Oil Power Transformers

GBE UK supplies oil power transformers up to 50 MVA with a voltage of 145kV (BIL650), with Off Circuit or On Load Tap Changer. The On Load Tap Changer can be either external or internal to the transformer tank. The oil power transformer is made according to constructive and design criteria to ensure the highest operational reliability and a great performance in the electrodynamic stress, as well as excellent isolation to avoid problems related to possible network overvoltages.

The magnetic core is made with high-permeability 45-degree cut steel sheets in the European or American step lap type. The pack tighteners of the magnetic sheets are sized appropriately to ensure the mechanical sealing, noise reduction, and any problem relating to the handling or stresses of the windings.

The MV and HV windings are made of a disc or with transposed cable conductors; they are made with horizontal or vertical winding machines by experienced staff in a controlled environment. 

The positioning of the coils and the gap between them and between the layers is performed according to the precise indications of the electrical design, as well as the type of conductor and its processing. The drying and pressing process of the windings before assembly is fundamental and is carried out in a furnace with dry air circulation, monitored and recorded temperatures. 

The power transformer can have two or more windings and can be fitted with a compensation winding.

What is an oil power transformer?

An oil power transformer is a large, liquid‑filled transformer where the magnetic core and windings are immersed in insulating oil; GBE supplies these machines up to 50 MVA and 145 kV, and they can include Off‑Circuit or On‑Load Tap Changers (either tank‑mounted or external) to manage voltage regulation on site.

How does an oil power transformer work?

It transfers electrical energy between windings via a laminated magnetic core while the oil provides dielectric insulation and cooling; GBE’s designs use high‑permeability, 45°‑cut steel in step‑lap cores, carefully tensioned sheet packs and precisely positioned disc or transposed‑cable windings, all dried and pressed under controlled conditions to withstand electrodynamic stresses and avoid overvoltage or partial‑discharge issues.

What are the benefits of an oil power transformer?

Oil cooling gives excellent thermal performance and overload capacity, while oil immersion improves dielectric strength and extends insulation life; GBE’s construction methods (core cutting, pack tighteners, winding techniques and monitored drying) reduce noise, improve mechanical sealing and ensure the transformer copes with handling and electrical stresses, delivering reliable long‑term service and efficient operation.

Where are oil power transformers used?

These units are specified for substations, power plants, large industrial sites and any application requiring high power, robust insulation and dependable voltage control; their flexibility (multiple windings, compensation windings and OLTC options) makes them suitable where precise regulation and heavy‑duty performance are required.