC power systems for protection and control. Suitable for industrial facilities, power plants, and substations. Ensure the environment is free from hazardous gases and severe vibration.