Overview
The ZN85-40.5kV indoor high-voltage vacuum circuit breaker is engineered for three-phase AC 50Hz power systems with a rated voltage of 40.5kV. It is widely deployed in power plants, substations, and industrial facilities to reliably switch load currents, overload currents, and fault currents under normal and abnormal operating conditions.
Featuring an innovative upper-and-lower layout, the ZN85-40.5 significantly reduces installation depth while maintaining structural integrity. Its spring energy storage mechanism is fully integrated within the frame, forming a compact and inseparable unit with the moving and fixed components.
Model Designation
- Z: Vacuum circuit breaker
- N: Indoor type
- 85: Design sequence number
- 40.5: Rated voltage (kV)
- â¡: Rated current (A)
- â¡: Rated short-circuit breaking current (kA)
Construction
The closing operation begins when a motor charges the closing spring; upon activation of the closing electromagnet, the stored energy drives the mechanism to close the contacts while simultaneously preloading the opening spring and contact pressure spring. For opening, energizing the opening electromagnet triggers the tripping mechanism, releasing the energy stored in the opening spring to rapidly separate the contacts within the vacuum arc-extinguishing chamber.
Manual energy storage is achieved by inserting the manual handle into the operating mechanism and oscillating it approximately 60 times. Once energized, the breaker can be operated via the manual open/close buttons, ensuring operability even during control power loss.
Technical Parameters
Service Conditions
- Altitude: <=1000 meters
- Ambient temperature: -25 degC to +40 degC
- Relative humidity: <=95% (daily average)
- Environment: No hazardous gases, explosive dust, or severe vibration
Technical Data
| Item (Parameter) |
Unit | Data |
|---|---|---|
| Rated Voltage | kV | 40.5 |
| Rated Current | A | 1250 1600 2000 |
| Rated Frequency | Hz | 50 |
| Rated Short-Circuit Breaking Current | kA | 25 31.5 |
| Rated Short-Circuit Making Current (Peak) | kA | 63 80 |
| 4s Rated Short-Time Withstand Current | kA | 25 31.5 |
| Rated Peak Withstand Current | kA | 63 80 |
| 1-Minute Power Frequency Withstand Voltage | kV | 95 |
| Lightning Impulse Withstand Voltage (Peak) | kV | 185 |
| Rated Operating Sequence | O-0.3s-CO-180s-CO | |
| Rated Short-Circuit Breaking Current Operations | Times | 20 |
| Mechanical Life | Times | 10000 |
| Opening Time | ms | <=80 |
| Single Capacitor Bank Breaking Current | A | 630 |
| Back-to-Back Capacitor Bank Breaking Current | A | 400 |
| Rated Operating Voltage | V | -110/~110, -220/~220 |
Installation & Wiring
Installation Diagram
The ZN85-40.5kV breaker features a compact upper-lower layout that minimizes required switchgear depth. Ensure adequate clearance for manual operation, cable termination, and maintenance access during installation.
Outline Dimensions
| Dimension | Value (mm) |
|---|---|
| Height | 2100 |
| Width | 1200 |
| Depth | 2800 |
| Mounting Hole Spacing (Vertical) | 630 |
| Mounting Hole Spacing (Horizontal) | 700 |
| Phase Spacing | 300 |
Selection & FAQs
Selection Guide
- Confirm a 40.5kV, 50Hz indoor system and select 1250A, 1600A or 2000A after applying enclosure, ambient and altitude derating.
- Choose 25kA or 31.5kA breaking capacity above the calculated fault level and verify the matching 4-second and 63kA/80kA peak withstand duties.
- Confirm the 95kV one-minute power-frequency and 185kV lightning-impulse withstand levels meet the system insulation coordination.
- Specify AC or DC 110V/220V control voltage and coordinate the charging motor, trip/close coils, auxiliary contacts, relays and O–0.3s–CO–180s–CO sequence.
- Verify switchgear dimensions, 300mm phase spacing, mounting pattern, clearances, grounding, cable access and maintenance space against approved drawings.
Frequently Asked Questions
Q1: What is the rated short-circuit breaking current for this 40.5kV vacuum breaker?
It offers 25kA or 31.5kA rated short-circuit breaking current. Select the appropriate capacity based on your system fault level. Contact us for specific project sizing.
Q2: Can this indoor circuit breaker operate at altitudes above 1000 meters?
Standard models are rated for altitudes up to 1000 meters. For higher elevations, derating or custom design is required. Please confirm your site altitude during inquiry.
Q3: Which insulation levels does the 40.5kV vacuum circuit breaker support?
It features a 95kV 1-minute power frequency withstand voltage and 185kV lightning impulse withstand voltage. These parameters ensure reliable dielectric performance in 40.5kV indoor switchgear. Request the full technical datasheet for details.
Q4: What routine factory tests are performed before shipping the ZN85 breaker?
Standard tests include mechanical operation, power frequency withstand, and contact resistance measurements. Specific type tests or third-party certifications are subject to confirmation. Request the test report template for details.
Q5: How long is the lead time for customized 40.5kV circuit breakers?
Lead times depend on the rated current and customization requirements. Standard configurations and custom builds are subject to confirmation. Contact our sales team for exact delivery schedules.
Q6: Where is the ZN85-40.5kV vacuum circuit breaker typically applied?
It is designed for indoor high-voltage switchgear in power plants, substations, and industrial networks. It protects 40.5kV systems under normal and fault conditions. Specify your application scenario for optimal configuration.
Q7: How many mechanical operations can this high-voltage vacuum breaker perform?
The ZN85 model guarantees a mechanical life of 10,000 operations. It also supports 20 rated short-circuit breaking operations. Verify maintenance intervals with your technical team.