analyse Wener 's method for mesuring soil resistivity

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sadeghi

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Dear Sir;

we used Wener method to mesuring soil resistivity of HV substation site in three different directions.now we have three colection of numbers that one of them have results with magnitude more than towise of assosiated numbers in 2 others.
How we must calculate resistivity for whole of site?

Yours
Sadeghi
 
What is the measurement at 62% between the electrode under test (X)and the furthest test probe (Y).

What is the size of the grid under test?

How far did you go out.

How many test did you make per measurement, 1 foot and 10% increments there after with a measurement at 62%?

Depending on the location it is not unusual for soil to be varying, in different directions based on back fill, moisture, soil content (rock, clay, sand), location of existing power lines, fences, rail lines, underground pipes.
 
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What is the measurement at 62% between the electrode under test (X)and the furthest test probe (Y).
Click to expand...
This measurement concerns a 3-point resistance measurement. The OP concerns a 4-point resistivity measurement.

The first thing to do is to review the physical location of the measurements to determine if there is anything that would have unduly influenced the current returns on any of the measurements. Things like parallel grounding paths such as buried pipes or grounded transmission structures. Is there any reason to believe that there is a soil structure that would give a higher reading in one location?

Then draw a curve of resistivity vs depth. Are they fairly smooth curves in all three locations? Maybe there is a measurement out of line with the others that might indicate a problem with potential or current probe soil contact.

The conservative approach would be to use both the high resistivity measurements and the low resistivity measurements separately in the design. Calculate step- and touch-voltages separately. Because the current split will be different depending on the resistivity, you cannot assume that the high resistivity measurements will give the most conservative result.
 
Wener 's method for mesuring soil resistivity

Wener 's method for mesuring soil resistivity

brian john said:
What is the measurement at 62% between the electrode under test (X)and the furthest test probe (Y).

What is the size of the grid under test?

How far did you go out.

How many test did you make per measurement, 1 foot and 10% increments there after with a measurement at 62%?

Depending on the location it is not unusual for soil to be varying, in different directions based on back fill, moisture, soil content (rock, clay, sand), location of existing power lines, fences, rail lines, underground pipes.
Click to expand...

Dear Sir;

Please note that:

1.project is in design stage.
2.dimension the land of site is, 100m*100m.
3.there is no metalic object inside & under the ground.
4.measurings were down in three axes, Line bay, Transformer bay & Control bulding.
5.mesurings were down in Aug. at very dry erea.
6. results are as follow:

space of ele. (m) ; ohm.m of : L.B Tr.B C.B
2.5 16.0 120.0 15.2

5.0 20.1 102.1 22.9

10.0 39.7 90.4 35.8

20.0 51.5 59.3 23.9

As it seems transformer bay has defferent resistivity compare to line bay & control bay!
Please let me know your idea to determine a resistivity for whole erea.
Yours
Sadeghi
 
Wenner 's method to measuring resistivity of soil

Wenner 's method to measuring resistivity of soil

brian john said:
What is the measurement at 62% between the electrode under test (X)and the furthest test probe (Y).

What is the size of the grid under test?

How far did you go out.

How many test did you make per measurement, 1 foot and 10% increments there after with a measurement at 62%?

Depending on the location it is not unusual for soil to be varying, in different directions based on back fill, moisture, soil content (rock, clay, sand), location of existing power lines, fences, rail lines, underground pipes.
Click to expand...


Dear Sir;

Please note that:

1.project is in design stage.
2.dimension the land of site is, 100m*100m.
3.there is no metalic object inside & under the ground.
4.measurings were down in three axes, Line bay, Transformer bay & Control bulding.
5.mesurings were down in Aug. at very dry erea.
6. results are as follow:

space of ele. (m) ; ohm.m of : L.B Tr.B C.B
2.5 16.0 120.0 15.2

5.0 20.1 102.1 22.9

10.0 39.7 90.4 35.8

20.0 51.5 59.3 23.9

As it seems transformer bay has defferent resistivity compare to line bay & control bay!
Please let me know your idea to determine a resistivity for whole erea.
Yours
Sadeghi
 
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