200 kVA 33kV Oil Immersed Power Transformer with Dyn11 Connection for Distribution Networks

The Oil Immersed Power Transformer model S-200/33-0.415 is a three-phase electrical device designed for voltage step-down in medium-voltage distribution networks. With a rated capacity of 200 kVA and a voltage rating of 33 kV / 0.415 kV (tapping range ±2*2.5%), this transformer is well-suited for light industrial facilities, commercial complexes, and rural electrification projects.

The transformer adopts Dyn11 connection group, where the high-voltage side is star-connected (Y) with neutral point not directly grounded, the low-voltage side is delta-connected (d), and the phase displacement is 30° (11 o'clock position). This configuration provides stable phase-to-phase voltage and effectively suppresses third harmonic currents.

Built for reliability and efficiency, this oil-immersed distribution transformer helps maintain stable power flow, reduce energy losses, and support balanced load distribution across electrical grids and substations.

This transformer adopts the ONAN (Oil Natural Air Natural) cooling method. Heat generated by the core and windings is absorbed by the insulating oil, which circulates naturally within the tank. The heat then dissipates into the surrounding air through radiator fins or cooling surfaces.

This natural cooling process eliminates the need for additional equipment such as fans or pumps, keeping maintenance low and supporting a longer service life. It also contributes to the transformer's environmentally friendly operation.

High-quality insulating oil serves two critical roles inside the transformer:

• Electrical insulation - Prevents electrical breakdown between live parts
• Heat removal - Transfers heat away from windings and core to maintain thermal stability

The oil also protects internal components from moisture and contaminants, enhancing the transformer's durability and reliability in various operating environments, including tropical and dusty conditions common in Africa and Southeast Asia.

This transformer is manufactured in accordance with the IEC60076 international standard, which sets requirements for power transformer design, testing, and performance. Compliance ensures that the product meets stringent benchmarks for:

• Insulation and temperature rise
• Short-circuit strength
• Mechanical integrity and efficiency

For end users, this means confidence in safety, reliability, and operational performance.

The transformer features a compact and sturdy construction, allowing flexible placement in outdoor substations or indoor electrical rooms. Key maintenance-friendly features include:

• Accessible oil filling and draining ports
• Temperature monitoring devices
• Pressure relief systems

These design elements facilitate routine inspection and servicing, helping to reduce downtime and maintenance costs over the transformer's operational life.

This oil-immersed distribution transformer is suitable for a wide range of scenarios:

• Medium-voltage distribution networks - Provides stable power supply for light industrial parks, commercial centers, and rural electrification projects
• Renewable energy projects - Used in small-scale wind farms or solar power plants for voltage step-up or step-down
• Infrastructure development - Supports grid extension projects in developing regions, particularly where 415V low-voltage systems are standard (e.g., Kenya, Nigeria, Philippines, and other markets across Africa and Southeast Asia)

The robust design and wooden pallet packaging also make the transformer easy to transport and install in remote or challenging locations.

The transformer model S-200/33-0.415 is manufactured in China and certified under GB standards. Customization is available to meet specific project requirements, including:

• Rated capacity adjustment
• Voltage combination changes
• Tapping range modifications
• Connection group (Dyn11 / Yyn0 / Yd11 as required)

Each transformer is carefully packaged on a wooden pallet to ensure safe delivery.

Comprehensive technical support and after-sales services are provided to ensure optimal performance throughout the product lifecycle. Services include:

• Installation and commissioning assistance
• Troubleshooting and diagnostic support
• On-site inspection and oil testing
• Thermal imaging and insulation resistance measurement
• Repair, refurbishment, and spare parts supply
• Customized training programs for customer personnel