The main difference between VS1 sealed vacuum circuit breakers and non-sealed (also known as "naked" or "bulk") vacuum circuit breakers lies in the insulation and packaging method of their vacuum interrupter, which directly leads to differences in their structure, performance and application.
Core Differences at a Glance
| Feature Dimensions | VS1 Enclosed Vacuum Circuit Breaker | Non-Enclosed Vacuum Circuit Breaker |
|---|---|---|
| Core Structure | Integral Encapsulation (Solid-Encapsulated Pole): The vacuum interrupter, upper and lower lead-out sockets, and other key conductive components are cast using high-performance epoxy resin using the APG process to form a solid, integral structure. | Exposed Structure: The vacuum interrupter, insulating tie rod, and supporting porcelain bottle are individually visible and insulated by air. |
| Insulation Medium | Solid insulation (epoxy resin) is primary, supplemented by air. | Air insulation is primary. |
| Environmental adaptability | Extremely strong. Dust-proof, moisture-proof, condensation-proof, contaminant-proof, and repellent to small animals, suitable for harsh environments. | Weak. Requires high standards for cleanliness, humidity, and condensation, and is suitable for clean, dry indoor environments. |
| Mechanical properties and shock resistance | Good. The sealed pole structure is stable and integral, effectively resisting external mechanical stress and vibration. | Moderate. Components are connected by screws and connecting rods, which can easily loosen or shift under strong vibration. |
| Size and miniaturization | More compact. The reduced air insulation distance allows for miniaturization of switchgear. | Relatively bulky. Sufficient air insulation distance is required, resulting in a large size. |
| Reliability/maintenance-free | High. The main circuit is cured, unaffected by the environment, and virtually maintenance-free. | Low. The exposed arc chamber surface may degrade due to dust and condensation, requiring regular cleaning and maintenance. |
| Manufacturing process | The process is complex, requiring APG (Automatic Pressure Gelation) technology and equipment for one-step molding. |
The process is relatively simple, using a traditional prefabricated structure. |
| Heat dissipation | Slightly inferior. Epoxy resin's thermal conductivity is not as good as air, but design optimization (such as adding heat sinks) can meet requirements. |
Good. Major components are exposed to air, providing excellent heat dissipation through natural convection. |
| Cost | Manufacturing costs are relatively high, but overall maintenance costs are low, and the total lifecycle cost may be lower. |
Manufacturing costs are relatively low, but ongoing maintenance costs may be high. |
| Visibility | The external condition of the vacuum interrupter (such as color changes) cannot be directly observed. | Direct access to the arc chamber and other components facilitates visual inspection. |
Detailed Explanation and Analysis
1. Structural Principle: Fundamental Difference in Packaging
VS1 Solid-Sealed Type:
The core innovation lies in the "solid-sealed pole." During manufacturing, the vacuum interrupter (the core of the circuit breaker, responsible for interrupting the current), upper and lower conductive rods, and other components are molded in a single step using the APG process, similar to the molding of amber, using high-performance epoxy resin in a vacuum environment.
The advantage of this method is that components that previously relied on air insulation are now formed into a solid, insulated, and inseparable whole.
Non-Solid-Sealed Type:
This is the traditional structure of a vacuum circuit breaker. You can clearly see the cylindrical vacuum interrupter, which is secured to the frame by insulating rods and supporting porcelain bottles. Insulation between components and between components and grounded components is primarily achieved by maintaining a sufficient safe air distance.
2. Environmental Adaptability: Why are sealed switches superior?
This is the most critical difference between the two, directly determining their application scenarios.
VS1 sealed switch: Because the main circuit is completely encapsulated in epoxy resin, dust, moisture, salt spray, corrosive chemicals, and even small animals (such as cockroaches and geckos) cannot reach the live parts. This significantly reduces creepage and flashover (short-circuit) accidents caused by dirt and condensation on the insulation surface. Therefore, it is particularly suitable for:
High-humidity areas (such as coastal areas and riverine areas)
Dusty and polluting industrial environments (such as cement plants, chemical plants, and mines)
Switchgear in compact installation spaces and poorly ventilated environments
Non-sealed switchgear: Its insulation relies entirely on the cleanliness of the air and component surfaces. In humid weather, if the temperature inside the switchgear fluctuates, condensation can easily form on the cold arc chamber surfaces and insulation components, causing a sharp drop in insulation strength and potentially causing accidents. Therefore, it can usually only be installed in a clean, dry, well-ventilated indoor distribution room, and requires regular cleaning and maintenance.
3. Reliability and Maintenance
The VS1 sealed type: By minimizing environmental impact, its main circuit insulation reliability is extremely high, achieving "maintenance-free" operation. Users only need to focus on the mechanical characteristics of the mechanism, significantly reducing the O&M workload and reliance on personnel experience.
Non-sealed types: Regular power outages (e.g., annually) are required. The cabinet door must be opened and the arc chamber surface and insulation support components must be cleaned with a cleaning agent such as anhydrous ethanol to check for cracks or creepage. This requires extensive maintenance and high personnel requirements.
4. Development Trends
Enclosed vacuum circuit breakers (such as the VS1) are the current and future mainstream and development direction for medium-voltage indoor switchgear. Their superior environmental adaptability and high reliability meet the demands of modern power systems for miniaturized, maintenance-free, and highly reliable equipment. Due to their cost advantages and technological maturity, non-sealed circuit breakers are still used in some standardized, environmentally friendly, legacy projects or in extremely cost-sensitive applications, but their market share is gradually shrinking.
Summary
A non-enclosed circuit breaker is like a sophisticated open bookshelf, with the books (interrupter chamber) exposed. This provides convenient access (good heat dissipation and easy observation), but it is susceptible to dust and moisture, requiring frequent care.
The VS1 enclosed circuit breaker is like a fully sealed all-in-one computer, with all core components enclosed. It is resistant to dust and splashes, durable, and requires little to no cleaning. However, you cannot directly see the internal chip status.
Therefore, if your budget allows, you require high power supply reliability, or your operating environment is uncertain or difficult, you should prioritize the VS1 enclosed vacuum circuit breaker. If your environment is ideal and your budget is limited, a non-enclosed circuit breaker is also a mature option.
For more information, please contact us.
Email:pannie@hdswitchgear.com.
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