6 MVA Three Phase Power Transformer-33/6.6 kV | South Africa 2024

Innovation drives excellence – we safeguard every watt of power with technology!

01 General

1.1 Project Description

The 6 MVA Oil-immersed distribution power transformer was delivered to South Africa in 2024. The rated power of the oil Immersed transformer is 6000 kVA with ONAN cooling, the primary voltage is 33 kV with ±2*3% tapping range (NLTC), the secondary voltage is 6.6 kV, they formed a vector group of Dyn11.

6MVA transformers are widely used in industry, mines, power plants and large-scale pumping stations, and can effectively provide stable power for large motors, injection molding machines, welding machines and other high-load equipment. In addition, its efficient and reliable performance and strong load adaptability make it play an important role in power transmission and distribution systems.

1.2 Technical Specification

6 MVA power transformer specification and data sheet

1.3 Drawings

6 MVA power transformer diagram drawing and size.

02 Manufacturing

2.1 Core

The full inclined step joint is adopted to improve the flux direction, eliminate the local flux saturation phenomenon at the joint of the iron core, reduce the no-load loss and no-load current of the iron core, and reduce the transformer noise. In order to enhance the ability to resist short circuit, a number of pressure nails are distributed around the pressure plate, and the upper and lower high and low pressure clips are connected by support beams, so that the iron core becomes a whole. In addition, the surface of the core column is coated with silicon steel sheet special end glue, so that the silicon steel sheet and the sheet are bonded together, and the iron core becomes one body after curing. High strength electrical laminated wood supports are used between the lower part of the body and the wall of the tank, making the lower part of the body safe and reliable positioning.

2.2 Winding

In continuous winding, the wires are arranged tightly and evenly, so that the electromagnetic field distribution is more balanced. This design not only reduces the local hot spots that may be generated in the winding, but also effectively reduces electromagnetic interference, thereby improving the overall efficiency and stability of the transformer. Especially in high frequency or high power applications, continuous winding can significantly reduce losses and improve the response speed and sensitivity of the transformer.

2.3 Tank

Engineered for a 6MVA rating, this transformer tank provides mechanical support for the core, contains the insulating oil, and facilitates effective heat dissipation through its corrugated or finned walls. It ensures complete protection of internal components from the environment.

2.4 Final Assembly

Core and Winding Assembly: Properly installing the windings onto the core and performing necessary insulation treatments as required by specifications. Active Part Assembly: Inserting the assembled core and windings into the oil tank, ensuring accuracy in installation and insulation requirements. Oil Treatment: Injecting insulating oil into the tank for insulating and cooling the active parts, while also checking the oil quality and level. Attachment Installation: Installing cooling devices, protective relays, instruments, and valves to ensure safe operation and functionality of the transformer.

03 Testing

1. Measurement of dissolved gasses in dielectric liquid from each separate oil compartment except diverter switch compartment
2. Measurement of Voltage Ratio and Check of Phase Displacement
3. Measurement of Winding Resistance
4. Measurement Of D.C Insulation Resistance Between Each Winding To Earth And Between Windings

5.Applied Voltage Test

6. Measurement of No-Load Loss and Current
7. Induced Voltage Test
8. Measurement of Short-circuit Impedance and Load Loss
9. Leak Testing With Pressure For Liquid-Immersed Transformers

04 Packing and Shipping

05 Site And Summary

In conclusion, oil-immersed distribution transformers, with their superior cooling performance and robust design, are an ideal choice for various power systems. They not only provide excellent electrical performance but also maintain efficiency and stability during prolonged operation. Whether in urban distribution networks or industrial parks, these transformers can meet your power needs and ensure a reliable energy supply. We are committed to providing you with the most suitable solutions through advanced technology and high-quality service. Thank you for your attention and trust in our oil-immersed distribution transformers; we look forward to collaborating with you to create a brighter future.