Study and Improvement of Substation Earthing

Designing a proper substation grounding system is quite complicated. Many parameters affect its design. In order for a grounding design to be safe, it needs to provide a way to carry the electric currents into the ground under both normal and faulted conditions. Also, it must provide assurance that a person in the vicinity would not be endangered. The grounding portion of substation design will be explored. In order to properly plan and design the grounding grid, calculations of the following will be done: maximum fault current, grid resistance, grid current, safe touch and step voltages, ground potential rise, as well as expected touch and step voltage levels. Background information and guidelines to design a substation grounding grid will be provided. A set of equations will be presented to calculate whether the design is safe, and finally, an example will be provided that can be used as a template.