The Fixed Side-Mounted Type VS1 indoor high voltage vacuum circuit breaker (hereinafter referred to as the circuit breaker) is an indoor switchgear used in 12kV Power Systems. It serves as a protection and control unit for power grids and industrial and mining enterprises. It is suitable for switching various types of loads and for applications requiring frequent operations and multiple interruptions of short-circuit currents.
This product adopts a newly developed operating mechanism. The primary part of the VS1 circuit breaker can be equipped with internationally branded solid-sealed poles, which integrate the vacuum interrupter and the main conductive components into a single sealed unit. This design effectively protects the interrupter from impacts, dust, and condensation, offering excellent environmental adaptability and significantly reducing operation and maintenance costs.
It truly realizes maintenance-free performance for the primary circuit and low-maintenance requirements for the operating mechanism. The operating mechanism is integrated with the circuit breaker body and has passed type tests, achieving an E2 level of electrical endurance and an M2 level of mechanical endurance.
| No. | Item | Unit | Data |
| 1 | Rated Voltage | kV | 12 |
| 2 | Maximum Working Voltage | kV | 12 |
| 3 | Rated Current | A | 630, 1250; 630, 1250; 630, 1250, 1600, 2000, 2500, 3150, 4000 |
| 4 | Rated Short-Circuit Breaking Current | kA | 20; 35; 31.5; 40 |
| 5 | Rated Short-Circuit Making Current | kA | 50; 63; 80; 100 |
| 6 | Rated Peak Withstand Current | kA | 50; 63; 80; 100 |
| 7 | Rated Short-Time Withstand Current | kA | 20; 25; 31.5; 40 |
| 8 | Rated Insulation Level | Power Frequency Withstand Voltage (before & after breaking) | 42 (contact gap: 48); 2 (secondary circuit insulation) |
| Impulse Withstand Voltage (before & after breaking) | 75 (contact gap: 84) | ||
| 9 | Rated Operating Sequence | Open—0.3s—Close-Open—180s—Close-Open | |
| 10 | Mechanical Life | operations | 10,000 |
| 11 | Rated Short-Circuit Breaking Times | operations | 30 |
| 12 | Operating Mechanism Rated Closing Voltage (DC) | V | 110, 220 |
| 13 | Operating Mechanism Rated Opening Voltage (DC) | V | 110, 220 |
| 14 | Contact Gap | mm | 11±1 |
| 15 | Over-Travel (Contact Spring Compression Length) | mm | 3.5±0.5 |
| 16 | Three-Phase Opening/Closing Asynchronism | ms | ≤2 |
| 17 | Contact Closing Bounce Time | ms | ≤2 |
| 18 | Average Opening Speed | m/s | 0.9–1.2 |
| 19 | Average Closing Speed | m/s | 0.4–0.8 |
| 20 | Opening Time | At Maximum Operating Voltage | ≤0.05 s |
| At Minimum Operating Voltage | ≤0.08 s | ||
| 21 | Closing Time | s | 0.1 |
| 22 | Main Circuit Resistance per Phase | μΩ | <50 (630A); <45 (1250A); <35 (1600–2000A) |
| 23 | Permissible Cumulative Wear of Contacts | mm | 3 |
The demand for reliable, safe, and efficient electrical distribution has grown significantly with the rapid expansion of industrial facilities, commercial complexes, and urban infrastructure. Circuit breakers play a vital role in ensuring safety and operational stability in electrical networks by interrupting fault currents and protecting systems from damage. Among the advanced solutions in the market, the VS1 indoor high voltage vacuum circuit breaker 12kV Fixed Side-Mounted has become a preferred choice for many power distribution applications.
This article provides a comprehensive overview of the VS1 vacuum circuit breaker, explaining its design principles, performance advantages, technical specifications, applications, and long-term benefits. It also highlights why this model stands out in the high-voltage switching equipment category.
A vacuum circuit breaker (VCB) is a type of switchgear device designed to interrupt current flow in high-voltage networks using a vacuum as the arc-extinguishing medium. The VS1 Indoor High Voltage Vacuum Circuit Breaker belongs to a family of indoor, fixed, side-mounted breakers designed specifically for 12kV voltage class systems.
Unlike traditional oil or SF6 circuit breakers, vacuum technology ensures environmental safety, minimal maintenance, and long service life, making it suitable for modern power distribution networks.
The VS1 breaker’s side-mounted, fixed design enhances installation flexibility, reduces space requirements, and ensures robust protection in medium-voltage indoor switchgear setups.
The VS1 breaker is recognized for a range of advanced features that ensure reliability, safety, and operational efficiency:
Rated Voltage: 12kV, suitable for medium-voltage distribution systems.
Fixed Side-Mounted Structure: Simplifies installation and provides mechanical strength.
Vacuum Interruption Technology: Uses vacuum arc-extinguishing chambers for arc control.
High Breaking Capacity: Handles fault currents reliably, ensuring network stability.
Long Mechanical and Electrical Life: Minimal wear and low maintenance requirements.
Compact Design: Saves space in indoor substations or switchgear rooms.
Safety Protection: Built-in interlocking mechanisms to avoid operational errors.
Adaptability: Compatible with various types of switchgear assemblies.
While specifications may vary slightly by configuration, the typical VS1 Indoor High Voltage Vacuum Circuit Breaker 12kV Fixed Side-Mounted includes:
Rated Voltage: 12kV
Rated Current: 630A, 1250A, 1600A, or higher depending on model
Rated Frequency: 50/60Hz
Rated Short-Circuit Breaking Current: Up to 25kA or 31.5kA
Rated Short-Circuit Making Current: 63kA or above
Mechanical Life: 10,000 operations or more
Operating Mechanism: Spring-stored energy type, electrically and manually operable
Mounting Type: Fixed, side-mounted, suitable for indoor switchgear
These technical parameters ensure robust performance and compliance with international standards for medium-voltage equipment.
The VS1 breaker provides numerous benefits, making it one of the most popular choices in the 12kV medium-voltage range:
The vacuum arc-extinguishing chamber offers exceptional reliability, reducing the risk of failures and extending operational life.
Unlike SF6 gas breakers, vacuum technology is non-polluting and does not contribute to greenhouse gas emissions.
Due to minimal contact wear, the breaker requires little maintenance over its lifespan.
Integrated safety locks, interlocks, and insulation barriers protect operators from accidental faults.
Its side-mounted, fixed design ensures space-saving installation, perfect for indoor switchgear rooms with limited space.
Long life, reduced downtime, and minimal maintenance contribute to overall cost efficiency.
The VS1 Indoor High Voltage Vacuum Circuit Breaker 12kV Fixed Side-Mounted finds applications across industries and sectors requiring stable and secure power distribution:
Power Generation Plants: Protecting auxiliary and distribution systems.
Industrial Facilities: Heavy machinery and manufacturing lines requiring uninterrupted power.
Commercial Buildings: Shopping centers, office complexes, and hospitals.
Urban Infrastructure: Metro systems, airports, and smart grids.
Mining and Energy: Safety-critical operations in high-demand environments.
Utilities and Substations: Part of medium-voltage distribution switchgear.
Its adaptability makes it a versatile solution for various medium-voltage indoor environments.
The fixed side-mounted structure of the VS1 breaker offers several engineering and operational advantages:
Mechanical Stability: Secure installation with reduced vibration.
Ease of Operation: Simple handling for both manual and electric operations.
Space Optimization: Side-mounting allows better equipment arrangement in compact switchgear rooms.
Lower Installation Costs: Fixed design avoids complex moving parts.
This design ensures both operational safety and reduced complexity, making it ideal for long-term indoor applications.
The VS1 uses vacuum interrupters to extinguish electrical arcs. When contacts separate during a fault, an arc is formed but quickly extinguished due to the high dielectric strength of the vacuum medium. This enables rapid arc suppression and minimal damage to contacts.
Key steps in the working principle:
Normal Operation: Contacts remain closed, allowing current to flow.
Fault Detection: Relay protection signals the breaker to open.
Arc Formation: As contacts separate, an arc briefly forms.
Arc Extinction: The vacuum extinguishes the arc within microseconds.
Circuit Isolation: Current flow is interrupted, protecting equipment.
This simple yet highly effective mechanism contributes to the durability and safety of the VS1 breaker.
When compared with oil, air, or SF6 circuit breakers, the VS1 vacuum breaker offers distinct advantages:
Versus Oil Breakers: No risk of fire hazards or oil leaks.
Versus Air Breakers: Smaller size, faster operation, and higher reliability.
Versus SF6 Breakers: Environmentally safe, with no gas leakage or greenhouse effect.
Thus, the vacuum circuit breaker is widely regarded as the best solution for medium-voltage indoor use.
The VS1 breaker is designed to meet international standards such as:
IEC 62271-100 (High-voltage switchgear and controlgear)
GB/T standards (China National Standards for circuit breakers)
ISO quality management certifications
Compliance ensures safety, reliability, and global acceptance in power distribution networks.
Although low-maintenance, periodic checks are necessary to maximize performance:
Visual Inspection: Checking contacts, insulation, and mechanism alignment.
Operational Tests: Ensuring proper tripping and closing actions.
Lubrication: Occasional lubrication of moving parts for smooth operation.
Contact Wear Monitoring: Ensuring contacts remain within tolerance levels.
With proper care, the VS1 breaker can last 20 years or more, offering excellent lifecycle value.
With the rise of smart grids, renewable energy integration, and automation, demand for reliable indoor breakers like the VS1 will continue to grow. Future trends include:
Integration with IoT-based monitoring systems.
Enhanced safety through digital trip units.
Even more compact designs for urban power networks.
The VS1 12kV Fixed Side-Mounted Vacuum Circuit Breaker remains highly relevant in this evolving landscape.
The VS1 Indoor High Voltage Vacuum Circuit Breaker 12kV Fixed Side-Mounted is a reliable, efficient, and environmentally friendly solution for medium-voltage indoor applications. With its robust design, superior safety features, low maintenance requirements, and proven vacuum technology, it ensures uninterrupted protection for industrial, commercial, and utility networks.
For power engineers, facility managers, and electrical infrastructure planners, the VS1 breaker represents an ideal choice for long-term, safe, and cost-effective energy distribution.
Phone: +8613736779975
E-mail: sales@vcbbreaker.com
Address: 66 Punan Road, Yueqing Economic Development Zone, Zhejiang, China
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