Grounding grid next to a river

[radug]

Hello,

I am calculating a grounding grid based on IEEE 80-2000 for a Power Plant next to a river. I read the standard but did not find any specific words about grid design near rivers.
Is there any special concerns that I should consider?

Thanks.

 

[JensenDrive]

I wish I had something to add. This is interesting. Water by itself is a poor conductor, and I do not now if the river improves grounding or not.

 

[dpc]

If anything, the river should help the nearby soil stay moist which will lower the soil resistivity. Should not be any special issues unless there is a concern that everything will be washed away. Moisture in the soil is nearly always a good thing when it comes to grounding.

 

[Zogzog]

I would guess there would be a big difference if this is a pure mountian spring fed river or the Detroit river

 

[TurbineGen]

I am doing a similar project. As dpc said, if the river increases the moisture content of the soil, it will lower the ground resistivity. You might want to consider materials that are very resistant to corrosion for this. You might want to take several soil samples at varying distances from the river to get an accurate measurement for the soil conductivity.

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If it is broken, fix it. If it isn't broken, I'll soon fix that.

 

[jghrist]

With some grounding software (such as CDEGS), you can model a river so that it is taken into consideration in the grounding analysis.

 

[radug]

Thanks for all the replies.

Soil measurements near the river are all around 14ohms.meter.

My concern is about the loading docks with gas pipes, because simulations give me dangerous touch voltages, so, should a grounding grid be buried below water surrounding the docks? That would be very expensive.


jghrist,

I am using CDEGS to model the ground grid, but I did not know it allowed to model a river. I have been searching the help but was not able to find anything. Could you please tell me how to model the river?

 

[controlsdude]

water distilled that is strained by carbon filter, oxygen taken out, and a micron filter is actually an insulator.

I remember from my radar days in navy and I know if their a certain amount of the above particulate (oxygen level or small particles of matter) in the water that it turns into a conductor.

Any river water would conduct electricity like any conductor.

 

[jghrist]

radug,

You can use a horizontal cylindrical soil model. See CDEGS Help under MALT/Define Soil Types/Cylindrical Soil Layers.

There was a paper in the 2001 Users Group Meeting on the subject. The Effects of Low Resistivity Cylindrically
Shaped Soil Volumes on Grounding Systems by Y. Yang, J. Ma and F. P. Dawalibi

 

[groundperfect]

Check out this link on deep earth vs shallow earth grounding.

http://www.groundperfect.com/deepearthpaper.htm

We have driven many rods near river banks and even though you would think the top soil would be good in that location and stay consistant year round it is not always the case. I should look back and get test results from the first 10' of ground rods we have installed over the last 20 years near sources of water. Very few would be near 1 Ohm for sure as I've found very few systems that can produce that low of resistacne using commong grounding practice and remain consistant year round. Not to mention most are impossible to test without totally disconnecting the system from the outside world and that leaves life safety to chance. Driving deeper rods possibly 100 feet plus and spaced apart as far as they are long gives a more consistant ground as the earth is much more stable at those depths. We also use stainless steel as it lasts much longer than copper in the ground.