Special transformers are used in special applications in the industry and in the grid. They are produced in small numbers and they generally have to deal with overcurrents, overvoltages and reactive loads under severe conditions. This requires each of the following transformers to be particularly addressed. A longer design and production process is required for special transformers than standard type power transformers. Special transformers are regarded as the peak of transformer industry due to know-how, diligence and accuracy required by both design and production technology.
Furnace Transformers
Furnace transformers are used in iron and steel plants for melting metal. The metal in melting pots are melted with very high currents.
Additional measures should be taken in furnace transformers against these high currents, possible short circuits and overcurrents.
- Production capacity is up to 360MVA,36kV.
- Must endure against short circuits and overcurrents.
Furnace Reactors
They are used to improve operating regime of furnace transformers in iron and steel plants.
Measures should also be taken on furnace reactors against all kinds of overcurrent and voltage caused by furnace operation.
- Production capacity is up to 250 MVAr,36kV.
- Increases reactance of the system and also enables reactance regulation.
- Must endure against short circuits and overcurrents.
- Can be in the same tank if required.
Shunt Reactors
These special transformers are used for compensating capacitive load formed in power transmission lines at times of low load.
Therefore, they are rated according to their reactive powers. They increase energy quality and efficiency of the grid by preventing over voltages besides their duty of compensation.
- Production capacity is up to 350MVAr,550kV.
- Acts as inductive load on high voltage transmission lines.
Current Rectifier Transformers
These transformers are used for feeding systems with direct current requirements. Their main areas of use are purposes of electrolysis in metallurgy plants and railway lines.
There are different approaches in the design of current rectifier transformers according to high output voltage or high output current requirements. They are produced with different structures according to number of pulses.
- Production capacity is up to 60MVA, 36kV.
- Can be with Bridge Assembly or Star Point Reactor.
- It is produced in 6, 12 and 24 pulses.
Phase Shifter Transformers
They are used to determine energy flow direction at connection points of high voltage grids. They are used to obtain different phase angles than inputs by using special coil structures at outputs.
Power and voltage of these transformers are limited to the capacity of the initial switch. Furthermore, customer and grid requirements should be understood well due to their role in the grid.
- Production capacity is up to 600MVA 550kV.
- Available application types; Single Active, Multiple Active, Booster, Autotransformer.
- Phase Angle adjustment up to ±45°.
