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Dry-Type Transformers: Meaning, Types, Applications, and Advantages

In electrical devices, several small components are integrated for the device’s smooth functioning. One such component which is widely used in electrical systems and devices is a transformer. In an electric circuit, a transformer helps in decreasing or increasing currents/voltages. There are different types of transformers available, amongst which the Dry Type Transformers are widely used in various utility, industrial as well as commercial applications as they offer a plethora of benefits – low cost, enhanced safety, and high efficiency. Moreover, the growing technological advancements in dry type transformers aim to make electrical devices even more efficient in the upcoming years.



What are Dry Type Transformers?

A dry type transformer is a motionless device, which uses temperature insulation systems that are eco-friendly. It does have rotating parts. Dry type transformers are also known as cast resin type transformers. They are used in various applications, including commercial, utility as well as industrial.

In contrast, the conventional liquid-type transformers largely depend on the materials such as oil or fire resilient liquid dielectric. Unlike conventional liquid transformers, dry type transformers need not be kept inside fire-resistant vaults or catch basins and release no toxic gases. Such transformers are safe and can be installed indoors, making the system competent.

A dry type transform is also known as ‘voltage changing,’ signifying that in this transformer, the air is cooled instead of cooling the liquid. The reason behind this is – the case in which the dry type transformer is kept, it has proper ventilation, and this ventilation cools the coils with the air present inside the case.


What Are the Uses of Dry Type Transformers?

Generally, dry type transformers are used in low and medium-voltage applications in electrical devices. Furthermore, they have aluminium or copper windings which are covered with varnish.


What are the Applications of Dry Type Transformers?

There is a wide scope of applications of dry type transformers. We’ve listed below a few common applications:

  • Industries such as gas, oil, and chemicals use dry type transformers
  • Environmentally sensitive water protection areas use dry type transformers
  • Underground as well as indoor substations widely use dry type transformers
  • Dry type transformers are also used in forest areas.


What are the Advantages of Dry Type Transformers?

  • As dry type transformers do not release toxic gases, they do not create any pollution and hence, are environmentally friendly.
  • Dry type transformers can be successfully used in damped and contaminated areas.
  • The installation process of dry type transformers is easy.
  • The low thermal properties and dielectric heating properties of dry type transformers enhance their durability.
  • Dry type transformers are safe for surroundings as well as people.
  • Dry type transformers have high resistance, helping devices manage short circuit currents.
  • Dry type transformers offer excellent performance and have low side clearance.
  • With the help of their high capacity, dry type transformers are capable of handling overloads.


What are Different Types of Dry-type transformers?


1. VPI (Vacuum Pressure Impregnated) Transformers

VPI transformers are typically used for commercial and industrial purposes. Such transformers are built from components that are capable of bearing high temperatures. Additionally, they have a moisture-resilient polyester sealant, which is applied using the vacuum pressure impregnation method.


2. VPE (Vacuum Pressure Encapsulated) Transformers

VPE transformers are quite similar to Vacuum Pressure Impregnated transformers. However, VPE transformers are developed with silicon-based resin instead of polyester, which develops a comparatively thicker varnish. It is resilient to moisture, high humidity, and salt, which makes it an ideal and good option for harsh temperatures. VPE transformers are widely used in applications which are vulnerable to chlorides, acids, and alkalis.


3. Open Wound Transformers

 These transformers are named open wound transformers because their manufacturing process follows the ‘dip and bake’ process. In this, the coils are first heated and are then dipped in significantly high-temperature varnish. Thereafter, they are baked.


4. Cast Coil Transformers

This type of dry transformer is reliable in harsh or severe environmental conditions and requires bare minimum maintenance. Cast coil transformers are usually found inside tunnels, buildings, offshore platforms,  production plants, nuclear plants, and mining services.

Be it industrial, commercial, or utility applications, dry type transformers are the electric systems’ integral part. Furthermore, technological advancements, along with the focus on replacing the traditional insulated systems, will increase the dry transformers’ demand and drive the growth of the dry transformer industry. However, before investing in one, consult an expert professional who can guide you to choose the most appropriate type of dry transformer for your specific application, helping you leverage maximum benefits.