Abstract: The helium cryogenic system, a core infrastructure for superconducting magnets and particle accelerators, requires highly secure, stable, and efficient power supply and distribution. This study explores key technologies such as HV/LV power distribution design, selective protection settings, and process grounding optimization, using a hard X-ray cryogenic plant as an example. A hierarchical framework (10kV substation, 10/0.4kV transformer station, terminal equipment) combined with short-circuit analysis and lightning protection ensures system redundancy. Results indicate that optimized protection parameters (e.g., 1.15×rated current for long-time delay, instantaneous thresholds surpassing soft-start peaks) ensure stable compressor operation, while grounding resistance (≤1Ω) and lightning protection meet safety requirements.