Outdoor Pole-Mounted SF₆ Load Break Switches: Advantages of Tank-Grounded Structure

The tank-grounded structure for outdoor pole-mounted SF₆ load break switches is the mainstream design in current distribution automation systems. Compared with earlier porcelain-column types, this structure offers significant advantages in safety, reliability, and maintenance-free operation.

The specific advantages of this structure are analyzed as follows:

1. Stable Insulation Performance

• Consistent Electric Field Distribution: The tank-grounded structure employs internal insulating bushings for lead-out connections, resulting in a relatively uniform and stable electric field distribution. Additionally, insulation status can be monitored in real time through gas pressure supervision.

2. Exceptional Environmental Adaptability

• Maintenance-Free Design: The primary circuit (contacts, arc extinguishing chamber, etc.) is completely sealed within a stainless steel tank filled with SF₆ gas, which possesses excellent insulation and arc-quenching properties. This fully protects the contact system from external salt spray, dust, moisture, and industrial pollution, effectively eliminating issues such as "pollution flashover" and "condensation."
• Long Service Life: Since the primary circuit is not subject to atmospheric corrosion, contact oxidation is extremely slow, resulting in significantly extended mechanical and electrical life. The design typically achieves over 20 years of maintenance-free operation, making it particularly suitable for installation in coastal areas or remote mountainous regions.
• Complete Isolation from Harsh Environments: The stainless steel sealed tank combined with SF₆ gas insulation completely isolates the primary circuit from the external atmosphere. The Rockwill RPS-T Series outdoor pole-mounted SF₆ load break switch features a main body constructed of stainless steel and corrosion-resistant aluminum alloy, with a mechanism enclosure rated at IP54 (dust-proof and water-resistant), offering excellent corrosion resistance.

Rockwill RPS-T SF6 Insulated 3 Position Load Break Switch

3. Compact Structure with Low Center of Gravity

• Small Size and Light Weight: SF₆ gas has an insulation strength 2–3 times that of air, allowing for minimal phase-to-phase and phase-to-ground clearances, thereby significantly reducing the overall switch footprint.
• Mechanical Stability: The tank-grounded structure has a low center of gravity, providing better wind and vibration resistance when mounted on poles. The transmission mechanism is also easier to miniaturize and modularize.

4. Easy Integration for Intelligence and Automation

• Sensor Integration: The metallic tank provides an ideal mounting platform for current transformers (CTs) and voltage sensors (PTs), facilitating the collection of line current, voltage, and SF₆ pressure signals.
• Actuator Compatibility: This structure readily accommodates the integration of motor-operated mechanisms and Feeder Terminal Units (FTUs), enabling automatic fault isolation and remote monitoring. It serves as a key node in building intelligent distribution networks.

5. Superior Safety Performance

• Internal Fault Containment: The metallic tank possesses high mechanical strength. In the event of an internal arc fault, the robust sealed enclosure effectively prevents arc ejection or the dispersal of internal components, minimizing impact on the surrounding environment and nearby equipment.
• Excellent Explosion-Proof Performance: The metallic tank is designed with exceptional mechanical strength. Should an extreme short-circuit fault generate an internal arc, the sturdy tank effectively contains the fault and prevents debris from being expelled, thereby avoiding secondary harm to pedestrians or equipment located beneath the pole.

The Rockwill outdoor pole-mounted SF₆ load break switch RPS-T Series built upon the fully sealed tank-grounded structure, has become a core device for sectioning and fault isolation in medium-voltage overhead distribution networks, leveraging its advantages of maintenance-free operation, high safety, and strong environmental adaptability.

This series features a stainless steel fully sealed gas tank with SF₆ gas insulation, fully enclosing the primary circuit contacts within the grounded tank to achieve efficient arc extinguishing and reliable insulation. After opening, the mechanically linked visual position indicator allows for clear confirmation of the isolation gap, ensuring maintenance safety.

The product comes standard with a lightweight spring-operated mechanism and a robust mechanical interlocking system. It supports both manual on-site operation via an insulating pole and motor-driven remote control, ensuring precise and reliable operation during long-term field service.
Edited From:Garca