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Magnetic field of a soil buried DC current carrying conductor

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Hi everyone I am working on a 3D model for calculating the stationary magnetic field of a buried current carrying conductor on surface of air. I am calculating the current using Ampere's law for 1 meter depth of conductor. The main issue I am facing, the magnitude of magnetic field density (B) is quite less nearly half. When I decrease the value of depth or increase relative permeability (mur) of soil I get the better values of B of x,y,z components. I kept the following relative permeability values for materials:

Soil = 1 S/m Air = 1.006 Copper conductor = 1.00000037

Is there any issue in comsol model? Can I increase the value of 'mur' of soil for this depth? Please let me know if any body have the solution. Thanks


6 Replies Last Post 2023/04/19 5:25 GMT-4
Edgar J. Kaiser Certified Consultant

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Posted: 1 year ago 2023/04/12 4:17 GMT-4

Hm, S/m is the unit for electrical conductivity, not permeability.

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Edgar J. Kaiser
emPhys Physical Technology
www.emphys.com
Hm, S/m is the unit for electrical conductivity, not permeability.

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Posted: 1 year ago 2023/04/13 2:12 GMT-4

Dear Edgar J. Kaiser

Thanks for your correction. It was written by mistake. The permeability values are:

Soil = 1 Air = 1.006 Copper conductor = 1.00000037

Dear Edgar J. Kaiser Thanks for your correction. It was written by mistake. The permeability values are: Soil = 1 Air = 1.006 Copper conductor = 1.00000037

Edgar J. Kaiser Certified Consultant

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Posted: 1 year ago 2023/04/13 3:14 GMT-4
Updated: 1 year ago 2023/04/13 3:15 GMT-4

Ok, but with the information you provide nobody can even guess what the problem may be.

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Edgar J. Kaiser
emPhys Physical Technology
www.emphys.com
Ok, but with the information you provide nobody can even guess what the problem may be.

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Posted: 1 year ago 2023/04/18 7:02 GMT-4

Dear Edgar J. Kaiser

Sorry for late reply, I elaborate it more and attached some snaps of model and magentic field of 'By' component. In model, one block is used for soil while other one is air. The copper conductor length is 5m and radius is 0.019m. I applied 5 volt dc and comsole calculated 60 kA app. using current density Jx. I used two tools, they are mef and coefficient of PDC. Please someone suggest, how can I get the value of By = 0.011 T or above from this model?

Dear Edgar J. Kaiser Sorry for late reply, I elaborate it more and attached some snaps of model and magentic field of 'By' component. In model, one block is used for soil while other one is air. The copper conductor length is 5m and radius is 0.019m. I applied 5 volt dc and comsole calculated 60 kA app. using current density Jx. I used two tools, they are mef and coefficient of PDC. Please someone suggest, how can I get the value of By = 0.011 T or above from this model?


Robert Koslover Certified Consultant

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Posted: 1 year ago 2023/04/18 15:10 GMT-4

I didn't plug in your numbers, but your electric wire looks too close to the lower computational boundary, which could impact your computation. I suggest you extend your computational space further downward (to provide more distance from the wire to the lower boundary) and then rerun the model. (Also, you might want to post your .mph file, not just .jpgs.)

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Scientific Applications & Research Associates (SARA) Inc.
www.comsol.com/partners-consultants/certified-consultants/sara
I didn't plug in your numbers, but your electric wire looks too close to the lower computational boundary, which could impact your computation. I suggest you extend your computational space further downward (to provide more distance from the wire to the lower boundary) and then rerun the model. (Also, you might want to post your .mph file, not just .jpgs.)

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Posted: 1 year ago 2023/04/19 5:25 GMT-4

Dear Robert Koslover

Thank you for your response. When I read your message, I guessed that my issue has resolved. Thats true, I applied your suggested modification on model and got the required value of By component. Once again thank you Robert Koslover and Edgar J. Kaiser for your gauidance and help.

Dear Robert Koslover Thank you for your response. When I read your message, I guessed that my issue has resolved. Thats true, I applied your suggested modification on model and got the required value of By component. Once again thank you Robert Koslover and Edgar J. Kaiser for your gauidance and help.

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