Pressure Relief Safety Solution for Gas-Insulated Ring Main Units
Ⅰ. Problem Context
As a core component in urban power distribution networks, ring main units (RMUs) are widely used in residential areas, factories, and public buildings due to their compact structure, low cost, and high reliability. However, internal equipment failures or arc faults may generate high-temperature, high-pressure gas, leading to cabinet explosions that endanger personnel and equipment. While traditional sealed designs maintain insulation integrity, they fail to rapidly release sudden pressure surges. An active pressure relief mechanism is urgently needed to balance safety and sealing requirements.
Ⅱ. Innovative Pressure Relief Design
This utility model introduces a triple-stage cascade pressure relief structure, leveraging synergistic collaboration among the gas chamber, cable chamber, and a dedicated pressure relief chamber for precise pressure release during faults:
1. Core Structure
- Relief Chamber Layout: Positioned below the gas and cable chambers, physically isolated via perforated baffles.
- Wax-Sealed Vent Holes: Both the baffle between the gas chamber and relief chamber (first baffle) and the baffle between the cable chamber and relief chamber (second baffle) feature 9–18 wax-sealed vent holes.
- Redundant Venting Channels: The relief chamber’s right side includes 3–6 through-holes temporarily sealed with plugs, serving as secondary venting paths.
2. Smart Trigger Mechanism
- Normal Operation: High-melting-point sealing wax (resistant to routine equipment temperatures) ensures airtightness.
- Fault Conditions: Arc-induced high-temperature gas (> wax melting point) melts the wax, allowing gas to surge into the relief chamber for first-stage pressure reduction.
- Pressure Persistence: If pressure remains elevated, gas dislodges the plugs from through-holes, venting directly outside to prevent cabinet explosion.
3. Eco-Friendliness & Maintenance Optimization
- Recyclable Wax Film: Relief chamber walls feature film with pre-cut openings at all vent holes/plugs. Melted wax adheres to the film post-fault for easy cleanup and recycling.
- Green Insulation Medium: Gas chamber filled with air/nitrogen ensures zero-pollution venting, complying with environmental standards.
Ⅲ. Technical Advantages
|
Function |
Implementation Method |
Safety Benefit |
|
Precise Pressure Relief |
Wax MP matches fault temperature |
Responds within seconds; prevents pressure buildup |
|
Dual Relief Pathways |
Main (sealed holes) + Backup (through-holes) |
Phased pressure release; avoids single-point failure |
|
Zero Pollution |
Air/Nitrogen insulation medium |
Nontoxic, harmless vented gas |
|
Ease of Maintenance |
Film-adsorbed wax residue |
Lowers cleanup costs; enhances sustainability |
Ⅳ. Application Value
This three-tiered design—physical isolation, smart wax-triggered release, and redundant venting—resolves the conflict between RMU airtightness and safety:
- Reduces Equipment Damage: Suppresses shock pressure to protect cabinet integrity.
- Ensures Personnel Safety: Rapid venting prevents explosions and controls hazards.
- Lowers Lifecycle Costs: Recyclable wax and durable design minimize maintenance.
Ideal for: Urban grid ring main units, compact substations, and high-load industrial power distribution systems with stringent space/safety requirements.
Ⅴ. Conclusion
Featuring a simple mechanical structure and intelligent materials (high-MP wax), this pressure relief system delivers a leap in safety performance for RMUs. Combining reliability, eco-friendliness, and cost-efficiency, it stands as the ideal safety solution for next-generation smart power distribution equipment.
