Discussion on Safety Problem of Grounding Mesh in 500 kV Wennan Substation

From the point of view of grounding impedance, grounding potential, contact voltage and step voltage, the safety problems of grounding mesh in 500 kV Wennan Substation were discussed and analyzed, which located at high soil resistivity area. The corresponding measures for safety were put forward, such as adding insulation section on metal water pipe for outgoing of outside substation, adopting optical cable for telecommunication cables, checking and calculating the contact voltage and step voltage, reducing the induction voltage of cable, as well as adopting concentrated grounding installation for lightning rod. The grounding resistance of grounding mesh can be up to 0.5 Ω , which can still ensure operation and personal safety in substation.