Know About Distribution Transformers And Their Types

Distribution transformers are said to be both delivery transformers and isolation transformers. The primary purpose of these transformers is to reduce the electrical power supply from high voltage to the average voltage. 

There are many types of transformers in the power supply system like underground transformers, 3-phase transformers, single-phase transformers, pad-mounted transformers, and pole-mounted transformers.

These different types of transformers are available in various sizes along with isolating oil. The selection of transformers depends on the budget and needs of the customer. You can choose any one connection from four types of connections in a distribution transformer. The connections are star-delta, star-star, delta-star, delta-delta, zigzag or delta-zigzag.

These days, electrical power supply power plants find it difficult to locate a perfect area for constructing a distribution transformer. This difficulty is pervasive in urban areas, so to install transformer you need to consider all these below factors to choose a suitable place,

● Load core

● Potential and further growth

● Load

● Specifications of transformer

● Height

● Weight 

● Specifications on a Single pole or H pole etc.

Thus, considering the availability of area or space and power supplied, India’s Distribution transformer manufacturers can fit or install their transformer.

How is a Distribution Transformer constructed?

The construction of a delivery transformer is achieved for small-scale transformers. The main parts of the transformers are,

● Oil Tank

● Conservator

● Pressure Relief system 

● Oil Indicator

● Conservatory Tank

● Buchholz Relay

● Breather Machine

● Temperature Monitor

● Thermal Relays

● Radiator

● Bushing

Oil Tank

The purpose of the oil tank in the transformers is to soak the windings of the transformers. While filling the oil tank, there is a quick way to contact and enlarge the oil inside the transformer to increase or decrease the temperature of the oil in the transformer.


A conservator of the transformer is placed above the oil tank in the outer part of the transformer frame. With the help of a hose, the conservatory is attached to the main tank. 

Pressure Relief System

To avoid the explosion of the transformer during the rise in pressure, the transformer uses a pressure relief system to reduce the pressure inside it.

Oil Indicator 

The oil indicator is placed within the conservatory unit. This oil indicator helps to indicate the amount of oil present inside the oil tank.

Conservatory Tank and Buchholz Relay

While using a conservatory tank, they use the Buchholz relay to avoid the inappropriate loss in oil flow between the transformer and tank.

Breather Machine

The breather machine of the transformer makes silica gel a part of the machine to retain the moisture in the oil. But, silica gel changes its color from blue to pink, so it fails to absorb the moisture in the oil.

Temperature Monitor

From the name itself, it is evident that the temperature monitor measures the temperature of the oil in the tank. If the coil’s temperature increases to a certain extent, it halts the transformer without allowing it to do the further operation. 

Thermal Relays

To measure the temperature of the windings in a transformer, it makes use of thermal relays.


If the transformer gets heated up, there should be a cooling system to reduce the heat. Hence, the radiator helps to cool the transformer.


To connect the internal windings of the transformer, it makes use of the bushing that wants the help of external electrical networks.

Types of transformers based on necessity.

1. Single-phase Transformer

When there is no need for a three-phase power supply, they make use of Single-phase transformers. Distribution transformer manufacturers India install transformers in Suburban areas to make use of these transformers during any overhead delivery loads.

Hence, these types of transformers repair delivery loads. You can find These transformers in applications like light commercial loads, light commercial electricity, industrial lighting, etc. 

The vital thing to note of single-phase transformers is that their primary and secondary windings are single-phase windings. These transformers generally convert electrical energy into magnetic energy and vice-versa.

The voltage that we get as an output is called relative voltage, whereas the voltage found between the two wires but no voltage applied to the ground is known as safe voltage.

2. Three-phase transformer

The primary purpose of Three-phase transformers is to store electrical energy. It makes use of the primary distribution circuit to a minor distribution circuit to store energy. Three-phase transformers often transfer the electricity to the secondary distribution circuit. 

Hence, there occurs a reduction in the voltage from the primary distribution circuit. Depending upon the needs of the consumers, three-phase transformers reduce the voltage allowance for the primary circuit. 

When 3 single-phase transformers of the same capacity combine, it gives a single three-phase transformer. The basic principle of all the transformers is the principle of electromagnetic induction.

3. Pad-mounted Transformer

Wherever you see a locked steel cupboard in the electrical power plants, you can assure that those are pad-mounted transformers organized in a concrete pad and hence called pad-mounted transformers. If you don’t have ample space or area to install a transformer, you will see the transformers enclosed in a steel cupboard. 

These transformers help reduce the primary voltage to place the electricity lines on an overhead electricity grid for the customers. You can find Pad-mounted transformers in tall buildings or apartments for safety purposes due to the small area. It contains a constant fuse and switch. The power distribution can vary accordingly from 75 kVA to 5,000 kVA.

4. Pole-mounted transformer

Wherever you see an electrical utility pole, then you can assure that pole-mounted transformers are mounted in these kinds of poles. These transformers are placed at the top of the overhead cables. This transformer converts the voltage of high-level distribution to the power of low-level. Mostly Rural areas make use of pole-mounted transformers. 

The power distribution can vary accordingly from 16 kVA to 100 kVA. If you find buildings that have single poles, you can easily install pole-mounted transformers. Rural areas use pole-mounted transformers because it is durable and reliable in severe climates. It avoids water accumulation and does not corrode.


Thus, in this article, we have seen the distribution transformers and their types. Without transformers, it is difficult for industrial sectors to run their equipment. Hence, Distribution transformers Manufacturers India fulfill many purposes by offering the best quality transformers. 

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