The 35kV S11 Series Oil-Immersed Transformer is a high-performance, medium-voltage distribution solution engineered for modern power grids. Designed for 33kV, 35kV, and 38.5kV networks, this series represents a significant advancement over the older S9 models, offering substantially lower no-load losses and reduced noise levels.

The "Full Encapsulated" (Hermetically Sealed) design ensures that the transformer oil never comes into contact with the atmosphere. This prevents moisture and oxygen from degrading the insulation oil, effectively making the unit maintenance-free for its entire service life. Whether for rural electrification, industrial plants, or urban substations, the S11 series provides a stable, energy-efficient link in the power distribution chain.

• High-Quality Silicon Steel Core: Utilizes cold-rolled grain-oriented (CRGO) silicon steel with a multi-step mitered joint structure. This minimizes magnetic flux leakage and reduces no-load losses by up to 30% compared to traditional designs.

• Maintenance-Free Hermetic Seal: The corrugated tank design acts as an expansion bellows, accommodating oil volume changes due to temperature fluctuations without the need for a conservator tank. This protects the oil from oxidation and acidity.

• Superior Coil Strength: Windings are crafted from high-purity oxygen-free copper. The high-voltage coils utilize a multi-layer cylindrical structure, while low-voltage coils use foil or spiral windings, providing exceptional mechanical strength to withstand short-circuit stresses.

• Advanced Vacuum Oil Filling: Every unit is filled under high-vacuum conditions to eliminate air bubbles within the windings, ensuring a high dielectric strength and preventing partial discharge.

• Corrosion-Resistant Finishing: The tank surface undergoes grit blasting and a multi-coat electrostatic spray process (C4/C5 rated), ensuring the unit survives harsh outdoor environments and heavy UV exposure.

1. Utility Power Grids: Ideal for rural and urban substations as a primary step-down transformer from 35kV transmission lines to 400V local distribution.

2. Industrial Heavyweight Plants: Providing dedicated power for mining sites, cement factories, and metallurgical facilities.

3. Renewable Energy Hubs: Acting as a step-up or distribution hub for commercial-scale solar farms and wind power installations.

4. Infrastructural Projects: Powering metropolitan railways, airports, and large-scale water treatment plants.

• Optimized Thermal Performance: The corrugated radiator fins are precisely calculated to provide maximum surface area for cooling, ensuring the transformer remains within safe temperature limits even at 100% continuous load.

• Low Noise Design: By optimizing the core clamping pressure and using specialized damping materials, our transformers operate at decibel levels significantly lower than IEC requirements.

• Custom Tap Changers: Available with Off-Circuit Tap Changers (OCTC) or On-Load Tap Changers (OLTC) for precise voltage regulation in unstable grid conditions.

• Comprehensive Protection: Standard fittings include a pressure relief valve, oil level gauge, and signal thermometer. Optional Buchholz relays can be integrated for enhanced gas-fault detection.

Q: Does this transformer require oil changes?

A: Because it is a hermetically sealed unit, the oil is not exposed to air. Under normal operating conditions, the oil will not degrade or oxidize, meaning no oil changes are required for the duration of its 20-30 year service life.

Q: Can this unit be used in 60Hz markets like the Philippines or Americas?

A: Yes. We can customize the electromagnetic design specifically for 60Hz operation to ensure the same efficiency and thermal performance as our standard 50Hz models.

Q: What is the benefit of the Dyn11 vector group?

A: The Dyn11 connection is superior for handling unbalanced loads and mitigating the effects of 3rd harmonics, making it the preferred choice for modern industrial and commercial distribution.

Fully sealed oil-immersed transtormer(S11-35KV)

The three-phase oil-immersed distribution transformer produced by our company adopts a new insulation structure to improve the short-circuit resistance. The core is made of high guality cold emulsion silicon steel sheet. The high voltage winding is made of high quality oxygen-free copper wire and adoptsmulti-layer cylinder structure.All fasteners are specially loose-proof. The product has the high efficiency,the low loss characteristic, may save the massive electricity consumption and the operation expense,the social benefit is remarkable,isthe national promotion high and new technology product.