How to adjust the voltage of electric furnace transformer

The electric furnace transformer is one of the core equipments in the electric furnace steelmaking system. Its main function is to convert the high-voltage power supply into a low-voltage and high-current power supply suitable for electric furnace operation, so as to meet the demand for electric energy in the electric furnace smelting process. In the actual operation process, the voltage of electric furnace transformer needs to be adjusted according to different smelting stages and process requirements, so as to ensure the stability, safety and economy of electric furnace operation.

First, the purpose of voltage regulation of electric furnace transformer

The main purpose of voltage regulation of electric furnace transformer is to adjust the voltage supplied to the electric furnace by changing the transformation ratio, so as to control the arc length and current to meet the needs of electric energy in different smelting stages. For example, large current and low voltage are needed in the initial stage of melting; In the refining stage, higher voltage and more stable current may be needed. Through reasonable voltage regulation, the efficiency of electric energy utilization can be improved, the power consumption and electrode consumption can be reduced, and the service life of equipment can be prolonged.

Second, the common voltage regulation methods

1. On-Load Tap Changer, OLTC)

On-load voltage regulation is one of the most commonly used voltage regulation methods for electric furnace transformers. It can realize voltage regulation by switching different taps without cutting off the load. This method has a fast response speed, is suitable for frequently changing smelting conditions, and has a high degree of automation and adjustment accuracy.

2. Off-Circuit Tap Changer.

Non-excitation voltage regulation requires voltage regulation operation under the condition of power failure of transformer, which is usually used in occasions where load changes infrequently. Although the operation is complicated, it is simple in structure and low in cost, and it is often used in some electric furnace systems that do not require high adjustment speed.

3. Thyristor voltage regulation technology

In recent years, with the development of power electronics technology, thyristor controlled rectifier voltage regulation technology has also been applied to electric furnace power supply system. By controlling the conduction angle of the thyristor, the voltage can be adjusted stepless, which has the advantages of fast response, high control accuracy, energy saving and environmental protection.

Iii. Matters needing attention in voltage regulating operation

1. Reasonable selection of voltage gear according to smelting stage.
Different smelting stages correspond to different voltage requirements, so operators should be familiar with the process flow and scientifically choose the voltage regulating gear to avoid the adverse effects caused by too high or too low voltage.

2. Pay attention to the matching of current and voltage.
While adjusting the voltage, it is necessary to pay close attention to the current change to prevent the sudden change of current from causing equipment overload or tripping.

3. Regularly check the pressure regulating device.
Long-term operation of pressure regulating device is prone to problems such as poor contact and wear, so it should be maintained and tested regularly to ensure the stable and reliable operation of pressure regulating system.

4. Application of automatic control system
Modern electric furnaces are usually equipped with automatic control system to realize closed-loop regulation of voltage, current and power, and improve voltage regulation efficiency and stability of smelting process.

Fourth, summary

Voltage regulation operation of electric furnace transformer is an indispensable part of electric furnace steelmaking process. Reasonable voltage regulation can not only improve the utilization rate of electric energy, but also prolong the service life of equipment and improve production efficiency and safety. With the progress of automation and power electronics technology, the voltage regulation mode of electric furnace transformer is developing in a more intelligent and efficient direction. In practical application, it is necessary to scientifically select the voltage regulation mode according to the specific process requirements, and strengthen the equipment maintenance and management to ensure the efficient and stable operation of the electric furnace system.