The underground prefabricated substation is an advanced integrated power distribution solution designed with a split modular structure, consisting of:

• Underground transformer unit
• Prefabricated underground pit
• Low-voltage distribution cabinet integrated with lighting box system

The high-voltage unit and transformer are fully installed below ground level, while only the low-voltage cabinet and advertising lighting structure remain above ground.

This innovative design:

• Saves up to 80% of land occupation compared with conventional substations
• Significantly reduces electrical hazards and electromagnetic exposure
• Enhances urban aesthetics with integrated LED lighting systems

It is widely used in:

• Urban road lighting systems
• Green belts and landscape areas
• Airports and commercial centers
• Municipal squares and tourism zones
• Residential communities and highways

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🔹 Standards Compliance

• GB/T 17467 – High-voltage/Low-voltage Prefabricated Substations
• DL/T 537 – Technical Guidelines for Prefabricated Substations
• JB/T 10217 – Combined Transformer Units
• GB 7251.1 – Low-voltage Switchgear Assemblies

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🔹 Key Features

✔ Space-Saving Underground Design

• High-voltage and transformer units installed underground
• Reduces surface footprint to 1/5 of conventional European-style substations
• Ideal for dense urban environments

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✔ Energy-Saving & Low Operating Cost

• Equipped with S13 or SH15 amorphous alloy transformers
• No-load loss reduced by:
  • ~30% (S13)
  • ~80% (SH15 amorphous type)
• Close-load-center installation reduces cable losses and investment

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✔ High Safety Protection System

• Fully sealed high-voltage load switch (2-position / 4-position options)
• Full-range fuse protection
• Touch-proof, fully insulated cable connectors
• Built-in anti-theft alarm system

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✔ Flood-Resistant & Reliable Operation

• Fully welded transformer tank structure
• Dual sealing for HV/LV cable entries
• Underground pit equipped with:
  • Water collection sump
  • Automatic drainage system with level sensor

👉 Ensures safe operation even in extreme weather conditions

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✔ Advanced Cooling System

• Tube-fin radiator design
• Corrugated pit structure for heat dissipation
• Natural ventilation via lighting box base
• Optional forced cooling system for overload conditions

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✔ Smart Monitoring & Remote Control

• Supports GPRS/communication interfaces
• Real-time monitoring of:
  • Lämpötila
  • Load
  • Power factor
• Enables remote diagnostics and reduced maintenance cost

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✔ Aesthetic & Corrosion-Resistant Design

• Underground unit coated with marine-grade anti-corrosion paint
• Lighting cabinet made of 304 stainless steel
• Concrete cover integrates with surrounding pavement

👉 Combines functionality with urban landscape design

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✔ Low Noise & Low Radiation

• Underground installation significantly reduces noise impact
• Metal pit structure provides effective electromagnetic shielding

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🔹 Operating Conditions

• Ambient temperature: -20°C to +40°C
• Altitude: ≤1000m (customized for higher altitudes)
• Relative humidity: up to 95%
• Wind pressure: ≤700Pa
• Installation tilt: ≤3°
• Seismic resistance: horizontal ≤3.0 m/s², vertical ≤1.5 m/s²

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🔹 Advantages Summary

• Underground space-saving design
• Highly safe and explosion-resistant
• Smart monitoring capability
• Strong flood resistance
• Urban-friendly aesthetic integration
• Low maintenance and long service life

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❓ FAQ

1️⃣ What is the main advantage of an underground prefabricated substation?

The biggest advantage is saving land space while improving urban aesthetics and safety.

👉 It reduces surface occupation and is ideal for crowded urban environments.

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2️⃣ Can the system operate in flooded conditions?

Yes. The system is designed with:

• Fully sealed transformer tank
• Dual sealing cable entries
• Automatic drainage system

👉 It can withstand temporary flooding conditions safely.

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3️⃣ Is remote monitoring available?

Yes, it supports smart monitoring systems, including:

• Lämpötilan seuranta
• Load monitoring
• Power factor tracking
• Fault alerts

👉 Enables intelligent operation and maintenance.

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4️⃣ What type of transformer is used inside?

It can be equipped with:

• S13 energy-efficient transformer
• SH15 amorphous alloy ultra-low loss transformer

👉 Depending on energy-saving requirements.