How do the power FTU and the distribution master station's EMC work together?

The FTU and master station communication EMC coordination requires unified grounding and interface standards.

Grounding coordination: Equipotential bonding is used, with both grounds connected through a low-impedance grounding network, and the grounding resistance less than 0.1Ω.

Interface standards: IEC 60870-5-104 or IEC 61850 protocols are uniformly adopted, with electrical interfaces using RS485 or Ethernet, and consistent protection levels.

Signal level matching: Standard levels are used (e.g., ±2V~±6V for RS485).

Cable specifications: Shielded twisted-pair cables of the same specification are used.

Through coordinated design, the overall communication system passes the IEC 61000-4-5 4kV surge test, with a bit error rate of less than 10^-6.