Grounding Test Using Slope Method
Grounding Test Using Slope Method
(OP)
We are testing a large ground grid, approximately 400 feet by 200 feet using the fall of potential slope method with the C2 electrode distance of 500 feet from the test point of the grid. Attached is the test report for the grounding system with noted results. We have been told this is not a valid test and need a second opinion.
Thanks
Thanks






RE: Grounding Test Using Slope Method
www.bi
RE: Grounding Test Using Slope Method
I would try including the slope calculations and a reference to an explanation of the slope method.
RE: Grounding Test Using Slope Method
I don't know why you could not open the attachment, I tried and it opened right up.
RE: Grounding Test Using Slope Method
Your test is accepted to me. But two notes.
1)In slope method, normally distance C2 to be taken as 2-3 times the largest dimension of the grid. The diagonal distance is 447 feet. That means if you have taken 2.5 times say 1118 ft (I donot know whether it is possible at the site)then the result would have been more accurate.
2)In slope method, normally the test should be repeated for a larger distance of C2.Therefore, is it possible to repeat the test for 1118 feet to check whether there is a considerable deviation from your first "True resistance value" of 1.072 Ohms?
Hope this helps
RE: Grounding Test Using Slope Method
Alan
----
"It's always fun to do the impossible." - Walt Disney
RE: Grounding Test Using Slope Method
The article, like some of us, old but still relevant.
RE: Grounding Test Using Slope Method
RE: Grounding Test Using Slope Method
I assume that the local testing company is using an EPRI Smart Ground MultiMeter developed by Sakis Meliopoulos and marketed by Advanced Grounding Concepts http://www.ap-concepts.com/win_sgm.htm. This method is not without controversy. See IEEE Transactions on Power Delivery, Vo. 8, No. 3, July 1993 pp 1095-1106, A PC Based Ground Impedance Measurement Instrument. A comment by F.P. Dawalibi (SES) was "Unfortunately, I have no alternative but to state that the authors have failed in their attempt" (to find an alternative to the fall-of-potential method).