How to ensure EMC for long-distance power FTU transmission?

For long-distance transmission (>1km), EMC assurance must consider line attenuation and interference accumulation. Fiber optic transmission should be used instead of cables to completely isolate electromagnetic interference. Industrial-grade fiber optic transceivers, such as the HFBR-1414, should be selected for a transmission distance of 2km. A DC-DC isolation module WRB2405S-3W should be used for the power supply. If cables must be used, shielded twisted-pair cables with repeaters should be used, with signal conditioning added every 500 meters. Interface protection: CMZ3225A-510T common-mode inductors and ESDSM712 protection should be installed at both ends of the cable. With this assurance, the long-distance transmission system can pass the IEC 61000-4-5 4kV surge test with a bit error rate of less than 10^-9.