70mva electric arc furnace with serial reactor
Standard IEC 76, VDE 0532
Rated Power, nominal 70 MVA
Winding / oil temperature rise 55 / 50 °C
Operating Voltage / Frequency 33 kV / 50Hz
Rated lightning impulse withstand voltage 170 kV
Secondary Insulation Level, min. 4 kV
Impedance Voltage to be defined e.g. 6 up to 12 %
Output connection Closed delta Furnace Transformer Tap Changer
Tap Changer On-Load Number of taps 17 Secondary
voltage / current - Max. Sec Voltage 980 V - Ref. Sec. Voltage 550 V - Min. Sec. Voltage 400 V -
Max. current 61 kA Technical Description:
The operating voltage is set on the primary voltage side using a motor-operated onload tap changer. This tap changer is
installed inside the transformer tank in a separate compartment. Furnace Transformer Protective Facilities For the
transformer protection beside other, the following main equipment is foreseen: Buchholz protection Oil liquid level gage
with alarm contacts for the transformer main tank Water flow indicator with alarm contacts On Line Dissolved Gas Analyser.
The protection facilities feature either audible or visual signals. In the event of a fault, the transformer is immediately isolated
from the mains.
Furnace Transformer Cooling o Type of cooling OFWF o Cooler capacity 2 x100 % o Cooling water inlet temperature Max.
35 °C Technical Description: The windings of each ladle furnace transformer are cooled by the transformer oil. The
transformer will be provided with one-oil pumps and one double core heat exchanger. The oil-circulating pump conveys
the oil through an oil/water cooler, where the heat is transferred from the oil to the cooling water.
Serial Reactor
The transformer can be equipped with a serial reactor, which allows operating the furnace as high impedance furnace. The
reactor will be connected to the primary side of the transformer and will be equipped with off-load tap changer for optimization
of the different process stages. The reactor can be installed inside and outside of the ladle furnace transformer tank. Serial
reactor Main Data Type Air Insulated Phase Reactance 0 - 5 Ohm Tap changer On-load, Taps 5
Audited Supplier 
Audited Supplier 
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