Hermetically sealed oil-filled transformers for outdoor power distribution. S11, S13, S22, SBH15 series, 30-2500kVA, 10-33kV, IEC 60076 certified.
Oil-immersed distribution transformers use mineral oil or synthetic esters as both insulation medium and cooling fluid. The core and windings are submerged in oil within a sealed steel tank, providing excellent heat dissipation and electrical insulation. These transformers are the workhorse of outdoor distribution networks, mounted on poles, pads, or in ground-level substations. The oil absorbs heat from the windings and transfers it to the tank surface or radiators, enabling higher overload capacity than dry-type transformers. Ziyao Power manufactures S11, S13, S20, S22, SH15 and SBH15 series oil-immersed transformers. S13, S20 and S22 are silicon steel core low-loss oil-immersed transformer families for distribution projects. SH15 / SBH15 series uses non-crystalline metal core technology for enhanced no-load-loss reduction.
Where oil-immersed distribution transformers are used in real-world power infrastructure projects.
Single-phase and three-phase transformers mounted on utility poles for rural electrification and residential distribution.
Ground-level enclosed transformers for commercial and residential developments, with MV switchgear integration.
Main step-down transformers for factories and processing plants, installed in outdoor switchyards.
Grid connection transformers for solar farms and wind parks, with special design for renewable profiles.
Robust transformers for surface mining operations with dust and vibration resistance.
Explore our range of oil-immersed distribution transformers for various voltage levels and applications.
Capacity: 30-2500kVA
Voltage: 10/11kV
Capacity: 30-2500kVA
Voltage: 10/11kV
Capacity: 30-2500kVA
Voltage: 10/11kV
Capacity: 30-2500kVA
Voltage: 10/11kV
Compare specifications across different product series.
| Feature | S11-M | S13-M | S22-M | SBH15 |
|---|---|---|---|---|
| Core Material | Silicon Steel | Silicon Steel | Silicon Steel | Amorphous Metal |
| No-Load Loss | Standard | Lower | Premium low loss | 70% Lower |
| Fluid Type | Mineral Oil | Mineral Oil | Mineral Oil | Synthetic Ester |
| Fire Point | 140°C | 140°C | 140°C | 300°C+ |
| Environmental | Standard | Standard | Standard | Biodegradable |
Real-world installations using our oil-immersed distribution transformers.
Technical guides and resources about oil-immersed distribution transformers.
Mineral oil is petroleum-based with fire point around 140°C. Synthetic ester is a manufactured fluid with fire point above 300°C, making it much safer. Synthetic ester is also biodegradable, reducing environmental impact if leakage occurs. However, synthetic ester costs 3-4x more than mineral oil.
Amorphous metal, also called metallic glass, has a disordered atomic structure that reduces magnetic domain switching losses. In ZY POWER product naming, this core technology belongs to SH15, SBH15 and SCBH15 families. Standard S-series oil-immersed transformer families use silicon steel cores with progressively lower loss designs.
Initial test at commissioning, then annually for the first 5 years. After that, every 2-3 years if results are normal. Oil tests include breakdown voltage, moisture content, acidity, and dissolved gas analysis (DGA) for incipient fault detection.