TFR Query

[SauravWest]

Dear Sirs,

Could somebody please share how can we measure tower footing resistance of overhead lattice type transmission towers of 132 kV or 220 kV length

Counterpoises are what we are using.

Regards,

 

[SauravWest]

Is three pole method suitable?

 

[sushilksk]

for three pole method, isolation of counterpoise earthing under test from lattice structure is required. Measurement with clamp type earth tester is easy solution, which does not require isolation. Example:

http://www.motwane.com/dect-3.html

 

[SauravWest]

the reading is to be taken across the line (ie perpendicular to the line direction)?

 

[jghrist]

If the counterpoise is connected at more than one point on the tower, you would have to disconnect all but one point to use a clamp-on type ground tester. The foundations will be part of the grounding electrode, particularly if the anchor rods are bonded to the rebar. It's hard to get a clamp-on ground tester around the tower.

You could insulate the shield wires from the tower temporarily and use the three-point method. Make sure that you don't get close to another tower ground with the current probe.