In-depth Analysis of the Causes of Burnout in Water-Cooled Cables of Submerged Arc Furnaces

In-depth Analysis of the Causes of Burnout in Water-Cooled Cables of Submerged Arc Furnaces

Water-cooled cables for submerged arc furnaces, as key power transmission carriers in high-current heating equipment, operate under extreme environments of strong magnetic fields, high temperatures, smoke, and high loads for extended periods. Once the cable burns out, it not only leads to production shutdowns and maintenance but may also cause safety accidents such as cooling water leaks.

The following is an in-depth analysis of the causes of burnout from four dimensions:

I. Defects in Cable Raw Materials and Processes

The quality of water-cooled cables depends not only on the outer rubber sheath but, more importantly, on their internal structure and welding process.

Conductor Material: Some manufacturers use recycled copper with high impurity content, resulting in high DC resistance and severe self-heating during operation.

Welding Process: The weld between the copper wire and the cable head is a high-risk area for failure. Poor brazing techniques (such as the presence of porosity or incomplete welds) can lead to excessive contact resistance and localized overheating.

Hose Selection: High-quality sheathed hoses should possess extremely high voltage resistance, high temperature resistance, and tear resistance. If inferior synthetic rubber is used, the hose is prone to hardening and cracking at high temperatures, losing its protective function.

II. Operational Failures of the Cooling Water System

This is a unique cause that distinguishes water-cooled cables from ordinary cables; "water cooling" failure is the direct cause of burnout.

Water Scale Formation: Excessive hardness of the cooling water leads to scale formation inside the cable, reducing the cross-sectional area for water flow and decreasing heat exchange efficiency.

Poor Circulation: Insufficient flow or unstable pressure in the cooling system causes vaporization inside the cable (airlock phenomenon). The copper wires cannot dissipate heat in time, causing rapid temperature rise and eventual melting.

Metal Hose Blockage: Impurities in the circulating water can easily clog the water passage holes at the cable ends, causing uncontrolled localized temperature rise.

III. Mechanical and Chemical Aging Caused by Long-Term Operation

Fatigue Wear: During the operation of the submerged arc furnace, the frequent raising and lowering of the electrodes and the effect of electromagnetic forces cause the cable to oscillate continuously, resulting in mechanical fatigue. Over time, the internal copper wires may break, and the excessive current carrying capacity of the remaining copper wires leads to a vicious cycle.

Environmental Corrosion: High-temperature radiation from the furnace roof, splashing slag, and acidic fumes corrode the rubber sheath, drastically reducing its insulation performance and even causing flashover to ground, resulting in the cable instantly burning out due to arcing.

IV. Installation and Operational Standards Issues

Insufficient Bending Radius: Excessive bending of the cable during installation (too small a radius) can compress the internal copper wires, damaging the cross-sectional area and increasing cooling water resistance.

Overload Operation: Blindly pursuing output by overloading the current can exceed the cable's design limits, causing excessive temperature rise.

Lack of Maintenance: Failure to regularly clean conductive dust from the cable surface and failure to promptly monitor the temperature and conductivity of the circulating water prevent the early detection of potential problems.

Summary and Recommendations

Preventing the burnout of water-cooled cables in submerged arc furnaces requires a three-pronged approach: source control, operational monitoring, and regular inspection.

Product Upgrade: Prioritize the use of high-quality cables employing oxygen-free copper stranded wire, one-piece molding welding technology, and special high-temperature resistant tubing.

Water Quality Monitoring: Establish a closed-loop circulating softened water system to strictly control the temperature difference between inlet and outlet water and implement water pressure alarms.

Regular Inspection: Infrared thermal imaging technology is introduced to regularly monitor the temperature rise of cable joints, and the internal copper wires of the cables are inspected for breakage during major overhauls.

Through scientific management and standardized operation, the service life of water-cooled cables can be effectively extended, ensuring the efficient and stable operation of the submerged arc furnace.