We have been trying to located an intermittent short between a cathodically protected gas line and the copper grounding grid in a combustion turbine generating station.
The intermittent condition now has changed to a solid short dragging the pipe to soil potential down to -0.56V. We were operating at a -1.2 V on the best day as measured by a permanent reference cell hooked to our PI system. Manual pipe to soil potential readings verify the permanent cell output. The pipe is protected by a large anode bed with additional anodes installed at each point the pipe exits the ground.
The pipe has been dug up and exposed in a number of areas where pipe to soil potentials indicate the lowest potential ---with no shorts or grounds found.
In the general areas that point to the lower protection, we have installed double insulation (on both flanges on the valves where the piping comes from the ground).
Does anyone know of a technology that can locate a short within a few feet of the actual location?
My contact information is pcmyers@aep.com
Troubleshooting Cathodic Protection Systems
Re: Trouble shooting cathodic protection system
