How to ensure EMC for long-distance data transmission of intelligent low-voltage monitoring units?

For long-distance data transmission, EMC assurance is provided using fiber optic transmission or reinforced cable protection.

Fiber optic transmission: Industrial-grade fiber optic transceivers are used, with a transmission distance of 2km. If cables are used, shielded twisted-pair cable with repeaters is employed, and signal conditioning is added every 500 meters.

Interface protection: CMZ3225A-510T common-mode inductors and ESDSM712 protection are installed at both ends of the cable.

With this assurance, the remote transmission system can pass the IEC 61000-4-5 4kV surge test with a bit error rate of less than 10^-9.