6kV, 10kV and 35kV Dry-Type Power Transformer Manufacturer

YUGUANG 35kV and Below Resin Cast Dry-Type Transformer

YUGUANG resin casting dry-type transformers rated at 35kV and below are designed for modern power distribution systems requiring high safety, reliability, and environmental performance. Featuring high insulation strength, strong short-circuit withstand capability, and excellent fire and explosion protection, these transformers are maintenance-free and highly favored by users in industrial, commercial, and utility sectors.

With advanced natural air cooling technology, a single YUGUANG resin cast dry-type transformer can reach a capacity of up to 25,000 kVA. The voltage range covers 10kV to 35kV, with nearly 100 specifications and models available, providing flexible solutions for diverse power system requirements.

Transformer Capacity Range

YUGUANG specializes in medium- and large-capacity dry-type transformers tailored for industrial and utility-scale applications. The minimum standard capacity for dry-type transformers is 1000 kVA, ensuring reliable operation under continuous and high-load conditions.

We have extensive expertise in manufacturing high-capacity dry-type transformers above 5000 kVA, delivering customized solutions for complex and demanding power systems. While low-capacity transformers below 630 kVA, such as distribution transformers, can be manufactured, they are not supplied as standalone products and are only available as part of integrated solutions combined with medium- or large-capacity transformers.

Structural Features

Energy-Saving Performance

Through optimized electromagnetic design and high-quality materials, YUGUANG dry-type transformers achieve energy-saving performance superior to national standards, effectively reducing no-load and load losses and lowering operating costs.

Core Design

The transformer core is manufactured from high-grade grain-oriented silicon steel sheets and assembled using a fully inclined 45-degree step-lap joint structure. Elastic fixing devices are installed between the core and windings, and plate-type clamping structures with moderate tension are used to reduce vibration and noise.

The core surface is coated with black elastic resin paint and further encapsulated with resin, resulting in low no-load loss, low noise, excellent moisture resistance, and corrosion resistance. This design enables long-term reliable operation even in environments with up to 100% air humidity.

Transformer Windings

YUGUANG dry-type transformers utilize advanced winding technologies, including wire-wound cast resin and foil-wound structures, to ensure high electrical performance and mechanical strength.

In wire-wound cast resin transformers, both high-voltage and low-voltage windings are made of copper conductors with glass fiber reinforcement and thin insulation structures. The windings are vacuum resin cast and solidified following precise temperature-controlled curing curves. The sectional cylindrical winding structure improves electric field distribution, reduces inter-layer voltage stress, and significantly enhances impulse withstand capability.

Axial air ducts are integrated into both HV and LV windings, greatly improving heat dissipation efficiency and effectively reducing hot-spot temperature rise, thereby increasing the rated capacity and operational reliability.

For foil-wound dry-type transformers, the low-voltage coil is manufactured using specialized foil winding machines. The foil conductors are wound with DMD prepreg insulation to ensure tight winding, excellent insulation coordination, and high mechanical strength. Reinforced support plates between the LV coil and the core enhance short-circuit withstand capability.

The HV coil adopts a resin pouring process without surface painting, simplifying the manufacturing process, reducing environmental pollution, improving product appearance, and achieving cost efficiency.

Appearance and Cooling System

YUGUANG dry-type transformers feature a compact clamp structure with a clean, modern appearance. The inter-phase connections of the high-voltage coils are shielded for enhanced safety, and tap changers are protected by specially designed rubber stoppers to ensure secure and reliable operation.

The air cooling system uses low-noise, high-efficiency fans sourced from well-known manufacturers, delivering strong airflow, stable performance, and reduced acoustic impact.

Advantages of YUGUANG Dry-Type Transformers

YUGUANG dry-type transformers provide high impulse withstand capability due to epoxy resin and glass fiber composite insulation structures, with tensile strength reaching 600–700 MPa. The similar thermal expansion coefficients of copper conductors and composite insulation effectively prevent cracking, resulting in excellent short-circuit resistance.

The transformers offer outstanding moisture and corrosion resistance, enabling normal operation in environments with 100% humidity without the need for pre-drying before commissioning.

Optimized magnetic flux density and core clamping design allow noise levels to be controlled at approximately 53 dB, while maintaining low losses and low partial discharge levels.

Equipped with temperature monitoring, protection control systems, and forced air cooling options, YUGUANG dry-type transformers ensure safe, stable operation and meet the requirements of unattended substations.

With a completely dry structure free from insulating oil or gas, YUGUANG dry-type transformers eliminate the risk of leakage and environmental pollution. The epoxy resin insulation is self-extinguishing, does not support combustion, and releases toxic substances far below OSHA limits, making it an environmentally friendly and safe power distribution solution.