Product Overview
The underground transformer, also known as a buried transformer or submersible distribution transformer, is a compact, fully sealed power distribution device specifically designed for installation in underground pits, vaults, or direct burial applications. This innovative solution addresses the growing demand for aesthetic urban environments by eliminating unsightly overhead lines and above-ground substations that occupy valuable city space.
The product features a stainless steel, fully sealed tank construction with IP68 protection rating, enabling continuous operation even when fully submerged in water. It integrates the transformer body, high-voltage load switch, and fuses within a single liquid-immersed enclosure, offering a space-saving, maintenance-free solution for modern urban power distribution networks.

Key Features
1. Fully Submersible & IP68 Protection
The stainless steel fully sealed tank structure provides IP68 ingress protection, capable of continuous operation when fully submerged in water. High-voltage and low-voltage terminations use fully insulated, fully shielded plug-in cable connectors with no live parts exposed. The unit withstands 24-hour immersion testing with no performance degradation.
2. Space-Saving & Aesthetically Pleasing
The design eliminates the need for above-ground substations, preserving valuable urban landscape and freeing up ground space for green belts, sidewalks, and commercial use. It can be integrated with advertising lightbox enclosures for dual-purpose installations, making it ideal for city centers, tourist attractions, and environmentally sensitive areas.
3. High Safety & Reliability
The high-voltage side is protected by a dual-fuse system combining a plug-in dual-sensitive fuse with temperature and current sensing, plus a backup current-limiting fuse. The fully insulated, fully sealed structure ensures personal safety with zero risk of accidental contact with live parts. The stainless steel tank features advanced anti-corrosion coating for long service life in harsh underground environments, and a built-in automatic drainage system with water level monitoring and alarm is also included.
4. Low Loss & Energy Efficient
The core is available in cold-rolled grain-oriented silicon steel or amorphous alloy materials, with the amorphous alloy core reducing no-load losses by seventy to eighty percent compared to conventional designs. The low-temperature rise design limits oil temperature rise to 50K, which is 10K below standard requirements, and superior heat dissipation is achieved through optimized oil flow and forced air ventilation when required.
5. Intelligent Monitoring & Remote Control
A built-in GPRS or GSM communication module enables remote real-time monitoring of output current, voltage, oil top temperature, pit temperature, power consumption, and water level. The system supports remote meter reading, prepayment, and multi-rate tariff management, with theft and tamper detection providing remote alarm notification.
6. Maintenance-Free Operation
The fully sealed structure eliminates routine maintenance and oil changes. No core lifting inspection or periodic oil testing is required. Installation is simplified with plug-in cable connectors and easy termination.

Technical Specifications
Rated Power: 30kVA to 1,600kVA (customizable)
HV Voltage: 6kV, 10kV, 10.5kV, 11kV (customizable)
LV Voltage: 0.4kV, 0.415kV, 0.433kV, 0.69kV
Vector Group: Dyn11, Yyn0 (customizable)
Tapping Range: ±5% or ±2×2.5% (customizable)
Frequency: 50Hz or 60Hz
Cooling Method: ONAN (Oil Natural Air Natural) with optional forced air ventilation
Tank Protection Rating: IP68 (fully submersible)
Tank Material: Corrosion-resistant stainless steel
Core Structure: Three-phase three-column or three-phase five-column structure
Temperature Rise Limits: Oil top 50K, Winding 55K (10K below standard requirements)
Protection System: Dual-fuse protection (plug-in fuse plus backup current-limiting fuse)

Applications
The underground transformer is widely used in urban power distribution for city centers, commercial districts, and residential communities. It is also ideal for infrastructure projects including highways, bridges, tunnels, parking lots, airports, and ports. Public spaces such as parks, green belts, tourist attractions, and pedestrian zones benefit from its aesthetic and space-saving design. Municipal projects like street lighting, traffic signal systems, and landscape lighting commonly utilize this transformer type. It is also suitable for construction sites requiring temporary power supply, as well as industrial facilities where above-ground space is limited.
Compliance Standards
IEC 60076 Series, GB 1094 Power Transformers, GB/T 6451 Technical Parameters and Requirements for Oil-Immersed Power Transformers, GB 20052-2020 Energy Efficiency Limits and Energy Efficiency Grades for Power Transformers, and JB/T 10217 Technical Requirements for Underground Transformers.

Why Choose Us
The space-saving design eliminates above-ground footprint and preserves valuable urban real estate. IP68 protection ensures trouble-free operation even in flooded conditions. Smart monitoring provides remote real-time monitoring, alarm, and control for peace of mind. Amorphous alloy options deliver up to eighty percent reduction in no-load losses for superior energy efficiency. With years of experience in underground transformer production, we offer professional manufacturing with full-process quality control and rigorous tank pressure and submersion testing. Customization services are available for capacity, voltage, and intelligent monitoring features. Comprehensive after-sales support includes technical assistance, installation guidance, and long-term maintenance services.