Don’t Get Confuse in Distribution and Power Distribution Transformers

Posted by Hardik on May 18th, 2019

Both the units are different and have unique features

When heard of distribution transformer, it is possible that you have searched for power distribution transformer with a thought that both are the same things. However, distribution transformer manufacturers want to explain both the units and how both of them are different from each other.

A distribution transformer is a unit applied to the buildings to bring down or step down the voltage and current level of a transmission line to a safety level. Whereas, power transformer is a unit applied at various power stations to transmit and generate power electricity. This is the basic defining difference between distribution transformer and power transformer unit.

If you are looking for a unit that works in transmission network of higher voltages, you can bring power transformer at your site. However, for distribution network, distribution transformer works best. Power transformer manufacturers are providing the units in different ratings- 400 kV, 200 kV, 110 kV, 66 kV, and 33 kV. You can do the selection of power transformer on the basis of these ratings. Ratings for distribution transformer vary. Manufacturers are providing 11 kV, 6.6 kV, 3.3 kV, 440 kV, and 230 kV distribution transformers to the global clients.

Power transformers require proper installation space due to their large size as compared to distribution transformers. Manufacturers intend power transformers for maximum efficiency of 100%, while distribution transformers have 50-70% efficiency.   Manufacturers measure the efficiency of power transformer as the ratio of output to the input power. The efficiency of distribution transformer is measured as the ratio of output in kWh to the input in kWh of a transformer in 24 hours.

Power transformers are applied in generating stations and transmission substations, while distribution transformers are applied in distribution stations along with industrial and domestic purposes. When we talk about losses- in power transformers, copper and iron losses occur throughout the day; whereas in distribution transformers, iron losses occur for 24 hours and copper losses occur on the basis of load cycle.

The flux density in power transformer is higher as compared to distribution transformer. Power transformer is designed to step up and step down voltages, whereas distribution transformers are used as end-user connectivity. Also, load fluctuations in power transformers are higher as compared to distribution transformers.

Power transformers are generally of four types –

1. Auto transformers – these are smaller, light in weight, and inexpensive when compared with standard dual-winding transformers. These transformers don’t offer electrical isolation.
2. Polyphase transformer – These units need three-phase transformers to step up or down voltages. Polyphase transformers are designed mainly for grounding and suppression of harmonic currents.
3. Leakage transformers – These are commonly known as stray-field transformers that have higher leakage inductance than other units.
4. Resonant transformers – These units have single winding with a capacitor that functions as a tank/tuned circuit.

Distribution transformers manufacturers are making three models of their product-

1. Single phase distribution transformer
2. Two phase distribution transformer
3. Three phase distribution transformer