In-Depth Analysis of 10–35 kV Cast-Resin Dry-Type Transformers: Safety, Performance, and Reliability

Overview of 10–35 kV Cast-Resin Dry-Type Transformers

In medium- and high-voltage distribution systems, 10–35 kV cast-resin dry-type transformers are recognized for their safety, environmental protection, and stable operation. They are widely applied in urban power grids, commercial complexes, industrial facilities, and rail transit due to their excellent insulation performance and adaptability to harsh environments. Compared with traditional oil-immersed transformers, cast-resin dry-type designs provide superior moisture resistance, short-circuit withstand capability, and fire safety.

Structural Features of 10–35 kV Cast-Resin Dry-Type Transformers

Epoxy Resin Cast High-Voltage Coil

The high-voltage coil is integrally cast using epoxy resin, forming a solid insulation structure with high mechanical strength. This process eliminates internal air gaps, ensures low partial discharge, and provides strong crack resistance. The sealed resin structure is moisture-proof, dust-proof, and pollution-resistant, enabling both indoor and outdoor installation.

Low-Voltage Coil Structure

The low-voltage coil commonly adopts copper foil or foil-wound structures, which ensure uniform mechanical stress distribution. This significantly enhances the transformer’s ability to withstand short-circuit forces and improves long-term operational reliability.

Cooling System

Cast-resin dry-type transformers support two cooling methods. AN natural air cooling meets standard operating demands, while AF forced air cooling increases the rated capacity by 20%–40% when active, ideal for high-load applications.

Safety Performance Advantages

Fire and Explosion Resistance

The epoxy resin insulation system is flame-retardant and eliminates risks associated with oil spraying or combustion, ensuring safe operation even in critical environments.

Environmentally Friendly Operation

As an oil-free transformer, it avoids the risk of oil leakage and eliminates soil and groundwater contamination, making it suitable for environmentally sensitive locations.

Strong Environmental Resistance

The sealed coil structure provides excellent resistance to moisture, dust, and corrosive gases, ensuring stable performance in challenging industrial and coastal environments.

Performance Characteristics and Technical Advantages

High Mechanical Strength

After epoxy curing, the transformer windings achieve strong mechanical integrity, allowing them to withstand high short-circuit currents without deformation or failure.

High Energy Efficiency

Advanced core materials and optimized electromagnetic design ensure low no-load loss and load loss, improving overall system efficiency.

Low-Noise Operation

The stable insulation system and precision manufacturing ensure quiet operation, with an expected service life exceeding 30 years.

Reliability Advantages

Maintenance-Free Operation

Unlike oil-immersed transformers, cast-resin dry-type units require no oil inspection or filtration, significantly reducing long-term maintenance costs and labor requirements.

Flexible Installation

The compact, safe design allows installation close to load centers, saving cable length and reducing power transmission losses.

Application Scenarios for 10–35 kV Cast-Resin Dry-Type Transformers

Critical Infrastructure

Suitable for data centers, airports, and subway systems where power continuity and fire safety are essential.

Industrial Environments

Ideal for chemical plants, metallurgical facilities, and shipyards with high levels of humidity, dust, or corrosive gas exposure.

New Energy Sector

Used as box-type step-up transformers in photovoltaic power plants and as wind turbine transformers in wind farms.

Key Selection Considerations for 10–35 kV Cast-Resin Dry-Type Transformers

When selecting cast-resin dry-type transformers, focus on parameters such as rated capacity (1000–31500 kVA), voltage level (10, 20, 35 kV), impedance, no-load and load loss values, insulation class (F/155°C or H/180°C), temperature control system configuration, protection class (IP00, IP20, IP23), and enclosure or cooling system requirements.

10–35 kV cast-resin dry-type transformers deliver outstanding safety, environmental resistance, mechanical strength, and operational reliability. As smart grids, data centers, and modern transportation systems continue to expand, the demand for these high-performance transformers will continue to grow. For customized designs, technical solutions, and engineering configurations, please contact us for professional one-stop support.