The contact resistance between grounding materials and soil is an important part of grounding resistance of grounding grids. However

at present

the design of grounding grids usually assumes that the grounding materials and soil are in ideal contact

which may bring a large error to the design value of grounding resistance. In this paper

a method for measuring and assessing the contact resistance between grounding materials and soil was proposed. A test platform for the contact resistance between grounding materials and soil was established. Then

combined with the finite element simulation

the contact characteristics of graphite based flexible grounding material and round steel with several soil types were compared. Finally

it was proposed to simulate the contact resistance through an equivalent coating in the simulation design of grounding grids. The research results show that the method of this paper can be adopted to effectively assess the contact resistance between the grounding materials and the soil

and the contact characteristics between graphite based flexible grounding material and typical mountainous soil is significantly better than that of round steel. The contact resistance between graphite based flexible grounding material and soil accounts for 1.83%～1.95% of the power frequency grounding resistance

while the contact resistance between round steel and soil accounts for 6.79%～7.57%.