During the operation of the medium-frequency iron melting induction furnace, a large number of high-order harmonics will be generated. These harmonics will enter the power grid along the power line, causing interference and burning of other electrical equipment using the same power grid. In addition, it will also lead to a series of problems such as energy metering disorder and communication interruption. Therefore, it is imminent to control the harmonics of the furnace. The commonly used methods for harmonic control are MLAD-MFC medium frequency induction furnace special filter cabinet and MLAD-APF intermediate frequency induction furnace special active power harmonic filter.
The Harm of Harmonics in Medium Frequency Electric Furnace
During the operation of the intermediate frequency electric furnace, a large number of high-order harmonics will be generated. The main hazards of these harmonics are:
1. Electrical equipment
The high-order harmonics generated during the operation of the intermediate frequency melting iron induction furnace will reduce the efficiency of power transmission and utilization, resulting in overheating, vibration, noise, accelerated insulation aging, breakdown, failure, and even burning of electrical equipment, shorten the service life of electrical equipment;
2. Transformer
The high-order harmonics generated during the operation of the intermediate frequency iron melting induction furnace will reduce the usable capacity and utilization rate of the transformer, increase the noise of the transformer, increase the loss of the transformer itself, and reduce the service life of the transformer;
3. Reactive power compensation device
The high-order harmonics generated during the operation of the intermediate frequency iron melting induction furnace will cause the loss of the compensation capacitor in the reactive power compensation device to increase, overcurrent, overload, overheating, and accelerated aging of the insulating medium. In more serious cases, it will cause the compensation capacitor leaks, burst, or even burns out;
4. Electrical appliances
The high-order harmonics generated during the operation of the medium-frequency melting iron induction furnace will generate surge voltage or surge current, and even cause oscillation, causing electrical appliances to be burned;
5. Capacitance
The high-order harmonics generated during the operation of the intermediate frequency iron melting induction furnace will break down the capacitors in the point meter, causing the capacitors in the substation to burn out or trip;
6. Others
The high-order harmonics generated during the operation of the medium-frequency induction furnace will cause problems such as malfunction and refusal of relay protection devices and automatic devices, resulting in disordered power measurement and serious interference with communication equipment and electronic equipment.
Harmonic Control of Medium Frequency Iron Melting Induction Furnace
During the operation of the intermediate frequency electric furnace, not only integer harmonics but also fractional harmonics will be generated. The treatment of fractional harmonics is one of the difficult problems in the industry.
1. Special filter for intermediate frequency melting iron induction furnace
The special filter for MLAD-MFC intermediate frequency induction furnace is a passive filter. The corresponding filter branch needs to be specially made according to the actual situation on-site, in order to achieve a better harmonic control effect. MLAD-MFC special filter for intermediate frequency melting iron induction furnace has two kinds of high voltage and low voltage, which can not only filter the harmonics generated by the intermediate frequency electric furnace during operation but also effectively improve the power factor of the intermediate frequency electric furnace system, killing two birds with one stone;
2. Active filter for intermediate frequency induction furnace MLAD-APF special active filter for intermediate frequency electric furnace will detect the high-order harmonics generated during the operation of intermediate frequency electric furnace in real-time, and actively generate currents of equal magnitude and opposite direction to offset the harmonics generated by intermediate frequency electric furnace during operation, so, the filtering is more thorough, but the cost is higher.
