• Reduced mechanical stress: Due to the reduced current, the electromagnetic force is decreased, and the impact stress and vibration on mechanical equipment components are reduced. The short-circuit current impact on electrical equipment components is also alleviated.
• Lower power grid interference: It can reduce current fluctuations by 46% and voltage flicker by nearly 30%, thereby reducing the impact and interference on the power grid and reducing flicker.
• Lower consumption: The reduction in current leads to a decrease in power consumption and electrode consumption.
• High arc stability: Due to high reactance and low power factor, the arc stability is high.
• Reduced equipment vibration: It can reduce the tremor caused by the insufficient rigidity of the electrode lifting mechanism.

Parameters of High Impedance Electric Arc Furnace

1. Basic Rated Parameters (Classified by Mainstream Capacity)

Note: Compared with conventional electric arc furnaces, high-impedance furnaces feature more stable arcs and allow long-arc operation, resulting in higher transformer utilization efficiency and faster smelting rhythm.

2. Key Electrical Parameters (Critical Characteristics of High-Impedance Furnaces)

2.1 Short-Circuit Impedance and Series Reactance

• Short-circuit impedance of conventional EAF transformers: generally 10%～12%
• Short-circuit impedance of HIEAF transformers: increased to 16%～20%, and can reach 22% for extra-high-impedance designs
• Series reactor reactance on the primary side: 1.5 to 2 times the leakage reactance of the furnace transformer. The increased total circuit reactance effectively limits short-circuit impulse current and suppresses voltage flicker.

2.2 Rated Voltage Level

2.3 Rated Current and Short-Circuit Current

• Rated electrode operating current: increases with capacity, about 25～30kA for a 50t furnace and up to 40～50kA for a 100t furnace.
• Core advantage of high-impedance design: short-circuit impulse current can be reduced by 30%～40%, greatly mitigating impacts on the power grid, transformer and short network.

2.4 Power Factor

3. Electrode and Short Network Parameters

• Electrode Material: Ultra-High Power (UHP) graphite electrodes are widely adopted, featuring oxidation resistance, high temperature resistance and higher allowable current density.
• Electrode Diameter
  • 30t furnace: Φ350～400mm
  • 50t furnace: Φ450～500mm
  • 80～100t furnace: Φ550～600mm
  • 150t furnace: Φ650～700mm
  
  
• Electrode Consumption Index: Benefiting from long-arc operation and small current fluctuation, electrode consumption of HIEAF can be controlled at 1.2～1.8 kg/t steel, while that of conventional EAF is generally above 2.0 kg/t steel.
• Short Network Parameters: The short network adopts large-section water-cooled copper tubes or copper-aluminum composite conductors. Length is minimized and circuit resistance is reduced to lower active loss. For HIEAF, circuit reactance matching is prioritized over simple resistance reduction.

4. Structural and Process Operating Parameters

4.1 Furnace Structure

• Furnace Shell Material: High-strength boiler steel plates such as Q345, lined with refractory materials including magnesia-carbon bricks and alumina-magnesia-carbon bricks.
• Furnace Cover Type: Full water-cooled truss furnace cover, with high temperature resistance, long service life and adaptability to high-power long-arc working conditions.
• Tilt Angle: Rated tapping tilt angle is 45°～50°, hydraulically driven with adjustable tilting speed.

4.2 Oxygen Supply and Carbon Injection System

• Oxygen Supply Mode: Combined-flow oxygen lance and water-cooled oxygen lance, with oxygen pressure of 0.8～1.2MPa. Oxygen flow increases with capacity, reaching 3000～4000Nm³/h for a 100t furnace.
• Carbon Injection System: Used for foaming slag generation and submerged arc operation. Coordinated with foaming slag, HIEAF can further increase operating voltage and reduce power grid fluctuation.

4.3 Smelting Cycle and Temperature

• All-scrap smelting cycle: For 50～100t HIEAF, power-on smelting time is 45～60min/heat. Including tapping, patching and charging, the total cycle is 60～80min.
• Tapping Temperature: Depending on steel grades, 1600～1680℃, with higher temperatures for special steels such as stainless steel.

5. Energy Consumption and Environmental Protection Indicators

5.1 Power Consumption Index

• All cold scrap smelting: 380～420 kWh/t steel
• With hot metal addition or hot-charged scrap: can be reduced to 320～360 kWh/t steel

5.2 Power Grid Interference Indicators

• Voltage Flicker (Pst): Reduced by 25%～35% compared with conventional furnaces, making it easier to meet power grid standards for harmonic and flicker limits.
• Harmonic Suppression: Equipped with reactive power compensation and filtering devices, it can comply with the harmonic limits specified in GB/T 14549.