Using bentonite to reduce resistance Sometimes it is not possible to achieve the desired reduction in ground resistance by adding more grid conductors or ground rods. An alternate solution is to effectively increase the diameter of the electrode by modifying the soil surrounding.
The Annex H in IEEE Standard 80-2013 contains benchmark case results for comparing and evaluating software tools and methodologies used for the analysis of substation earthing.
The results compare the simple equations from IEEE Std 80 with the results given by some of the commercially available software such as CDEGS, ETAP, SGW, SDWorkstation and WinIGS.
A safe earthing system design has two objectives; to provide a means to carry normal and fault current without exceeding equipment limits or adversely affect continuity of service and to reduce the risk of a person in the vicinity of an earthed facility being exposed to the danger of a critical electric shock.
Switchgear in substations is installed on top of concrete slabs containing substantial quantities of steel reinforcement. Often the embedded steel reinforcement is bonded to the main earthing system and used to cost-effectively improve earthing electrical performance and safety.
The purpose of transmission line grounding is to provide adequate lightning performance of the line; and effectively dissipate fault current avoiding the build-up of unsafe step and touch potentials around the tower base.
To model the influence of an additional substance surrounding the conductors of a buried earthing system on grid resistance, touch and step voltages.