How to suppress interference from long cables in power line carrier PLCs?

Suppressing interference from long power line carrier PLC cables requires shielding, filtering, and termination matching. Use shielded cables with both ends of the shield grounded (length < λ/20). Deploy common-mode inductors (CML4532A-510T) at both ends of the cable to suppress common-mode noise. For differential-mode interference, add ferrite cores (e.g., nickel-zinc ferrite) to the cable to increase high-frequency losses. Use termination matching resistors (e.g., 120Ω) to eliminate reflections. Analyze long-line transmission characteristics through simulation to optimize the matching network. In actual tests, interference suppression can improve the signal-to-noise ratio by 20dB on a 100-meter cable. Suppressing long-line interference can extend communication distance and is suitable for distributed systems.