Production - FREKANS TRANSFORMATÖR ENERJİ YATIRIM A.Ş.

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Production Facilities

Coil Winding Workshop

It is a special area where winding machines specially designed for High Voltage and Low Voltage are located and where the coils of transformers are produced.

Assembly Workshop

This is the section where the assembly operations of transformer components such as coils, cores, covers and boilers are carried out.

Metal Processing Workshop

It is the area where the cutting, bending, processing and welding operations of the metal parts of transformers are carried out.

Oven and Oil Pressing Workshop

This is the section containing the vacuum furnace and oil pressing units where the drying and lubrication processes of transformers are carried out.

Dyehouse

It is the place where the cleaning and painting processes of the metal parts of transformers are carried out.

Oven and Oil Press

This is the section containing the vacuum furnace and oil pressing units where the drying and lubrication processes of transformers are carried out.

Testing Laboratory

It is the laboratory where the final stage tests of transformers are carried out and quality control processes are carried out.

Warehouse

An area where completed transformers are stored awaiting shipment.

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Production Stages

Design

Designs are realized through software developed in-house by our own license and experienced technical staff. Based on customer demands, our project team meticulously follows the process from the offer stage to the order and delivery process. Each stage of design and implementation is approved by the customer and progresses. Meticulous and realistic studies in the offer stage minimize errors in the production and design stages. Our design team obtains comprehensive information about the working environment and conditions and provides guidance so that the customer does not make the wrong choice.

Core

As a magnetic circuit element, the core is manufactured from high quality, oriented, cold rolled and low loss, both side insulated silica sheets. Based on design inputs, projects are created using sheets with 0.23 – 0.27 – 0.30 mm thickness and different properties. The project is cut, aligned and converted into a magnetic circuit in line with technical details. The winding carrying parts in the core are called "legs", while the parts connecting these legs from the top and bottom are called "yokes". The yoke part is compressed with a metal structure to prevent vibrations.

Winding

Distribution transformers consist of two main sections: Low Voltage (LV) shares and High Voltage (HV) shares. LV covers are generally wound with large cross-section conductors closest to the core, i.e. in the inner parts, for insulation purposes, to carry high current with low voltage. HV interruption is generally wound on the upper parts of the LV coil, i.e. on the outer side, using smaller cross-section conductors to carry low current with high voltage. In conductor selection, electrolyte copper and aluminum materials with high electrical conductivity and purity are preferred. For insulation, materials of increased density, high pressure level, high mechanical pressure and oil-resistant, European-origin moisture are used. Coil losses, overload resistance and cooling calculations are designed and winding operations continue in accordance with the project.

Cover - Boiler

Transformer covers are manufactured from high quality ST-37 and ST-52 steel materials. In accordance with the project, it is manufactured by adding terminal outlets, protection and monitoring equipment, expansion tank mounting points and lifting ears, if any. Depending on the magnitude of the current passing through the terminals, reinforcement is provided with antimagnetic sheet metal to prevent the inter-phase and/or phase-neutral current loops from overheating the cover sheet. Cover welds are carried out using the leak-proof welding technique and are made ready for assembly after leakage checks are carried out.

The transformer boiler is manufactured from high quality ST-37, ST-52 materials and the cooling group is made of radiator or elastic wave wall sheets. Wave wall and/or radiator sheets are used with a thickness of 1.2 mm or 2.5 mm. All equipment is carefully assembled in accordance with the project requirements. Boiler welds are made with a special sealed welding technique, as thin sheet metal is welded to thick sheet metal. Following the manufacture of the boiler, penetrating liquid is applied and pressure is applied. After leakage checks are carried out in a dark environment using black light, it is shipped to assembly.

Assembly

The coils are placed on the core legs. After the core yoke parts are aligned, the magnetic circuit is completed. At this stage, the coils are compressed with insulation wedges and core yoke irons and fixed in a way that they will withstand the calculated short-circuit forces. The core is physically brought together with the coils and mounted on the cover as conductive terminal outputs, thus creating the active section. The active section is made ready for assembly after the boiler insulation distances are tested before or after the drying process, depending on the process, and is directed to the oil filling procedure.

Oven and Oil Press

The insulation life of transformers is of critical importance in terms of their operating life, and therefore, removing moisture is a vital process. Transformers whose active components have been assembled are baked in high vacuum ovens at temperatures of 105-110 degrees, where heat distribution is provided homogeneously, and are dehumidified. Insulation tests are performed at the beginning and end of the baking process to keep the process under control.

After the baking process is completed, oil is pumped under high vacuum to transformers where the boiler is assembled. Generally, moisture-free mineral oils are preferred in order to increase insulation strength and provide resistance to temperature effects. In addition, vegetable or oils with special formulations for fire safety can also be used. In addition, oil levels are adjusted in transformers with expansion tanks, while special pressure settings are made in hermetic transformers to end the process.

Product Quality Control and Testing

Transformers are controlled with physical and electrical measurements at each stage of the production process and proceed to the next stage. It is not possible to complete the process without production quality control elements, measurement, control and approval. Possible problems and faults are detected and resolved at the earliest stages of the production process.

The tests and measurements applied at the semi-finished product stage are as follows:

> Dimension measurements
> Conversion ratio measurements
> Insulation resistance measurements
> DC resistance measurements
> Sealing controls

Routine tests of all transformers are applied after the production stages are completed and some of these tests are repeated, provided that they are reported, while others are performed for the first time. Transformers that successfully pass all tests can proceed to the next stage by receiving approval.

Among the routine tests applied for transformers:

> Measurement of winding resistance
> Measurement of voltage turn ratio and control of voltage vector phase shift
> Measurement of short-circuit impedance as well as load loss
> Measurement of no-load loss and current
> Dielectric routine tests
> Induced voltage test
> Applied voltage test
> Insulation resistance measurement

Paint

Covers and boilers are cleaned and dried with special chemicals before painting. In order to protect against rust, a durable primer with high adhesion is applied as the first coat. Following the application of primer paint, the boilers are subjected to a drying process. After the drying process is completed, 2 or 3 layers of special topcoat paint are applied to meet the paint thickness in accordance with customer demands. Topcoat paint is generally preferred with RAL 7033 or RAL 9600 color, but different color options can also be provided depending on customer request.