Study on the Application of Modified Sn-Based Solder in Cable Intermediate Joints.

Area of Science:

• Materials Science
• Electrical Engineering
• Power Systems

Background:

• Increasing demand for underground cables necessitates high-quality intermediate joints.
• Traditional crimping methods are operator-dependent and can compromise cable insulation and joint integrity.
• Existing aluminothermic welding presents challenges with high temperatures and reaction control.

Purpose of the Study:

• To develop an improved method for 10 kV cable intermediate joint connections.
• To optimize Sn-1.5Cu-based solder by investigating the optimal indium (In) content.
• To evaluate the performance of the new joint connection method.

Main Methods:

• Exploration of optimal indium content in Sn-1.5Cu-based solder using microalloying principles.
• Fabrication of 10 kV cable intermediate joints using a connecting die and electrical connection process.
• Testing of joint contact resistance and tensile strength.

Main Results:

• Solder with 3.8% and 5% In content achieved maximum conductivity of 3.236 × 10^6 S/m.
• The highest solder wettability reached 93.6%.
• The optimized intermediate joint exhibited a minimum contact resistance of 7.05 μΩ, 43% lower than aluminothermic welded joints, with comparable tensile strength.

Conclusions:

• The developed brazing method using optimized Sn-1.5Cu-In solder is a feasible and effective alternative for 10 kV cable intermediate joints.
• This technique significantly reduces contact resistance while maintaining high tensile strength, addressing limitations of traditional methods.
• The findings contribute to more reliable and durable underground power cable infrastructure.