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Ladle Furnace Transformer Overview

Ladle furnace transformers

Ladle Furnace Transformer Overview

With the increase of cooperation between ladle furnace transformer and electric furnace manufacturers in developed countries, Hani Metallurgy and LF furnace matching transformers have changed.

Among them, the LF furnace less than 40t still uses the traditional type, and the transformer structure for the LF furnace greater than 40t.

After a lot of research and development, testing and market feedback, the standards for ladle furnace transformers are formed as follows:

With the requirements of energy saving and consumption reduction in the iron and steel industry, as the main equipment used in iron and steel smelting—transformers,

In order to cope with factors such as the reduction of power consumption per ton of steel,

Hani Metallurgy pursues the following four goals in transformer equipment and manufacturing

1.Transformers Can Save Energy Very Well

Namely no-load loss, no-load current, load loss.

Reduce the percentage of impedance voltage as much as possible, select the appropriate capacity on the commonly used capacity, use the existing high-quality raw materials,

and use advanced technologies such as small oil gaps to make the transformer truly energy-saving, and the performance level is consistent with the products of international developed countries.

2.The Transformer is Stable & Reliable, & Has Long Service Life

The product design technology of the new structure has to go through the test of operation and the verification of the type test, and the design life is not less than 30 years.

3.Have A Certain Overload Capacity

To ensure that the user is in excess of the nominal capacity, 20% of the load, the operating indicators are running properly.

4.Reduce The Maintenance Workload of Users

Make users no longer hang the core in long-term use, and the design maintenance-free time is not less than ten years.

The overhaul-free period is twenty years.

5.Selection of Transformer Material, Structure & Process

See the detailed analysis below.

Ladle Furnace Transformer Material, Structure & Process

There are mainly 6 parts: iron core, winding, body, fuel tank, final assembly and accessories.

1. Iron Core

Hani Metallurgy selects 30Q130 silicon steel sheets from WISCO or 30Z130 from Nippon Steel Co., Ltd.

These materials are basically the same as those used in developed countries.

A full miter seam sheet type is used in the structure.

The upper and lower clamps are connected by the pull-plate structure of low-magnetic steel plate, which has changed the previous square iron structure.

So that there are no holes on the iron core, the magnetic flux density of each section of the iron core is consistent, and there is no distortion.

Adopt German imported Georg shearing line, control shear burr <0.02mm (standard <0.05 is qualified product) per meter length tolerance <0.2mm>, thus increasing the lamination coefficient and reducing the gap between the seams,

It avoids local overheating of the iron core and reduces product noise, no-load loss and no-load current.

2.Winding

Use oxygen-free copper magnet wire material, control its ρ20℃<0.017241.

In addition, control the material and tightness of the paper wrap insulation.

The purpose is to make the coil have better axial and radial stability as much as possible.

The coil adopts small oil gap, inner and outer oil shield, guide cooling, and cardboard tube structure,

which makes the structure compact and the overload capacity and thermal stability ability are improved.

Losses have also decreased.

3.Body

All wood parts of the body are changed to laminated wood, which improves the rigidity of the lead frame.

The upper and lower pressing plates are made of cardboard crimping or epoxy resin forming parts.

Compared with iron pressing plates, the insulation distance of electrical conductors to ground is increased, and the “window height” size can be reduced.

The primary and secondary main insulation adopts imported cardboard, which increases the main insulation strength, and the multi-coil adopts a whole set, which improves the reliability of the product.

The drying of the device body adopts the vapor-phase drying equipment made in Norway, which is thoroughly dried without damaging the insulation, and has the function of washing the device body.

4.Fuel Tank

The folding plate type is adopted, the welding seam is minimized, the strength is increased, and the positive and negative pressure tests are carried out to ensure the reliability of the product sealing.

Use low-magnetic steel sheets or magnetic shields where appropriate to reduce additional losses on the box walls due to the magnetic field of the bus conductors.

This work has achieved very good results in anti-seepage and loss reduction.

5.Final Assembly

After the body is dry, the winding loosening is compressed by hydraulic equipment and has achieved good results.

The use of vacuum oil injection reduces the air bubbles in the product winding, reduces the partial discharge, and increases the product life.

The use of new anti-aging sealing materials has improved the original leakage problem.

6.Accessories

The main accessory water coolers are tube type or spiral plate type oil-water coolers, or distributed installation, or directly fixed on the mainframe of the transformer.

The on-load tap-changer is selected from imported ABB Company, MR Company or Changzheng No. 1 Factory.

In addition to the requirement of remote display, there is also a remote control interface.

The transformer oil is naphthenic anti-aging transformer oil produced by Karamay, and the protection of the oil is a fully enclosed structure (ie, the pressure relief valve is equipped with a diaphragm oil conservator structure).

For more information about Ladle furnace transformer, welcome to contactc us freely!

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