VS1 Vacuum Circuit Breaker

Are you worried that in the event of a short circuit on a high-voltage line, the circuit breaker, due to its insufficient arc-extinguishing capability, will be unable to cut off the current, resulting in the burning of the transformer or even an explosion? In a 10kV high-voltage environment, the arc energy is enormous. Traditional oil circuit breakers or ordinary switches are no longer able to meet the strict safety requirements of modern power grids. The VS1 Vacuum Circuit Breaker from Junray Electrical was specifically designed to address this core pain point. We use vacuum as the arc-extinguishing medium and leverage its extremely high insulation strength and arc-extinguishing capability to quickly extinguish the arc at the zero-crossing point of the current. This means that no matter how severe the short circuit fault on the line is, it can reliably cut off the power supply, prevent the expansion of the fault, and completely eliminate your concerns about the high-voltage breaking capacity.

Vacuum Arc Interruption and Precise Protection

The core competitiveness of VS1 Vacuum Circuit Breaker lies in its advanced arc interruption chamber design and reliable spring operating mechanism:

Superb interrupting capacity: Utilizing a dedicated vacuum arc interruption chamber, the contactor has low contact resistance and short arc duration. Compared to older equipment, it can interrupt larger short-circuit currents (up to 40kA), perfectly adapting to the harsh conditions of 10kV high-voltage lines, ensuring that it can still "break and extinguish" in extreme faults.

Dual protection mechanism: Equipped with precise overload and short-circuit protection functions. When an abnormality in the line current is detected, in conjunction with the relay protection device, it can automatically and rapidly disconnect the circuit, effectively protecting expensive high-voltage equipment such as transformers and cables, and preventing permanent damage due to overcurrent.

Standardized compatibility: Compact in size, it can be perfectly installed on the vehicle, not only saving the internal space of the switch cabinet, but also making maintenance and repair extremely convenient, with operation achievable by simply pushing in or pulling out.

Junray Electrical's Quality Assurance

As a professional Manufacturer with profound technical expertise, Junray Electrical strictly adheres to the national standards of VS1 vacuum circuit breakers during production. Our factory is equipped with advanced vacuum casting and assembly lines, ensuring that every circuit breaker meets industrial standards.

This VS1 Vacuum Circuit Breaker features a highly reliable spring-stored operating mechanism, with crisp and precise opening and closing actions, long mechanical lifespan, and extremely low failure rate. Each circuit breaker undergoes strict power-on debugging, power frequency withstand voltage tests, loop resistance tests, and mechanical characteristic tests before leaving the factory, ensuring stable operation at rated currents ranging from 630A to 3150A, providing you with long-lasting high-voltage security protection.

Technical Specifications 

Applicable scenarios:

Industrial power distribution: 10kV incoming and outgoing cabinets for factories, protecting large motors and transformers.

Commercial buildings: High-voltage power receiving cabinets for high-rise buildings and office buildings.

Substations: Core protective components of various 10kV indoor substations.

One-stop solution

Choosing Junray Electrical is not merely choosing a Supplier, but choosing a reliable partner for high-voltage safety. We have a professional team of 50 people, including 5 full-time quotation engineers, who can provide you with fast and precise customized services.

We promise to offer 7×24-hour global rapid response. If you are looking for a product that can perfectly fit the KYN28 cabinet, has strong breaking capacity and is reliable, don't hesitate any longer. Contact us immediately to get free technical consultation and quotations, and let Junray Electrical build a safe, stable and efficient power distribution system for you.

Retrofit Project Overview

I. Project Summary

This project involves the upgrade and retrofit of 10kV high-voltage switchgear at an industrial park's 110kV substation. The existing 10kV feeder panels were equipped with outdated, early-model vacuum circuit breakers that had been in service for a long time and suffered from mechanical mechanism aging. On-site issues frequently included closing coil burnout, mechanism jamming, energy storage failure, and failure to operate during faults. When short-circuit faults occurred, the switches failed to instantaneously clear the fault, causing upstream protection devices to trip (sympathetic tripping). This resulted in widespread power outages across the area, severely impacting continuous plant production and the reliability of the distribution network power supply. The outdated switches exhibited degraded arc-extinguishing capabilities and mechanical characteristics that fell short of standards, failing to meet current operational requirements for frequent switching and rapid fault clearing in the distribution network.

To fundamentally resolve risks associated with switchgear failure to operate, maloperation, and mechanical defects, and to enhance short-circuit fault clearing capabilities, all aging switches in the substation are being replaced with VS1 indoor high-voltage vacuum circuit breakers. These serve as the core protective switches for the 10kV distribution system, handling load switching as well as the rapid clearing of overload and short-circuit faults.

II. Issues Prior to Retrofit

Frequent closing coil burnout and mechanism jamming: Due to improper auxiliary switch switching and mechanical limit deviations, the circuit failed to disconnect promptly after the closing operation completed. This caused the coil to remain energized and overheat, leading to burnout and frequent closing failures.

Energy storage mechanism failure and inability to perform repeated operations: Aging or jamming of the energy storage microswitch and contact erosion prevented automatic energy storage after the closing spring released. This limited the unit to single operations, failing to meet reclosing requirements.

Failure to operate during short-circuit faults, causing sympathetic tripping: Degraded arc-extinguishing performance and insufficient opening speeds prevented rapid fault clearing during line short-circuits. This triggered upstream switches to operate, thereby expanding the scope of the power outage.

Aging and overheating of tulip contacts: Fatigue and annealing of the moving contact springs resulted in insufficient clamping force. Long-term operation led to increased contact resistance, causing contact overheating and risks of partial discharge during peak load periods. High O&M workload and low test pass rates: Aging switchgear exhibits mechanical characteristics exceeding limits and degraded insulation; annual preventive tests consistently show multiple parameters failing to meet standards, making it impossible to completely eliminate hidden hazards.

III. Equipment Configuration Plan

In accordance with 10kV high-voltage distribution standards and substation operating conditions, the project involves replacing all units with VS1 fixed/draw-out vacuum circuit breakers. These units utilize vacuum arc extinguishing and spring-operated mechanisms, offering advantages such as high operating speed, long mechanical life, thorough arc extinction, and maintenance-free operation, serving as the core protection equipment for the 10kV distribution lines.

Core Equipment Specifications

Model: VS1/1250A-25kA Indoor High-Voltage Vacuum Circuit Breaker

Rated Voltage: 12kV (suitable for 10kV medium-voltage distribution systems)

Rated Current: 1250A (meets current-carrying requirements for heavy plant loads)

Short-Circuit Breaking Current: 25kA (capable of rapidly clearing severe phase-to-phase and phase-to-ground short-circuit faults)

Arc-Extinguishing Medium: High-vacuum interrupter (no free gases; no risk of combustion or explosion)

Operating Mechanism: Integrated spring energy-storage mechanism (stable opening/closing speeds and excellent mechanical characteristics)

Protection Functions: Capable of interrupting load current, overload current, and short-circuit current; possesses genuine fault-breaking capability

Associated Testing: Post-replacement verification includes mechanical characteristic testing, insulation withstand voltage tests, loop resistance checks, and full validation of opening/closing times.

IV. Construction and Application Highlights

Vacuum Arc Extinction – Safe and Hazard-Free: Relies on a high-vacuum environment for arc extinction; contains no oil or SF6 gas and poses no risk of combustion or explosion. Arc extinction speed far exceeds that of older low-oil switches, ensuring clean and thorough fault clearing.

Stable Mechanism – Eliminates Coil Burnout: Optimized auxiliary switch logic and mechanical limiters ensure the circuit is cut off the instant the closing operation completes, completely resolving the common issue of coil burnout caused by prolonged energization.

Automatic Energy Storage – Supports Reclosing: High-precision energy-storage microswitches ensure sensitive and reliable operation; automatic energy storage after closing meets requirements for grid reclosing and frequent operation scenarios. Excellent contact performance and controllable temperature rise: The tulip contact clamping structure is optimized to ensure stable contact resistance; there is no overheating or partial discharge during long-term full-load operation.

Maintenance-free with an ultra-long service life: The vacuum interrupter offers stable sealing and minimal mechanical wear, eliminating the need for periodic gas replenishment or oil changes, thereby significantly reducing operation and maintenance costs.

V. Operational Results After Retrofitting

Complete elimination of failure-to-operate and maloperation issues: Opening and closing operations are crisp and decisive, and all mechanical characteristic parameters meet standards; there are no issues with mechanism jamming or energy storage failure.

Prevention of upstream tripping and containment of fault scope: Short-circuit faults are cleared precisely and rapidly; the local switch operates reliably without triggering upstream breakers, significantly enhancing power supply reliability.

Zero equipment overheating and stable insulation: Circuit resistance is within limits and contact quality is excellent; no overheating or abnormal discharge noise occurs during peak load periods throughout the year.

Reliable reclosing functionality: Automatic reclosing restores power after transient faults, effectively minimizing outage duration for users.

Successful testing and acceptance: All tests—including mechanical characteristics, insulation, withstand voltage, and current-carrying capacity—meet standards; the equipment successfully passed the power utility's preventive tests and standardization acceptance inspections.

VI. Case Summary

The VS1 vacuum circuit breaker serves as the core protective switch for 10kV switchgear and is the primary device in distribution networks capable of interrupting short-circuit faults. Key distinction: While the FLN36 load break switch can only make and break load currents—lacking short-circuit interruption capability—the VS1 vacuum circuit breaker can interrupt short-circuit, overload, and load currents, providing genuine protection. Offering advantages such as vacuum arc extinguishing, mechanism stability, maintenance-free operation, long service life, and high safety and reliability, it is currently the most widely used and standardized high-voltage switchgear for industrial and mining facilities, residential complexes, and substations.

FAQ

Question: In which cabinet types can this VS1 Vacuum Circuit Breaker be used?

Answer: It is mainly designed for KYN28 AC Metal-Enclosed Switchgear, and it can also be compatible with XGN2 and other fixed high-voltage cabinets. Its standardized size and installation holes ensure perfect compatibility with mainstream cabinet types.

Question: Does the vacuum interrupter require maintenance?

Answer: The vacuum interrupter is maintenance-free. It is sealed within an insulating cylinder and is not affected by external dust or moisture. Only regular mechanical characteristic checks and loop resistance tests are required, significantly reducing the maintenance workload.

Question: Is it possible to customize the rated current and breaking capacity?

Answer: Yes, it is possible. We can customize different current levels such as 630A, 1250A, 1600A, 2000A, 2500A, 3150A, and different breaking capacities such as 20kA, 25kA, 31.5kA, 40kA according to your project requirements, to ensure a precise match with your system parameters.