Xi'an Zhibang
News Center
02
2024
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08
Measures to Solve Three-phase Power Unbalance in Electric Furnace Steelmaking
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Measures to Solve Three-phase Power Unbalance in Electric Furnace Steelmaking
When the electric furnace is working, even if the voltage and arc current of the three phases on the secondary side of the transformer are equal, the arc power of the three phases is not equal. This three-phase power imbalance is caused by the impedance imbalance of the three phases. The general short network three-phase conductor is planar, and the distance between the phases is equal. The short net length of the middle phase is shorter than that of the other two phases, and the inductance is also smaller than that of the other two phases, so the impedance is small. Thus, the arc power of the intermediate phase usually always exceeds that of the other two phases. The other two phases also cause different arc power due to different inductive reactance. The one with large arc power in the two phases is called "enhanced phase", and the one with small arc power is called "weakened phase"
phase ". The value of arc power enhancement and weakening of the enhanced phase and weakening phase is equal, that is, a part of the power is transferred from the weakened phase to the enhanced phase. This phenomenon is called "interphase power transfer". The larger the current, the more serious the imbalance of the three-phase arc power.
Three-phase arc power imbalance is very unfavorable to electric furnace steelmaking, which will cause uneven heating of the molten pool and serious damage to the local furnace wall, thus reducing the life of the furnace lining and directly affecting the productivity of the electric furnace. In order to reduce the adverse consequences of three-phase power imbalance, there are four measures:
1, as far as possible to make the short network conductor symmetrical arrangement, the short network from the original plane layout to equilateral triangle layout or improve the plane layout.
2. The electrode near the furnace door is arranged as the enhanced phase, and the electrode on the side of the steel inlet and outlet is the weakened phase.
3. Move the intermediate phase electrode to the center of the furnace by 10-20cm. In addition, in order to improve the life of the furnace lining, an unbalanced furnace lining structure can also be used, high-quality refractory materials are used in the hot spot area, and general refractory materials are used in the non-hot spot area.
4. The traditional short network line is a single-wire cloth method, and the double-wire cloth method of cross-arrangement of round-trip current should be implemented as far as possible.