comprehensive solution for power quality management in the steel industry

China is the world’s largest steel producer with a huge production scale and a strong industrial base, which is the basic industry and pillar industry of the national economy. The green and healthy development of the steel industry is of great significance to the development of the national economy, and iron and steel smelting is one of the important working conditions. Due to the load characteristics of steel smelting, there will be some prominent power quality problems, mainly including the following aspects: (1) harmonic problem Power electronic equipment widely used in steel production, such as frequency converters, rectifiers, etc., will generate harmonic current into the power grid during the working process. Electric arc furnace, refining furnace and other steelmaking equipment will produce a lot of harmonics due to the nonlinear characteristics of the arc. Especially in the melting period of electric arc furnace, the current changes dramatically and the harmonic content is very high. (2) Voltage fluctuation and flicker problem The frequent start and stop of large equipment, which requires large current when starting up, will cause the grid voltage to drop instantaneously; And when it stops, it will make the grid voltage rise instantaneously. In the working process of steel making equipment such as electric arc furnace, the instability of electric arc will lead to current fluctuation, and then cause voltage fluctuation and flicker of power grid. (3) Three-phase unbalance problem In steel production, the three-phase characteristics of some production equipment are inconsistent, which will cause three-phase imbalance. These power quality problems can increase the heat of electrical equipment, reduce the service life of equipment, and interfere with communication systems and automated control systems. Harmonics will produce noise in the communication line and affect the quality of signal transmission. Increased transformer and line losses.