Everything You Need to Know About Transformer Dimensions

Standard Transformer Dimensions by Type and Power Rating

When selecting a transformer, you should know its size and where it is applied. Let us discuss several common types of transformers in their standard sizes so that the reader can understand how each type fits into different spaces and tasks.

Physical Sizes of Transformers 

Three-phase, pad-mounted distribution transformers with separable insulated high-voltage connectors

Source: Canadian Standards Associations

Medium Voltage Transformer

• Voltage Range: Typically from 1kV to 35kV.
• Applications: Primarily used for medium-sized power distribution networks, electrical power users, power plants, and substations.
• Common Voltages: 6kV, 10kV, 20kV, 35kV, etc.
• Dimensions: 
• 500kVA: 1.5 m (L) x 0.9 m (W) x 1.2 m (H); weight around 1,800 kg
• 1,500 kVA: 2 m (L) x 1 m (W) x 1.5 m (H); weight around 3,800 kg
• 3,000 kVA: 2.2 m (L) x 1.2 m (W) x 1.8 m (H); weight around 5,200 kg

High Voltage Transformer
 

• Voltage Range: Typically from 35kV to 220kV.
• Applications: Used for power transmission over long distances, such as in high-voltage transmission lines, power stations, and substations.
• Common Voltages: 66kV, 110kV, 220kV, etc.
• Dimensions:
• 5,000 kVA: 4 m (L) x 2.5 m (W) x 3 m (H); weight around 20,000 kg.
• 10,000 kVA: 5 m (L) x 3 m (W) x 3.5 m (H); weight around 35,000 kg.
• 25,000 kVA: 6.5 m (L) x 4 m (W) x 4 m (H); weight around 65,000 kg.

Ultra High Voltage Transformer

• Voltage Range: This often exceeds 220kV; however, it may be as high as 1000kV.
• Applications: Transmission of the power over long distance in ultra high voltage transmission, reducing power losses while in transmission.
• Common voltages: 330kV, 500kV, 750kv, 1000kV, etc.
• Dimensions:
• 500,000 kVA: Approximately 8 m (L) x 4.5 m (W) x 5 m (H); weight around 280,000 kg.
• 1,000,000 kVA: Approximately 12 m (L) x 6 m (W) x 6 m (H); weight around 450,000 kg.
• 1,500,000 kVA: Approximately 15 m (L) x 7.5 m (W) x 7 m (H); weight around 700,000 kg.

See transformer types for your needs.

Key Components of Transformer Dimensions

Every transformer part is designed to a certain dimension that impacts the transformer's performance. If you know the main parts of transformer dimensions, you can understand why transformers are built this way and why specific dimensions are required, especially in industrial applications.

Core Dimensions

The core is the heart of the transformer. It is metallic and helps transform high voltage to low voltage or vice versa. The size of the core is directly proportional to the amount of electricity that a transformer can handle. Generally, transformer cores are relatively more important for higher voltage transformation, which in most cases means they are sturdier and more effective.

The transformer core cannot be too small since that would limit the maximum power that can be allowed in the transformer and make it less efficient. Again, if the core were too big, the transformer would be too heavy and occupy much space. Thus, its dimensions are the main trade-off between performance and space.

Winding Dimensions

The coils of wire wrap around the core. Their size and thickness determine whether the transformer has to bear higher or lower currents.

Larger windings force the transformer to carry larger currents but tend to increase heat dissipation. Thin or small windings will heat up and deteriorate the transformer's performance or even destroy it.

Every transformer capacity should have appropriate windings of the right thickness and material. High-capacity transformers, such as those in huge factories, require thicker windings to carry large volumes of power while cooling down safely.

Tank Dimensions

The outer casing is referred to as the tank, which protects the inner parts of the transformer and holds the cooling oil or air. The size of the tank will depend on the transformer's power rating. In larger industrial transformers, a larger tank is necessary to accommodate the core and windings safely and provide room for cooling.

The high-power transformers are quite larger and heavier, which would make them even better protected. Industrial transformers need enough space in the tank, especially for proper oil or air cooling under very hot working conditions, if they are to possess long-lasting durability.

Cooling System Dimensions

An important part of the industrial transformer's usage is its cooling system, which allows it to manage the loads on high power and their heat. Size, in general, within the cooling system mostly relates to radiators or fans and circulation systems in the oil. This is essentially determining the total size of the transformer.

 A certain size must correspond to the transformer's capacity so that no overheating will occur.

• Radiator Size Requirements: Radiators work like heat exchangers in the case of a transformer. The sizes would depend on the transformer power rating. The height for medium-power transformers is 4-6 feet. In high power, the radiator might be around 10 feet in height, and in some transformers, it extends several feet more to widen for proper heat dissipation. Larger radiators provide ample cooling to the system, but it will be rather significant additions to the transformer's footprint.
• Fan Size Requirements: Fans are added to a transformer to enhance cooling radiator capacity. Transformers as small as 1 foot by 2 feet may employ fans that are up to 4 feet in width for cooling wider areas of the radiator where a high-power transformer requires fans. Fans will further increase the width and length when attached on either the top sides of the setup.
• Oil Circulation System Size Requirements: High-capacity transformer oil circulation systems carry heat away from the core and windings; pumps, piping, and oil tanks may be included. Low-to-medium-capacity transformers only require simple oil-flow channels, while larger types need external tanks and pumps that can protrude feet in every direction and add a few pounds in weight plus volume to the unit.

It is very important to have the appropriate-sized cooling system to ensure that the transformer is safe and efficient. Cooling components should be greater and stronger in high-capacity transformers since less cooling can cause overheating and, thus, system breakdown.

Determining the Right Transformer Dimensions for Your Needs

Proper transformer sizing requires the consideration of what power the transformer must serve, where it will be, and how it is supposed to be used. Here are the simple steps and important things to consider:

Calculate Dimensions

Given the Load, Determine the power load that your transformer must feed. The load rating is usually a Power Capacity rating in kilovolt-amps (kVA) or mega-volt-amps (MVA).

Higher load ratings mean the transformer will need larger core and winding sizes and a more extensive cooling system. So, if your site has high power demands, you’ll need a bigger transformer with ample room for cooling systems like radiators and fans.

Consider Location and Space

Identify the location to which you are moving the transformer and the space you will have available. Indoor transformers are usually less weatherproof than outdoor transformers but would generally take more space because of ventilation. For most industries, clearances of 3-5 feet are used when installing transformers for easier access and safer people. 

Match Dimensions to Industry Standards

Transformer dimensions need to meet industry standards for safety and efficiency. Two prominent standards for dimensioning in the world of transformers are the International Electrotechnical Commission (IEC) and the American National Standards Institute (ANSI).

IEC standards are widely applied worldwide and make detailed recommendations for core size, cooling space, and safety clearances. ANSI standards, commonly followed in North America, require size, grounding, and installation spaces for different types of transformers.

​​​​​​​​​​​​​​More resource: 

Pad Mounted Transformer CSA C227.4 National Standard of Canada

CSA C88 Standard For Power Transformers

CSA C802 For Minimum Efficiency Values For Power Transformers

CSA C227.3 For Single Phase Pad Mounted Distribution Transformer

Three Phase Live Front Pad Mounted Transformers Under CSA C227.5

Follow Space Allocation Guidelines

To ensure your transformer fits safely and functions well, follow the space guidelines given by IEC or ANSI. For example, if the IEC standard suggests a minimum clearance for cooling or safety, you’ll want to ensure your transformer’s surroundings allow for this space. Without proper spacing, transformers may overheat, especially if cooling parts like radiators and fans don’t have enough room to work effectively.

All these steps will help you choose the right size transformer that suits your needs, is appropriate for space, meets power demands, and adheres to safety rules.

Conclusion

Choosing the right transformer dimensions size is key for safety, performance, and efficiency in industrial settings. By understanding your load requirements, space constraints, and industry standards (like IEC or ANSI), you can select a transformer that meets your facility’s needs. Cooling, safety clearances, and core and winding dimensions all play a role in making the best choice.

Daelim offers transformer solutions tailored to these standards, ensuring quality and reliability. Ready to find the ideal transformer? Contact us for expert guidance and options built to meet your industry’s demands!