To address the issue of low power factor in submerged arc furnaces, my country typically employs capacitive compensation, usually applied at the high-voltage side. However, high-voltage side compensation fails to resolve three-phase imbalance. Furthermore, since the inductive reactance of the short-network accounts for over 70% of the system's total reactance, high-voltage compensation does not effectively reduce short-network reactance or improve the short-network power factor; nor does it achieve the goal of increasing transformer output-its benefits are largely limited to the power supply utility.
Consequently, some facilities have adopted a dual-compensation approach-applying reactive power compensation at both high- and low-voltage levels-for new furnaces to resolve these issues. Compensation at the short-network end significantly improves the power factor and reduces energy consumption. Implementing on-site reactive power compensation to address the substantial reactive power consumption and phase imbalance on the furnace transformer's low-voltage short-network-while simultaneously boosting the power factor-is a technically reliable and mature solution with a favorable cost-benefit ratio. Compared to high-voltage compensation, on-site reactive power compensation on the low-voltage side offers unmatched advantages in improving power factor, mitigating harmonics, increasing production, and reducing energy consumption. However, the approach entails high costs and subjects equipment to harsh operating environments, significantly shortening its service life. Additionally, low-voltage short-network compensation can increase harmonic levels, necessitating measures to suppress 3rd- to 7th-order harmonics; this drives up initial investment, extends the payback period, and results in high ongoing maintenance costs and poor overall economic efficiency. Therefore, this method is generally suitable only for newly constructed furnaces.