Electrical Isolation of Two Earthing Systems under Lightning Conditions with TiO2 Nano Fluid Barrier

A Titanium dioxide (TiO
₂
) nano fluid based potential barrier is proposed to separate two earthing systems which are in the proximity with each other, yet, should not have a transfer of potential between them. Such systems are often required in MV/LV transformers that have delta-star configuration. The TiO
₂
in the nano-fluidic form extruded into the cavity in the ground, get mixed with surrounding soil to form an extremely high resistive medium that prevents the electrical continuity between the two electrode systems via soil. Laboratory experiments show that depending on the resistivity and nature of the surrounding soil the resistivity of the TiO
₂
-soil mixture could have resistivity that vary from about 10
⁵
Ωm to 10
¹²
Ωm. By extruding to ground a 5 cm thick, semi cylindrical TiO
₂
nano-fluid mix of resistivity 10
⁷
Ωm, having a radius of 2 m and depth of 1 m below the electrode length, the potential at a boundary point of the barrier could be reduced from 75 kV to 1.85 kV when 100 kV impulse is injected to the earthing electrode.