20-35kV Epoxy Dry-Type Transformer
This 20-35kV epoxy resin dry-type transformer provides reliable, safe, and energy-efficient power distribution for critical infrastructure. Designed with flame-retardant materials and compact structure, it is ideal for industrial, commercial, and transportation applications requiring minimal maintenance.
20 – 35kV Epoxy Dry-Type Transformer Overview
The 20 – 35kV epoxy dry transformer is a medium-voltage electrical power solution designed for safe operation as either a primary or secondary electrical power source. These types of transformers are typically used in indoor and outdoor installations that need special safety precautions. This particular product uses advanced epoxy resin encapsulation technology. By using this method of encapsulation, the 20 – 35kV epoxy transformer is able to provide superior insulation and moisture resistance while being thermally stable without requiring oil (thereby eliminating the possibility of fires and/or liquid leaks). The 20 – 35kV dry epoxy transformer complies with the IEC 60076-11 certification as a flame-retardant and non-toxic product, making it ideal for extremely densely populated locations (e.g., hospitals, subways, etc.), and/or sites that require strict safety regulations (e.g., industrial plants).
With high-quality performance, low no-load, and load-loss features, this transformer complies with EU Code of Conduct Tier 2 requirements for efficiency, reducing the long-term energy cost of operation. Its compact and lightweight design enables it to fit into space-constrained substations, making it suitable for a wide variety of medium-voltage electrical distribution projects.
- Epoxy (oil-free, moisture-resistant) insulation utilizing epoxy resin encapsulation (IP20/IP23).
- Rated primary voltage: twenty (20) kV, twenty-five (25) kV, thirty (30) kV, thirty-five (35) kV, with 0.4kV (secondary); ±2×2.5% or ±5% tapping (maximum).
- Standard-rated kVA capacities of five hundred (500) kVA to two thousand five hundred (2,500 kVA); customizable for ratings above two thousand five hundred (2,500 kVA).
- Flame-retardant and explosion-proof; suitable for indoor installations and compliant with IEC 60076-11 standards.
Benefits and Key Advantages of Epoxy Dry-Type Transformers
High Safety
Fire-resistant and explosion-proof — no flammable liquids, ideal for indoor, underground, and high-risk areas with many people.
Energy Efficiency
Low no-load and load-loss rates comply with EU CoC Tier 2 standards, reducing energy costs and carbon footprint.
Space Saving and Lightweight
Smaller footprint and lighter weight simplify handling, transporting, and installation in confined switchgear rooms.
Low Maintenance
No oil to monitor or replace — only periodic visual inspections and cleaning are required.
Environmental Adaptability
Withstands a variety of environmental conditions such as humidity, dust, and chemical exposure. Suitable for coastal, industrial, and high-humidity areas.
Quiet Operation
Optimized core and winding design minimizes noise levels to ≤65dB, suitable for hospitals, schools, and residential areas.
Where and How the Product is Used
Industrial and Mining Operations
Oil-free electricity distribution for power systems in factories, processing plants, and mining substations — safe and environmentally friendly.
Commercial and Institutional Use
Fire-safe and low-maintenance design suitable for hospitals, retail shopping centers, universities, and high-rise buildings.
Transportation Infrastructure
Flame-retardant materials and low-maintenance designs meet the needs of subways, railway stations, tunnels, and airports.
Renewable Energy
Utilized by wind and solar farms in collection substations, benefiting from the outdoor capability of dry-type system construction for operational reliability.
Technical Data & Specifications
Standard 20-35kV epoxy dry-type transformer parameters. Custom voltages, monitoring systems, and protection levels available on request. Full dry type transformer specification sheets provided with quotation.
| Parameter | Specification |
|---|---|
| Voltage Rating | 20kV, 25kV, 30kV, 35kV (customizable) |
| Power Rating | 500kVA – 2500kVA (standard models) |
| Frequency | 50Hz / 60Hz |
| Efficiency | ≥99% at rated load |
| Insulation Class | F / H (temperature rise ≤100K / 125K) |
| Cooling Method | AN (natural air) or AF (forced air) |
| Noise Level | ≤65dB (under full load) |
| Protection Level | IP20 / IP23 (customizable) |
| Temperature Monitoring | PT100 sensors (optional) |
| Impulse Withstand Voltage | 75kV–170kV (depending on voltage class) |
Capacity and Loss Data
| Rated Capacity (kVA) | High Voltage (kV) | Tap Range | Low Voltage (kV) | Connection | No-load Loss (W) | Load Loss (W) | No-load Current (%) | Impedance (%) |
|---|---|---|---|---|---|---|---|---|
| 50 | 20; 22; 24 | ±5% ±2×2.5% |
0.4 | Yyn0 Dyn11 | 340 | 1230 | 2.2 | 6 |
| 100 | Yyn0 Dyn11 | 540 | 1990 | 2.0 | 6 | |||
| 160 | Yyn0 Dyn11 | 675 | 2470 | 1.6 | 6 | |||
| 200 | Yyn0 Dyn11 | 740 | 2940 | 1.6 | 6 | |||
| 250 | Yyn0 Dyn11 | 840 | 3420 | 1.4 | 6 | |||
| 315 | Yyn0 Dyn11 | 970 | 4080 | 1.4 | 6 | |||
| 400 | Yyn0 Dyn11 | 1150 | 4840 | 1.2 | 6 | |||
| 500 | Yyn0 Dyn11 | 1350 | 5790 | 1.2 | 6 | |||
| 630 | Yyn0 Dyn11 | 1530 | 6840 | 1.0 | 6 | |||
| 800 | Yyn0 Dyn11 | 1750 | 8260 | 1.0 | 6 | |||
| 1000 | Yyn0 Dyn11 | 2070 | 9780 | 0.8 | 6 | |||
| 1250 | Yyn0 Dyn11 | 2380 | 11540 | 0.8 | 6 | |||
| 1600 | Yyn0 Dyn11 | 2790 | 13870 | 0.8 | 6 | |||
| 2000 | Yyn0 Dyn11 | 3240 | 16380 | 0.6 | 6 | |||
| 2500 | Yyn0 Dyn11 | 3870 | 19380 | 0.6 | 6 |
Contact us for complete dry type transformer PDF catalog, testing reports, and dimension drawings.
Why Purchase Our Epoxy Dry Type Transformers
Manufactured by Experts
As a specialized manufacturer of dry type transformers, we produce and thoroughly test each coil in-house to achieve a consistent standard of quality.
Guaranteed Performance
Every unit undergoes routine testing per IEC 60076-11: resistance, insulation, temperature rise and partial discharge.
Cost Competitive
The ability to supply cast resin dry type transformers directly eliminates project procurement costs.
Fast Lead Times
Shipping time for standard models is 4-6 weeks; custom configurations with varying levels of protection and accessories are available on a flexible basis.
Certification and Standards
IEC 60076-11 ISO 9001 EU CoC Tier 2 CE RoHS
Dry Type Transformer Manufacturers & Brand Comparison
There are many global manufacturers of dry type transformers, such as ABB, Siemens, Schneider Electric, Eaton, & Square D; while each of these manufacturers offers a variety of products in their catalogue, our 20-35kV epoxy dry type transformers meet or exceed compliance with IEC standards, while offering a competitively priced alternative and shorter lead times for project configured products. We offer utilities and EPCs around the globe with tailor-fit voltage ratios, protective enclosures, and thermal monitoring. We also provide customers access to factory personnel for support.
Buyer’s Guide
How this Epoxy Dry-Type Transformer Fits Your Project
EPCs, facilities managers, and OEMs need to select safe, oil-free transformers for medium voltage systems.
Project Applications
The flame-retardant and explosion-proof design of the dry-type transformer make it an excellent choice for indoor substations in high-rise buildings that require compliance with the building code. Hospitals and schools are excellent examples of where a low noise level and oil-free operation will allow the transformer to work well in sensitive environments. Subways and tunnels are commonly found in urban transport systems and rely on compact and maintenance-free transformers to provide reliable signalling and ventilation power.
Dry Type vs. Oil Type – When to Choose Dry
Epoxy dry-type transformers should be considered when application, safety, or limited access for maintenance is a concern. Dry-type transformers do not need oil for cooling, will not catch fire, and will not contribute to soil contamination; hence, they are suitable for use in urban areas and green building projects.
Installation & Maintenance
Ensure sufficient natural air cooling by providing the transformer with proper ventilation; if the transformer will experience peak loads on a frequent basis, forced-air fans can be used to assist with cooling. The IP23 enclosure protects against the entry of groundwater and windborne dust particles. Routine maintenance consists of checking the condition of the windings visually and cleaning the ventilating grilles. No oil samples or dielectric testing of the transformer will be necessary.
Frequently Asked Questions
What is a dry type transformer?
A dry type transformer uses air or resin for cooling and insulation instead of liquid. Epoxy cast resin dry-type transformers encapsulate windings in solid insulation, providing fire resistance and low maintenance.
What is the difference between oil and dry type transformers?
Oil type transformers use insulating oil for cooling and high voltage insulation, suited for outdoor high-power applications. Dry type transformers use air or solid resin, offering fire safety, easier indoor installation, and no oil leak risks.
What is the difference between a dry and a liquid-filled transformer?
Liquid-filled transformers rely on oil or synthetic fluid for cooling and insulation; dry transformers use air or resin. The dry type eliminates oil handling, reduces fire risk, and simplifies maintenance, but may require more ventilation.
How to tell if a transformer is dry type?
A dry type transformer has no liquid level gauge, drain valve, or conservator. Its enclosure typically has ventilation grilles and will be labeled as “dry type” or “cast resin.” If there is no oil maintenance requirement, it’s likely dry type.
