Safe Distances between High-Speed Railway 10 kV/0.4 kV Indoor Substations and Signal Rooms

［Objective］ When railway 10 kV/0.4 kV indoor substations and signal rooms are constructed at the same location, electrical equipment and signal equipment arranged too far apart will waste land resources, while placing them too close may cause electromagnetic compatibility issues. Thus, it is necessary to study the safe distance between the two. ［Method］ Through electromagnetic environment simulations and field tests, the distribution of power frequency electromagnetic fields in 10 kV substations is understood. Simulations are conducted following the GB/T 17626.8—2006 Electromagnetic compatibility-Testing and measurement techniques-Power frequency magnetic field immunity test and GB/T 24338.5—2018 Railway applications-Electromagnetic compatibility-Part 4: Emission and immunity of the signaling and telecommunications apparatus standards, calculating magnetic field intensity for both exposed transformer busbars and those enclosed in steel plate housings. The results are compared with the magnetic field limit values specified for sensitive equipment in above standards. In field tests, the electromagnetic field intensity generated during normal operation and short-term faults of electrical equipment in the substation is measured. ［Result & Conclusion］ The indoor magnetic field intensity is related to the relative distance from the electrical equipment. At 1 m from the electrical equipment, the electric field intensity is significantly below 4 kV/m, and the magnetic field intensity is below 30 A/m. The minimum safe distances between electrical and signaling equipment are determined to be 0.96 m for exposed equipment and 0.28 m for enclosed equipment in steel plate housings.