Voltage regulation method of arc furnace transformer

The electric arc furnace transformer is a special transformer for the power supply of electric arc furnaces for iron and steel smelting. Large capacity, messy structure and high skill requirements. Its secondary voltage is very low, generally between tens and hundreds of volts, and it can be adjusted in a larger range; the side current often reaches thousands to tens of thousands of amperes.

In addition, in iron and steel smelting, the smelting cycle requires high power, requiring the transformer to be overloaded 2 0% within 2 hours. During the steel-making process, the electrode of the furnace body is very likely to short-circuit due to the collapse of the furnace material. Therefore, the primary side of the electric arc furnace transformer should be connected to the current limiting reactor, otherwise it should have a larger electric furnace transformer.

Limit the impedance of the short circuit current.

Electric furnaces also require power transformers to regulate voltage. There are two methods for adjusting the voltage of an electric furnace transformer.

　　1. Direct voltage regulation method: on the original winding of the transformer, the tap is connected to the tap switch. Between the three phases of the primary side, △ -Y can also be used to realize the regulation of the secondary side voltage. △ -Y switching is a very economical method of voltage regulation. Without changing the number of primary turns, the secondary voltage can be reduced to the original 1 /. Because each phase winding has 9 taps, plus △ -Y changeover, a total of 2 × 9, that is, 1 8-level voltage can be obtained.

　　2. Direct voltage regulation method: The figure shows the direct voltage regulation method of series transformer. The main transformer 1 is a three-winding transformer (see multi-winding transformer).

　　1 The winding is a high-voltage winding, which is connected to the power grid;

　　2. The winding is a winding with a suction cup, a series transformer I connected in series with the original 4 winding through a distributor switch;

　　3, windings and secondary windings of series transformers {{1}} series to supply power to the furnace load. By changing the primary voltage of the series transformer II through the shunt switch, the output voltage of the windings {{2}}, {{1}} can be modified. After receiving {{2}} or {{1}} windings of the load, generally only 1 to 2 turns, usually made of copper or aluminum plate Of 8 shaped coils.