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Posted: 11/3/2009 2:36:01 PM EST
[Last Edit: 11/3/2009 3:08:49 PM EST by AgentDavis]
I'm in a class about Networking and we're discussing what things can effect transmission. The book mentions several types of Interference, one of them being Electromagnetic Interference(EMI). A footnote on the same page mentions cars being disabled when they drove over high-voltage power lines underneath the highway. Is that possible or is the author blowing smoke up our asses?
Link Posted: 11/3/2009 3:23:00 PM EST
Anybody?
Link Posted: 11/3/2009 3:23:41 PM EST
HERF
Link Posted: 11/3/2009 3:28:01 PM EST
I wouldn't fly the BS flag immediately because anything's possible, but I find it highly unlikely that driving over HV cables would disrupt the ECU of a normal car.
Link Posted: 11/3/2009 3:32:30 PM EST
[Last Edit: 11/3/2009 3:35:36 PM EST by AR-Josh]
Short answer yes. I am so far away from that stuff. I have not looked at it since I left the class.

Current through a wire produces a magnetic field. A magnetic field going perpendicular to a wire induces a current in that wire. If you want details, look up magnetic fields and the right hand rule.
Link Posted: 11/3/2009 3:32:48 PM EST
I'm an electrical engineer in power transmission. I do 138kv and 345kv design.

We don't have any issues with cars. The large issues are really with rail traffic. If the rail runs parallel to a 345kv tower line for long distances, bad shit can happen. There are all kinds of tricks for avoiding those issues, so even that's not a huge problem.

The lines are specifically designed with EMF issues in mind. We run communication lines, both optical and traditional, very near the phases with the high voltage stuff. Data transfer, as long as it isn't by pigeon, is generally not affected by our lines.
Link Posted: 11/3/2009 3:42:11 PM EST
Originally Posted By 3-Phase:
I'm an electrical engineer in power transmission. I do 138kv and 345kv design.

We don't have any issues with cars. The large issues are really with rail traffic. If the rail runs parallel to a 345kv tower line for long distances, bad shit can happen. There are all kinds of tricks for avoiding those issues, so even that's not a huge problem.

The lines are specifically designed with EMF issues in mind. We run communication lines, both optical and traditional, very near the phases with the high voltage stuff. Data transfer, as long as it isn't by pigeon, is generally not affected by our lines.


I'd like to hear more about the 345 - rail coupling

On the automotive side, there are pretty rigorous standards for EMI immunity in automobiles, particularly with more control systems (ABS etc) which are critical to safety.

Unless the lines were much closer than normal to the road in your example (near field) I think it is unlikely, or in a country with much lower EMC standards (not the US or Europe)

Link Posted: 11/3/2009 3:42:48 PM EST
Originally Posted By 3-Phase:
I'm an electrical engineer in power transmission. I do 138kv and 345kv design.

We don't have any issues with cars. The large issues are really with rail traffic. If the rail runs parallel to a 345kv tower line for long distances, bad shit can happen. There are all kinds of tricks for avoiding those issues, so even that's not a huge problem.

The lines are specifically designed with EMF issues in mind. We run communication lines, both optical and traditional, very near the phases with the high voltage stuff. Data transfer, as long as it isn't by pigeon, is generally not affected by our lines.


do you transpose the lines at intervals?

Link Posted: 11/3/2009 3:45:54 PM EST
[Last Edit: 11/3/2009 3:47:51 PM EST by JonnyVain]
Originally Posted By 3-Phase:
I'm an electrical engineer in power transmission. I do 138kv and 345kv design.

We don't have any issues with cars. The large issues are really with rail traffic. If the rail runs parallel to a 345kv tower line for long distances, bad shit can happen. There are all kinds of tricks for avoiding those issues, so even that's not a huge problem.

The lines are specifically designed with EMF issues in mind. We run communication lines, both optical and traditional, very near the phases with the high voltage stuff. Data transfer, as long as it isn't by pigeon, is generally not affected by our lines.


Optical data isn't effected at all by power transmission. Things like ethernet through CAT5 uses a current, so that would be.

Originally Posted By Merrell:
Originally Posted By 3-Phase:
I'm an electrical engineer in power transmission. I do 138kv and 345kv design.

We don't have any issues with cars. The large issues are really with rail traffic. If the rail runs parallel to a 345kv tower line for long distances, bad shit can happen. There are all kinds of tricks for avoiding those issues, so even that's not a huge problem.

The lines are specifically designed with EMF issues in mind. We run communication lines, both optical and traditional, very near the phases with the high voltage stuff. Data transfer, as long as it isn't by pigeon, is generally not affected by our lines.


I'd like to hear more about the 345 - rail coupling

On the automotive side, there are pretty rigorous standards for EMI immunity in automobiles, particularly with more control systems (ABS etc) which are critical to safety.

Unless the lines were much closer than normal to the road in your example (near field) I think it is unlikely, or in a country with much lower EMC standards (not the US or Europe)



Since he said over time, I would be let to believe that the EMI causes a capacitance build up somewhere in the trains.
Link Posted: 11/3/2009 4:23:01 PM EST
Originally Posted By AgentDavis:
A footnote on the same page mentions cars being disabled when they drove over high-voltage power lines underneath the highway. Is that possible or is the author blowing smoke up our asses?


That sounds REALLY unlikely. Automotive electrical systems are built to tolerate a lot of EMI anyway, simply due to the fact that plenty of devices in the car produce lots of EMI - Things like ignition coils, motor brushes, relay coils, etc. Also, most of a vehicle's wiring is effectively shielded by the metal body components, and is relatively short in length (long conductors tend to pick up more EMI than short ones).
Link Posted: 11/3/2009 4:35:00 PM EST
[Last Edit: 11/3/2009 4:38:37 PM EST by Quintin]
Link Posted: 11/3/2009 5:10:40 PM EST
Thanks for all the input, It makes me happy to know that so many people with knowledge in such a wide range of topics can all come together here.

So, The general consensus would be that it is very unlikely, but still possible?
Link Posted: 11/4/2009 3:11:18 AM EST

Originally Posted By AgentDavis:
Thanks for all the input, It makes me happy to know that so many people with knowledge in such a wide range of topics can all come together here.

So, The general consensus would be that it is very unlikely, but still possible?

On paper it is possible. Real life...maybe Mythbusters will do an episode.
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