underground fault locator

[jaimin parmar]

Hi
i am making under ground fault locator project and i am confused how can i sense dc current in cable and how i display the distance on lcd using microcobtroller
so plz help i am new in electronic world
thanx

 

[(*steve*)]

Hi Jaimin, welcome to Electronics point.

In general, you sense DC current by means of the magnetic field it generates. However the strength of the magnetic field depends on several things, current and distance being the most obvious.

To put it simply, if one is unknown, it is pretty much impossible to figure out the other one.

What related experience do you have? This sounds like a very ambitious first project to me.

 

[KMoffett]

In determining how to determine were a fault is, you need to define what constitutes a fault:
1. Normal/degraded signal/current/voltage on the conductors
2. Fault Open (full or partial)
3. Fault Short (full or partial) to external conductors
4. Fault Short (full or partial) between internal conductors

If the conductors are not shielded in steel conduit there are RF radiating signal tracers that may work. But this means walking the path of the cable, not a digital display. Otherwise research time-domain reflectometers.

Ken

 

[Arouse1973]

If you want to induce a current into your measuring device you can only do this if the magnetic field is changing. Otherwise you have to measure the electric field. If you are able to connect to one side of the wires you could make a TDR which sends out a pulse and measures the time for the signal to come back. You convert this to distance and your done. This will pick up open circuits and shorts.
Just a thought
Adam

 

[shrtrnd]

I'm with Arouse1973. Look up information on TDR's (Time Domain Reflectometers).
Most industrial electronics now is switching to fiberoptics, but in the (not too long ago)
'good old days' we used TDR's to determine the length of cable (wire) runs across the
plantsite using a TDR. Cable salesmen that came to the plant used their own TDR
to determine exactly how many feet of cable (wire) were left on their reels for sale.
You can find them on ebay, if you're serious about using one, finding out how they work.