Modular design and intelligent monitoring ensure 24/7 operation of critical cross-sea tunnel infrastructure
In Shenzhen, a core transportation hub in the Guangdong-Hong Kong-Macao Greater Bay Area, the Mawan Undersea Tunnel, the first cross-sea tunnel, is approximately 8.05 kilometers long, 1.1 kilometers of which lies beneath the sea. The humid tunnel environment and the high chloride content and corrosive nature of the seabed strata place high demands on the power supply system. With its high reliability, intelligent monitoring, and modular design, the ABB SafePlus series of ring main units provides continuous and stable power supply for critical tunnel loads, making it an ideal choice for industrial power monitoring.
What is the ABB SafePlus Ring Main Unit?
ABB SafePlus is a ring main unit power monitoring device designed specifically for industrial environments. Its fully insulated and sealed gas chamber design withstands humidity, salt spray, and extreme temperatures. Its modular design enables rapid isolation of single-chamber faults, protecting other systems and ensuring continuous power supply to critical infrastructure such as tunnels.
Challenges of Tunnel Power Distribution
The Mawan Undersea Tunnel encountered the following power distribution challenges during its construction and operation:
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Highly corrosive and humid conditions under the seabed
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Securing critical loads such as lighting, ventilation, and fire protection around the clock
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The system needed to support independent power supply from dual-ring networks to prevent single-point failures from causing power outages
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Limited space inside the tunnel required a compact design to reduce occupancy costs

Solutions provided by ABB
ABB partnered with Shenzhen Oster Electric to provide a customized SafePlus Ring Main Unit Solution:
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Dual-ring network matching design: Each distribution room is equipped with two independent power supplies to ensure power continuity.
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Modular structure: If a single gas chamber fails, only that chamber is shut down, quickly restoring power to other chambers.
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Intelligent safety protection: High-vacuum interrupter circuit breakers, mechanical interlocking, and pressure relief systems ensure personnel and equipment safety.
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Compact and durable: Space-saving, waterproof and condensation-resistant, suitable for submarine and humid environments.
Technical Highlights and Advantages
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Fully sealed gas tank design: Ensures safe isolation of live components.
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High-vacuum interrupter circuit breakers: Strong interrupting capacity to meet high load demands.
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Modular power supply: Rapid fault isolation, reducing downtime risks.
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IP67 protection rating: Ensures stable operation in harsh environments such as tunnels.
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Intelligent monitoring system: Real-time monitoring of voltage, current, and equipment status, providing early warning.
Implementation Steps
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Site survey and assessment of the tunnel and distribution room environment.
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Customized dual-ring network design and SafePlus Power Distribution Solution
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Installation of Ring Main Units and Monitoring Equipment
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System Commissioning and Emergency Power Supply Drills
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Continuous monitoring and maintenance after commissioning ensures stable 24/7 power supply
Application Benefits
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Power Reliability: Critical loads operate continuously without interruption
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Reduced Maintenance Costs: Modular design facilitates rapid troubleshooting
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Space Optimization: Compact design conserves space within the tunnel
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Extended Equipment Life: Waterproof, anti-condensation, and anti-corrosion design
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Intelligent Management: Real-time monitoring and early warning improves O&M efficiency
Summary
ABB SafePlus Ring Main Units, with their modular, intelligent, and highly reliable design, provide a solid power supply for the Shenzhen Mawan Undersea Tunnel. Whether for tunnel power distribution, rail transit, or critical loads in industrial parks, SafePlus ensures 24/7 secure power supply and is an ideal choice for industrial power monitoring and distribution system upgrades.
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Contact Information
Manager: Leonia