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The ZN85-40.5 Indoor Vacuum Circuit Breaker guide is a state-of-the-art medium voltage (MV) power protection device designed for three-phase AC 50Hz, 40.5kV power systems. As a key component in modern substations, power plants, and industrial environments, this vacuum circuit breaker delivers high-performance switching capability for load current, overload current, and fault current scenarios. Its compact structure, outstanding electrical and mechanical properties, and long service life make it a preferred solution for reliable, frequent operations under harsh conditions.
Key Features of ZN85-40.5 Vacuum Circuit Breaker
- Advanced Arc-Extinguishing Design: The arc extinguishing chambers are independently housed in epoxy resin insulated cylinders, ensuring excellent electrical insulation, minimized creepage, and reduced product volume. Each phase is individually insulated, which enhances safety and overall reliability.
- Compact and User-Friendly Layout: The vacuum interrupters, drive mechanisms, and primary conductor systems are vertically arranged in an upper-lower configuration, which reduces the device’s depth and makes it suitable for modern compact switchgear cabinets.
- Maintenance-Free Solid-Sealed Pole: The insulating cylinder integrates vacuum interrupters and current path components into one solid-sealed structure. This design allows for long-term operation without the need for routine maintenance.
- Flexible Installation: The breaker is available in both fixed and withdrawable configurations, suitable for XGN-40.5, KYN61 switchgear, and compact box-type substations.
- Compliant with Standards: Fully compliant with IEC 62271-100, ensuring reliable performance in medium voltage switching applications globally.
Environmental and Operating Conditions
The ZN85-40.5 Vacuum Circuit Breaker is designed to operate reliably in diverse environments:
- Ambient Temperature: -10°C to +40°C
- Altitude: ≤1500 meters
- Relative Humidity: ≤95% (daily), ≤90% (monthly)
- Earthquake Resistance: Up to 8 degrees
- Free from flammable gases, severe pollution, chemical corrosion, and vibrations
Applications
This vacuum circuit breaker is ideal for:
- Power plants and substations
- Industrial and mining operations
- Medium voltage switchgear (fixed or drawout type)
- Systems requiring frequent switching and high short-circuit breaking capacity
Technical Parameters of ZN85-40.5 Vacuum Circuit Breaker
Electrical Parameters
| Item | Unit | Value |
|---|---|---|
| Rated Voltage | kV | 40.5 |
| Rated Frequency | Hz | 50 |
| Rated Current | A | 630, 1250, 1600, 2000, 2500 |
| Short-Circuit Breaking Current | kA | 25, 31.5 |
| Short-Time Withstand Current (RMS) | kA | 25, 31.5 |
| Peak Withstand Current | kA | 63, 80 |
| Short-Circuit Closing Current | kA | 63, 80 |
| Capacitor Bank Breaking Current (Single/Back-to-Back) | A | 600 / 400 |
| Short-Circuit Current Duration | s | 4 |
| Short-Circuit Breaking Times | Times | 20 |
| Operating Sequence | – | O-0.3s-CO-180s-CO |
| Main Circuit Resistance | μΩ | ≤65 |
| Operating Voltage | V (AC/DC) | 220 / 110 |
| Mechanical Life | Times | ≥10,000 |
Mechanical Parameters
| Item | Unit | Value |
|---|---|---|
| Open Contact Gap | mm | 18 ± 1 |
| Overtravel | mm | 5 ± 1 |
| Contact Bounce Time | ms | ≤3 |
| Phase Synchronism | ms | ≤2 |
| Average Opening Speed | m/s | 1.7 ± 0.2 |
| Average Closing Speed | m/s | 0.75 ± 0.2 |
| Opening Time | ms | ≤90 |
| Closing Time | ms | ≤60 |
| Wear Limit (Contact) | mm | 3 |
Mounting & Dimensions (Solid-Seal Type & Insulating Cylinder Type)
| Rated Current (A) | Breaking Current (kA) | Static Contact Size (mm) | Plum-Blossom Contact Type |
|---|---|---|---|
| 630 | 20/25/31.5 | Φ35 | CT-30 |
| 1250 | 31.5 | Φ49 | CT-30 |
| 1600 | 31.5 | Φ55 | CT-36 |
| 2000 | 31.5 | Φ79 | CT-48 |
| 2500 | 31.5 | Φ109 | CT-64 |
Actuator and Operation Mechanism
- Uses the 3AV3 spring operating mechanism known for its maturity and reliability.
- Simple design with output curves optimized for the 40.5kV vacuum interrupter’s characteristics.
- Mechanism supports both manual and automatic energy storage, enabling local or remote operation.
The ZN85-40.5 Vacuum Circuit Breaker is a cutting-edge, indoor high-voltage switching device designed for safe and efficient operation in demanding environments. Its compact structure, superior insulation, and mechanical reliability make it an ideal solution for 40.5kV medium voltage systems requiring high short-circuit performance and frequent operation. With a maintenance-free design and strong compliance with international standards, the ZN85-40.5 stands out as a trusted choice in modern power infrastructure.
