Transformer – Conventional OFT

Oil Filled Transformer from Arpan Power Projects is built to carry electricity from where it is generated to the homes, businesses and industries that use it. Our Conventional OFT range runs from 63 kVA to 10,000 kVA, in copper-wound and aluminium-wound versions, for indoor and outdoor installation. This page follows the path of power through the grid and then helps you make the five choices that decide which unit is right for your site.

Follow the Power: Where an Oil Filled Transformer Sits

Electricity leaves a generating station at a voltage chosen for efficient transmission over long distances. Along the way, transformers raise or lower that voltage. Near the end of the journey, a distribution transformer steps it down to a level that homes, shops and factories can use safely. An Oil Filled Transformer can serve at several of these points, from distribution networks to larger power applications, which is why a wide capacity range such as 63 kVA to 10,000 kVA is useful. You can read the basics in this overview of the transformer.

Why Oil? What the Liquid Does Inside

In an oil filled transformer, the core and windings sit in insulating oil. The oil does two jobs. It insulates the live parts from each other and from the tank, and it carries heat away from the windings to the tank walls and radiators, where it is released into the air. This simple arrangement has made the Oil Filled Transformer a long-serving choice for transmission and distribution, and it is why these units handle heavy loads reliably.

Five Choices That Decide Your Oil Filled Transformer

Choice 1, copper or aluminium winding. Copper-wound units conduct electricity very well and are generally compact and efficient, while aluminium-wound units are generally lighter and lower in cost. Both are available, so the decision depends on your budget and efficiency targets.

Choice 2, indoor or outdoor. An outdoor unit is built to face rain, sun and dust, while an indoor unit needs attention to ventilation and space in the room. Both are available.

Choice 3, sealed or non-sealed. A hermetically sealed type keeps the oil sealed away from outside air, while a non-sealed type lets the oil breathe through a breather. Both types are available.

Choice 4, tap changer. An off load circuit tap changer is adjusted only when the transformer is switched off and disconnected, which suits stable supply conditions. An on load tap changer adjusts the voltage while the transformer stays in service, which suits networks where voltage varies and supply cannot be interrupted.

Choice 5, pole-mounted or ground installation. Pole mounting is generally used for smaller distribution ratings, while larger units are installed on the ground. Both installation options are available.

Where an Oil Filled Transformer Is Used

Typical uses include power distribution to residential areas and commercial buildings, industrial plants and factories, utility substations and distribution networks, infrastructure and construction projects, and renewable energy projects that feed power into the grid. If you want a complete package with a transformer, ring main unit and LV panel in one enclosure, look at our Compact Sub Station.

Sizing Your Transformer in Three Steps

1. Add up your connected load and decide how much room for growth you want.
2. Decide the voltage levels on the primary and secondary side.
3. Pick the kVA rating from our range of 63 kVA to 10,000 kVA.

Send these details to Arpan Power Projects and we will recommend the winding, tap changer and installation type.

Why Choose Arpan Power Projects for Oil Filled Transformer

Arpan Power Projects supplies transformers and HT switchgear with practical technical guidance. As a Transformer Supplier in India, we help you pick the right rating and configuration and support you through to commissioning. A transformer works together with protection and switching, so you can also explore our Control & Relay Panels, our 11KV Outdoor VCB Supplier in India page, or the complete Transformer range.

Oil Filled Transformer: Frequently Asked Questions

Is an oil filled transformer the same as a distribution transformer?
A distribution transformer is defined by its job, which is stepping voltage down for end users. Oil filled describes how it is insulated and cooled. Many distribution transformers are oil filled, and our range also covers larger power applications.

Which capacities does your Oil Filled Transformer range cover?
We supply from 63 kVA up to 10,000 kVA, in copper-wound and aluminium-wound versions.

What is the difference between sealed and non-sealed types?
A hermetically sealed transformer keeps its oil sealed from outside air, while a non-sealed type lets the oil breathe through a breather. Both are available.

When should I choose an on load tap changer?
Choose it when your supply voltage varies and you cannot afford to switch the transformer off to adjust the tap. If conditions are stable, an off load circuit tap changer is usually enough.

Copper or aluminium wound, which should I buy?
Copper-wound units are generally compact and efficient, while aluminium-wound units are generally lighter and lower in cost. Tell us your budget and efficiency needs and we will help you decide.