Subject:  Re 50 amps in oil pipeline (fwd)
Date:     Mon, 27 Jul 1998 030511 -0500 (CDT)
From:     "Roy L. Beavers" <rbeavers@llion.org>
To:       emfguru@hotmail.com
--------------------------------------------------




---------- Forwarded message ----------
Date: Sun, 26 Jul 1998 22:20:42
From: Alasdair Philips 
To: "Roy L. Beavers" 
Cc: Edward Maxey 
Subject: Re: 50 amps in oil pipeline (fwd)

Roy
>From Ed's query. I wasn't going to respond but he chased me in a reply to a
personal email about something else!.....

>These observations using Biott and Savart's law indicate 
>a 60 Hz AC current slightly in excess of 50 amperes
>in the pipeline.
I agree. I make it about 48 amps ac. This is a lot of current and something
may well be getting warm somewhere along the line if it is mainly coming
from a single source.
Utilities have multiple earth/neutral connections which can give rise to
large net error currents chosing to flow long distances in highly
conductive pipework which will offer a lower impedance than the utilities
cables!
>
>Perhaps some of your listees have expertise in oil pipe
>lines and might offer suggestions as to:

>1. the source/sources of the AC current,
The pipeline is obviously a better conductor than the
utility earths....or.....
it is providing a nett error return current flowing between two different
systems (less likely)
See BEMS 18:307-316 (1997) for currents on water pipes.

>2. methods of remedy and

(i) I'm not sure that it is legal for oil pipes to carry
more than a tiny current. I am sure it isn't in the UK under safety
regulations for oil/gas & electricity. They are very strict as
theoretically you can get sparks as other metal objects touch the pipe.
This would be the easiest way of swinging the duty to remove the current
onto the pipeline operators.

(ii) Inserting a non-conductive section into the pipeline at intervals is
the ONLY way be be sure of stopping stray currents from flowing.

(iii) Try to trace where the current is entering and leaving the line.
This is usually difficult to do as it often arrives and departs at multiple
locations.
If you find the locations as actual metallic connections then it might be
possible to add some inductance to decrease the ac current (see my note
under 3, below)

>3. whether or not a DC potential maintained on the 
>   pipeline to prevent corrosion is contributing to
>   the AC current problem.

Most unlikely although it might be providing the source or drain connection
for the 50 amps ac.  If it is then the chokes of Heath Hofman which Ed told
us about last year would stop the ac flowing but allow dc through. Remember
- the chokes are basically a few turns of wire on a power transformer core
to give some inductance.







At 19:02 23/07/98 -0500, Roy L. Beavers wrote:
>
>
>---------- Forwarded message ----------
>Date: Thu, 23 Jul 1998 14:52:42 -0500
>From: Edward Maxey 
>To: "Roy L. Beavers" 
>Subject: 50 amps in oil pipeline
>
>Hi Roy,
>
>A gentleman, D.F., recently contacted me about electrical
>problems which he attributed to an underground oil pipe
>line that crossed his rural property.  He had borrowed
>a milligauss meter which had a maximum reading of 10 mG.
>This meter pegged at maximum when he was about ten
>yards from where he thought the pipe line was buried.
>
>He was asked to approach the pipe line at right angles and
>note the spots where the meter read 5 mG and 10 mG.  He was 
>then to measure the distance between these two spots.
>
>D. F. later telephoned to indicate that he had measured the 
>distance between these two marked spots at 34 feet.
>
>These observations using Biott and Savart's law indicate 
>a 60 Hz AC current slightly in excess of 50 amperes
>in the pipeline.
>
>Perhaps some of your listees have expertise in oil pipe
>lines and might offer suggestions as to:
>1. the source/sources of the AC current,
>2. methods of remedy and
>3. whether or not a DC potential maintained on the 
>   pipeline to prevent corrosion is contributing to
>   the AC current problem.
>
>Good wishes,
>Ed
>
>
 
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Alasdair Philips    (aphilips@gn.apc.org)
Director, UK Powerwatch,
EMC Engineer and EMF-bioeffects researcher
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~




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Reprinted with permission of Roy Beavers, http://www.feb.se/EMF-L/EMF-L.html