Overview
Fully Sealed Oil-immersed Transformers are designed to deliver stable, reliable power performance while eliminating the risk of moisture ingress and oil degradation. Their sealed-tank construction, advanced core materials, and robust winding structures make them ideal for demanding industrial environments requiring long service life and minimal maintenance.
Applications
Suited for industrial plants, mining operations, commercial facilities, and utility networks where continuous, reliable power is essential—especially in environments with temperature fluctuations or high contamination levels.
Design Highlights
These transformers feature high-grade grain-oriented silicon steel cores, oxygen-free copper windings, and reinforced mechanical structures. The corrugated tank design replaces the traditional conservator, enabling efficient thermal expansion and superior cooling without additional piping.
Operational Advantages
With strong overload capability, high corrosion resistance, and superior short-circuit strength, these transformers operate reliably under fluctuating loads and multi-shift schedules. Their sealed construction ensures zero contact with the atmosphere, increasing oil lifespan and reducing maintenance requirements.
Environmental & Safety Considerations
The compact, sealed tank minimizes oil leakage risks and uses non-toxic materials, ensuring enhanced environmental protection. Fire-resistant insulation and harmonic-reducing winding configurations contribute to safer and more efficient operation across all conditions.
Maintenance & Lifespan
Thanks to the fully sealed design, these transformers require minimal routine maintenance. Corrosion-proof materials, sealed insulation systems, and optimized cooling contribute to extended service life and reduced operational downtime.
Features
- Completely sealed from the atmosphere, preventing or slowing oil degradation and moisture ingress into the insulation, ensuring longer service life and reliable performance.
- Iron cores constructed from high-quality cold-rolled, grain-oriented (CGRO) silicon steel. Core limbs are coated with polyurethane varnish and cured, providing superior insulation, enhanced mechanical strength, and durability under extreme operating conditions.
- Windings made from oxygen-free copper (OFC) with optimized winding patterns provide excellent short-circuit resistance and ensure stable voltage regulation under varying load conditions.
- Effective mechanical support at the winding ends improves structural integrity, minimizing deformation under short-circuit or overload situations.
- Corrugated fins on the tank replace the traditional oil conservator, expanding and contracting with oil volume changes and serving as efficient cooling elements. This eliminates the need for additional oil piping while maintaining optimal operating temperature.
- Strong overload capacity, exceptional corrosion resistance, and high reliability make these transformers suitable for heavy-duty industrial and mining applications with low maintenance requirements.
- Environmentally friendly design using non-toxic materials, with minimal risk of oil leakage due to the fully sealed structure.
- Proven performance in multi-shift operations, ensuring continuous power supply even under fluctuating load conditions.
Amorphous Core Variation
- Core made from amorphous alloy reduces no-load losses by 75%–80% compared to traditional silicon steel cores, improving overall energy efficiency.
- Lower heat dissipation and reduced temperature rise enable prolonged operation under heavy load conditions without compromising reliability.
- Suitable for industrial and mining sites operating multi-shift schedules with load factors between 50%–80%, delivering consistent performance throughout.
- Low-voltage windings adopt a foil-winding structure, offering strong short-circuit resistance and enhanced thermal stability.
- Dyn11 connection group reduces harmonic impact on the power grid, improving overall power quality and ensuring stable voltage for sensitive industrial equipment.
- Designed for high safety, reliability, and long-term durability, with minimal maintenance costs and easy inspection procedures.
Specifications
- Voltage rating: Up to 33 kV
- Rated power capacity: 30 kVA to 2.5 MVA
- Rated frequency: 50 Hz
- Vector connections: Dyn11, Yyn0
- No-load taps: ±2.5%, ±5%
- Standards: AS 60076
Enclosures for Fully Sealed Oil-immersed Transformers
The stainless steel enclosure provides extra protection against environmental and operational hazards. IP20 enclosures prevent intrusion of solid objects larger than 12 mm, while IP23 enclosures prevent water ingress at angles less than 60°, making them suitable for outdoor installations. The fully sealed design reduces maintenance requirements and protects internal components from dust, moisture, and corrosion, ensuring long-term operational reliability.
