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The ZN28A-12/630-20 Vacuum Circuit Breaker is a highly reliable and efficient device designed for medium-voltage indoor applications, with a rated voltage of 12kV and a frequency of 50Hz. It is an essential component for protecting electrical systems in substations, industrial plants, and power distribution networks. The ZN28A-12 series complies with the GB1984-89 standard and is designed to provide optimal protection against overloads, short circuits, and faults, ensuring the safety and longevity of connected equipment.
Key Features of the ZN28A-12/630-20 Vacuum Circuit Breaker
The ZN28A-12 vacuum circuit breaker is designed with two main installation forms: an integrated structure and a separated structure. The integrated structure is known as the basic model (ZN28-12), while the separated structure is referred to as the ZN28A-12 type. This flexibility makes it suitable for various fixed switchgear systems, such as CClA(Z) and XGN2A-10(Z), offering versatility in installation and operation.
- Rated Voltage: The ZN28A-12 is designed for a rated voltage of 12kV, making it suitable for medium-voltage applications in industrial and power grid systems.
- Rated Current: Available in multiple current ratings, including 630A, 1000A, 1250A, and 1600A, to accommodate different load requirements.
- Rated Short-Circuit Breaking Current: The breaker can handle short-circuit currents of up to 31.5kA, providing protection against fault conditions in the electrical system.
- Rated Short Circuit Closing Current: The breaker can withstand closing currents up to 80kA, ensuring the integrity of the system during fault interruptions.
- Mechanical Life: Designed for up to 10,000 operations, ensuring long-lasting performance and minimal downtime in industrial environments.
Technical Parameters of ZN28A-12/630-20 Vacuum Circuit Breaker
The following table provides detailed technical parameters for the ZN28A-12/630-20 Vacuum Circuit Breaker:
| No | Item | Units | Technical Parameters |
|---|---|---|---|
| 1 | Rated Voltage | kV | 12 |
| 2 | Rated Current | A | 630, 1000, 1250, 1600 |
| 3 | Rated Short-Circuit Breaking Current | kA | 20, 25, 31.5 |
| 4 | Rated Short Circuit Closing Current | kA | 50, 63, 80 |
| 5 | Rated Peak Withstand Current | kA | 50, 63, 80 |
| 6 | 4s Rated Short Circuit Withstand Current | kA | 20, 25, 31.5 |
| 7 | Rated Insulation Level | ||
| Power Frequency Withstand Voltage (Before/After Rated Breaking) | kV | 42 (fracture: 48) | |
| Impact Withstand Voltage (Before/After Rated Breaking) | kV | 75 (fracture: 84) | |
| 8 | Rated Operation Sequence | 75 (fracture: 84) | |
| 9 | Mechanical Life | Times | 10,000 |
| 10 | Rated Short Circuit Current Breaking Times | Times | 10,000 |
| 11 | Operating Mechanism Rated Closing Voltage (DC) | V | 50 |
| 12 | Operating Mechanism Rated Trip Current (DC) | V | 110, 220 |
| 13 | Contact Stroke | mm | 110, 200 |
| 14 | Overtravel (Contact Spring Compression Length) | mm | 11 ± 1 |
| 15 | Three-Phase Split and Close Bounce Time | ms | 3.5 ± 0.5 |
| 16 | Contact Closing Bounce Time | ms | ≤2 |
| 17 | Average Opening Speed | m/s | ≤2 |
| 18 | Average Closing Speed | m/s | 1.2 ± 0.2 |
| 19 | Opening Time (At the Highest Operating Voltage) | s | 0.6 ± 0.2 |
| 20 | Closing Time | s | ≤0.05 |
| 21 | Main Loop Resistance of Each Phase | μΩ | ≤0.08 |
| 22 | Dynamic and Static Contacts Allowable Wear Cumulative Thickness | mm | 0.1 |
Installation and Environmental Conditions
The ZN28A-12/630-20 Vacuum Circuit Breaker is designed for installation in fixed switchgear and requires an appropriate operating mechanism, such as the CD-10 electromagnetic mechanism or CT-8 spring operating mechanism. The breaker’s installation and the mechanical transmission should ensure that the main shaft’s rotation angle remains within 58° ± 1°, ensuring proper functionality.
Here are the recommended operating conditions for the ZN28A-12 circuit breaker guide:
- Ambient Temperature: The breaker can operate within a temperature range of -30°C to +40°C.
- Altitude: Suitable for installations up to 2000 meters above sea level.
- Wind Pressure: Can withstand wind pressure up to 700Pa (with a corresponding dry wind speed of 34m/s).
- Seismic Intensity: Can operate in areas with seismic intensity levels up to 8.
- Maximum Daily Temperature Difference: The maximum daily temperature difference should not exceed 25°C.
- Relative Humidity: Daily average relative humidity should not exceed 95%, and the monthly average should not exceed 90%.
- Environmental Conditions: It is designed to operate in environments free from explosive, flammable hazards, chemical corrosion, and severe vibrations.
Applications of the ZN28A-12 Vacuum Circuit Breaker
The ZN28A-12/630-20 Vacuum Circuit Breaker is specifically designed for use in medium-voltage electrical systems, such as those found in industrial plants, substations, and power distribution networks. It provides exceptional protection for electrical equipment, ensuring safety during faults like short circuits and overloads. The vacuum technology utilized in this breaker allows for efficient arc quenching, making it a reliable and cost-effective solution for modern electrical infrastructure.
This circuit breaker is commonly used in fixed-type switchgear systems, where it ensures quick fault isolation, reducing the risk of damage to electrical equipment and minimizing downtime. Its versatility and high breaking capacity make it suitable for a wide range of applications in both urban and industrial environments.
Advantages of Using the ZN28A-12 Vacuum Circuit Breaker
- Reliable Protection: With its high breaking capacity, the ZN28A-12 provides reliable protection against overloads, short circuits, and faults, ensuring the safety of critical electrical infrastructure.
- Low Maintenance: Thanks to its vacuum arc quenching technology, the breaker requires minimal maintenance, reducing operational costs and increasing system reliability.
- Long Service Life: Designed to last up to 10,000 operations, the ZN28A-12 offers a long service life, ensuring long-term performance and minimal replacement costs.
- Eco-Friendly Design: The vacuum technology used in this circuit breaker eliminates the need for oil or gas, making it an environmentally friendly option for modern electrical systems.
- Flexible Installation Options: The ZN28A-12 can be installed in both integrated and separated forms, providing flexibility for different switchgear configurations.
Conclusion
The ZN28A-12/630-20 Vacuum Circuit Breaker is a highly effective and reliable solution for protecting medium-voltage electrical systems. Its high breaking capacity, long mechanical life, and eco-friendly design make it a preferred choice for modern power distribution networks and industrial applications. With its versatility in installation, minimal maintenance needs, and exceptional performance, the ZN28A-12 ensures the safety and reliability of electrical infrastructure, making it a key component in the protection of electrical equipment worldwide.
