Safety performance evaluation of fence grounding configurations in high voltage installations

The design of the grounding configuration for the metal fence of a high voltage installation is important as the outside perimeter of the fence is accessible to the general public. In this work the safety provided by several fence grounding techniques commonly used in high voltage installations is evaluated for a 150/20 kV air insulated substation, a 400 kV step-up GIS substation and a large scale photovoltaic power station with the aid of grounding analysis software. A safe and cost-efficient fence grounding design depends on ground fault characteristics, soil conditions, installation area, distance between the fence and grounding grid as well as on the size and geometry of the latter.