Improvement of Shaped Conductive Backfill Material for Grounding Systems

In this paper, some improvements have been proposed for low resistance shaped conductive backfill material (SCBM) based on finite-difference timedomain (FDTD) simulations in grounding systems. It is found SCBM can be produced by conjunction of several layers with conductivity decreasing gradually from inner layer to outer layer, and smooth conductivity reduction between layers would lead to a better grounding performance. It is also found cuboid shape is a much more efficient shape than cube and cylinder shapes for SCBM, and holes can be made on the SCBM’s main body. It suggested to bury SCBM vertically when ground soil permits, otherwise bury SCBM horizontally and deeper burying depth would result in smaller grounding resistance. Results show it is not needed to connect the SCBMs one by one tightly in series SCBM, and some distances is allowed without dramatically increasing grounding resistance.